Home

Working Model 3D

1. C5 Enter 500 as the value for angular velocity of this Revolute Motor as shown in Figure 3 23 You can close the Properties window now Properties of constraint 61 Concentric x Appearance Constraint Color Active Motor Motor Type C Orientation Angular Velocity C Angular Acceleration C Torque Value deg s Concentricl on Anchor 1 z axis 3 20 Exercise 3 Exploring CAD Integration and Associativity All CAD Packa gp i 1 Click the Run button in Working Model 3D s Tape Player Conirol The piston assembly rotates all the way around the crank pin as shown in Figure 3 24 Itno longer swings like a pendulum because the motor provides the driving force to keep the piston rotating Figure 3 24 Piston Head Rotating All the Way Around the Crank Pin 2 Click the Stop button 3 4 Adjusting the Joints When Working Model 3D exports the CAD model it creates joints between parts of the assembly The types of joints created depends on the constraints and geometry of the CAD model If the joints that Working Model 3D creates are not given the appropriate degrees of freedom the parts cannot move appropriately when you run the simulation To correct this problem you should verify and adjust the joints between the parts of the assembly as necessary to correctly specify the motion desired A Mechanical Desktop only 3 4 Adjusting the Joints 3 21 Currently th
2. 6 Click the global coordinate origin hold down the mouse button and drag the mouse downward to zoom in Note that if you move the mouse upward you can zoom out 7 Release the mouse button when the Edit Grid fills a reasonable portion of your document window You can repeat the previous step to zoom in further See Figure 4 3 for an example lt e Working Model 3D Untitled3 OLX Eile Edit View World Object Grid Measure Tools Window Help 18 x osje fel of eL ee fk o1slals e 2 2 3 ala 4 6 Sa Use the Zoom In Out tool If your Edit Grid does not appear to be quite centered use the Pan tool to shift the view laterally 4 2 Creating the Crankshaft In this exercise the crankshaft is simplified as a single disk and you will later attach a connecting rod from the piston to this disk so that the phase will be offset by 180 Figure 4 4 Properties Window Position Page for the Cylinder 4 2 Creating the Crankshaft 4 5 You will specify the geometry and position of the body using the Properties window 1 2 Click the Cylinder tool on the Sketch toolbar Click once on the Edit Grid then press the Enter key on your keyboard A small cylinder appears where you clicked Double click the cylinder in the document window or the Object Manager list The Properties window appears Click the Position Pos tab The Properties window displays the Position pag
3. m Rotate Around SS BF De C No axes C All Rigid Joint Spherical Joint Rigid Joint on Slot ne Revolute Joint on Slot Slide Along Spherical Joint on Slot cx ey ez 4 Linear Actuator amp Revolute Motor No axes B4 Repeat steps B1 thru B3 to change constraint 71 the other revolute joint on slot on the crank pin into a revolute joint 3 4 Adjusting the Joints 3 25 p C SolidWorks only Currently all of the parts in the piston assembly move together like a single rigid body In this step you will adjust the joints to give each the appropriate degrees of freedom Adjust the Joints on the Connecting Rod The connecting rod has been given too many constraints by Working Model 3D In this step you will remove one rigid joint that is currently preventing the true motion between the connecting rod and other assembly parts from occurring C1 Select CONNECTING ROD 1 in the Object List The Connections List displays the constraints and Coords attached to the connecting rod C2 Select Distance3 the rigid joint in the Connections List The Connections list displays the bodies and Coords attached to the rigid joint C3 Hold down the Control key and click on Distance3 on Crank 1 and Distance3 on CONNECTING ROD 1 the two Coords attached to the rigid joint in the Connections list The rigid joint Distance3 as well as the two Coords Dis
4. Genter of ma j m Meter C Graph e a 9 Choose Digital The force meter switches to the digital format You are now ready to run the simulation to take measurements To run the simulation 10 Click the Run button in the Tape Player Control The simulation begins to show the model in motion and the meters display the data as shown in Figure 4 35 Note that the angular velocity meter rescales the graph axes automatically as the data grows in magnitude Figure 4 35 Simulation with Meters 4 11 Improving the Model 4 33 e Working Model 3D Untitled3 _ Oy x File Edit View World Object Grid Measure Tools Window Help Cylinder Cylinder Revolute Rigid Joint i i Spherical it Spherical ES Angular Velocity Meter E constraint 15 for Meter b coord 3 Base Coola 3 We deg s vs t s gt i 8e 3 6e 3 4e 3 2e 3 0 0 TE For Help press F1 Frame 55 Time 1 1s 9 4 11 Run the simulation until several rotation cycles are completed and click the Reset button on the toolbar 12 Repeat the simulation Note that the simulation runs faster during the playback observe the jerky rotation of the crankshaft due to gravity 4 11 Improving the Model As the mechanism completes the cycle note that the force exerted by the spherical joint shows a huge spike especially when the crankshaft reaches the lowest point In addition the angular veloc
5. constraint 61 Revolute constraint 71 Revolute constraint 73 Revolute xj Connections 3 5 3 6 Exercise 3 Exploring CAD Integration and Associativity zy B Solid Edge onl is ge only B1 Launch the Solid Edge Assembly program Note that the WM3D toolbar appears at the left edge of the Solid Edge window as shown in Figure 3 6 Figure 3 6 WeHID x WM3D Toolbar in Solid Edge nE Helo Working Model for Solid Edge B2 Open the file Piston asm located in your Program Files Working Model 3D Tutorials Exercise 3 Solid Edge directory The CAD model of the piston assembly is displayed as shown in Figure 3 7 3 1 Exporting a CAD Model 3 7 Figure 37 Solid Edge Assembly Piston asm Solid Edge CAD Model ia File Edit View Insert Format Tools Window of Piston Assembly xs B3 Click the Gyroscope button in the WM3D toolbar The Working Model for Solid Edge dialog appears as shown in Figure 3 8 Figure 3 8 Working Mode for Solid Edge Dialog Model 3D T Show Coords Frocress Close About Help B4 Click the Build Model button Working Model for Solid Edge maps the assembly components and constraints into Working Model 3D bodies and joints and creates a new linked model named Piston wm3 in the same directory As Working Model 3D translates the geometry the progress is displayed in the Work
6. i i Note that the rotation axle was moved to the flywheel because you selected the rotation axis first For joint constraints the order of selection thus affects the assembly behavior By default Working Model 3D creates a revolute joint by allowing a single degree of freedom in rotation about the z axes of the two Coords Therefore when you created a revolute joint note that Working Model 3D aligned the following e the origins of the two Coords and e the z axes of the two Coords in the same direction As shown in Figure 5 16 the two Coords will not necessarily be aligned completely as the revolute joint allows free rotation about the z axes 5 16 Exercise 5 Modeling a Gyroscope Top Figure 5 16 Aligning Coords for a Revolute Joint ZpZ Z Z2 b lt 2 yI y2 y2 y a xX x2 X2 Two distinct Coords in space Fora revolute joint i ioj origin and z axes of the before creating a revolute joint Coords are aligned Other joints available in Working Model 3D follow principles similar to the revolute joint For example a spherical joint is constructed by aligning the origins of two Coords since the joint allows three rotational degrees of freedom the coordinate axes need not be aligned The next section illustrates how to construct a spherical joint 5 5 Attaching the Gyroscope to the Ground In this step you will fix the bottom end of the gyroscope axle to the ground through a spherical joint to allow t
7. the rotation axle will be moved to coord 6 the background so that the two Coords will be aligned see below for more information 6 Click the Create button located at the bottom of the window The gyroscope is moved and the spherical joint icon appears at the attachment point as shown in Figure 5 20 When creating a spherical joint Working Model 3D makes an effort to align the coordinate origins of the two Coords However since a spherical joint allows all three degrees of rotation the orientation of each Coord remains unchanged before and after the joint is created 5 22 Exercise 5 Modeling a Gyroscope Top Figure 5 21 Aligning Coords for a Spherical Joint In the same light note that the entire gyroscope assembly is translated so that the attachment points are aligned but it was not rotated It was only necessary to align the position of the Coords but not their orientations Figure 5 21 illustrates this principle Compare it with Figure 5 16 which describes the principles of the revolute joint Z z2 z2 Zy y2 y2 y1 Y X X2 2 X s Fora nical joint onl Two distinct Coords in space Adike ofthe ae before creating a spherical joint are aligned while their onentations are preserved 5 6 Giving Initial Spin to the Gyroscope To observe precession the gyroscope must have an initial angular velocity 1 Double click the flywheel body 1 in the drawing window or the Object List 1 Click
8. Torque Value if time lt 0 3 005 0 coord 3 z axis The expression is an example of Working Model 3D Formula Language and this expression is interpreted as follows If the elapsed time is less than 0 3 seconds apply the torque of 0 005 N m otherwise apply no torque Note that Working Model 3D interprets all the variables and numbers in formula expressions in SI units Even though the distance unit in the current unit system is set to millimeters you must enter the formula as if the distance unit is meters In this example you want the value of the torque to be 5 N mm so you must enter 0 005 N m the equivalent value in SI units For more information on the formula language please refer to the Working Model 3D User s Manual 4 14 Exercise 4 Creating a Piston Model Figure 4 16 Connecting Rod 4 4 Creating the Connecting Rod Next you will attach a connecting rod to the crankshaft Before doing so you may wish to zoom out so that the bulk of the Edit Grid is visible in your document window To sketch the connecting rod 1 2 Click the Box tool in the Sketch toolbar Click once on the Edit Grid then press the Enter key on the keyboard Open the Properties window by double clicking the box The Properties window appears Click the Position Pos tab Type the position as x y z 0 0 30 Click the Geometry tab Enter the dimensions as Width Length Height 5 70 5 Th
9. 17 1 10 Exporting a Video for Windows AVI File ee eeeeeeeeeeneeeeeeneeseeenee 1 18 1 11 Hints for Faster Animation eee ese eeeeeeeeeeeeeeeeeeeeeseneeeeseeeeeeeeeeeees 1 20 Analyzing a Piston MOCEI s ssssssssssssesesessssssusnsseeseeesesssussuunnnseeeeseessssnase 2 1 2 1 Opening a Model Fil ssvre penine ea E E N 2 2 2 2 Understanding Part Relationships essesesseseseesssresesresrserererrsrrerssrerrsreeesreese 2 3 2 3 Setting the Initial Condition eee ceseeeeceseeeeceeeeseceseeeeecaeeeaecaeesaeenaes 2 4 2 4 Running a Simulation Interactively eee eee ceeeeeeeeeeeeecaeeaeceesaeeseenaes 2 6 2 5 Measuring Reaction Forces eee eeeesecesceseceseceseceeecaeecaeeeseseeeeneseaeeeeeensees 2 9 2 6 Visualizing Dynamics With Vectors ese cseeereeeeeeseeeeeeeeeeeeeeseeeeeees 2 11 Display the Acceleration of the Connecting Rod eee eee 2 11 Make the Acceleration Vector More Visible 2 12 2 7 Fine tuning the Simulation eee cee ceee cee cneeceeecaeecaeesaecaeesaeeeaeeeaeens 2 14 Convert the MOtor ra os aee eo coschsa cosets oo eE oE Ee EEE pitas EENE ogres 2 14 Attach a Force Load cs evince htt epee ta eee 2 15 Modify the Force to Simulate Realistic Throttle 0 eee eeeeeeee 2 17 Verify the Results cc scale futisdih haieiieiate E uae lala icles 2 18 Exercise 3 Exercise 4 Exercise 5 Exploring CAD Integration and ASSOCIALIVILY ssscseseessessssnneeeees 31 3 1 Exporting a CAD Modelen ni cuates bh vatec
10. Active B Rigid Joint Rotate Around Revolute Joint CX CY CZ Spherical Joint ehom Can i Rigid Joint on Slot Indicates the rotation axis Revolute Joint on Slot Spherical Joint on Slot m Linear Actuator amp Revolute Motor No axes Bod r Slide Along E af As Figure 4 13 illustrates each constraint that limits any degree of freedom shows you the free axis in terms of rotation and or translation In the case of this motor the Properties window shows that the motor allows rotation in the z axis 4 12 Exercise 4 Creating a Piston Model Figure 4 14 Properties Window Motor Page for Motor 7 Click the Motor tab in the Properties window Properties of constraint 4 Revolute Motor x Appearance Constraint Color Motor Active r Motor Type C Orientation Angular Velocity Angular Acceleration Specify angular velocity here C Torque Yaeko U y y coord 3 z axis Specification is expressed in the z axis of Coorof3 Figure 4 14 illustrates that the angular velocity specification is expressed in the z axis of Coord 3 one of the two overlapping Coords constituting the motor By modifying the position and the orientation of Coords you can create a full range of constraints For more information please see the Working Model 3D User s Manual Specifying the Motor Function You will specify the motor s performance characteristics through the Properties
11. Edit toolbar The Create Constraint window appears as shown in Figure 4 18 Note that the body names appear as previously customized in the window so that you can easily verify the bodies and Coords you are attaching are correct Create Constraint ix Rigid Joint from eoord 7 x Revolute Joint Spherical Joint of conrod z 8 Rigid Joint on Slot gt Revolute Joint on Slot to ooo E Spherical Joint on Slot of erankshat Linear Actuator amp Revolute Motor Rod C Join bodies in place move coord 7 to coord 6 Rope Split constraint Don t move anything 4k Separator Join move con_rod to crankshaft Linear Spring D amper C Face to face move con_tod and flip coord 7 o Revolute Spring D amper Create 4 Choose Spherical Joint as the constraint type As discussed in 4 3 Attaching a Motor to the Crankshaft read the first few lines of the window as a complete sentence Create a spherical joint from coord 7 of con_rod to coord 6 of crankshaft Working Model 3D automatically selects the remaining options depending on the objects you selected 5 Click the option Join move con_rod to crankshaft see Figure 4 18 6 Click the Create button in the window The Create Constraint window closes The connecting rod is moved to the crankshaft and a spherical joint icon appears at the attachment point as shown in Figure 4 19 4 18 Exercise 4 Creating a Pi
12. Export Video dialog appears Figure 1 17 Note that Working Model 3D automatically defines the first and last frame numbers according to the existing simulation history Figure 1 17 Export Video Dialog 1 10 Exporting a Video for Windows AVI File Export Video Save in Working Model 3D x c File name conDRoP Save as type Video for Windows Files avi x Cancel First frame fo Last frame 95 Include Meter z Options 3 Type COINDROP in the File name edit box 4 Click Save 1 19 Working Model 3D starts to run each frame to export After the last frame a dialog appears to report that exporting has finished Working Model 3D saves an AVI file exactly the way the running simulation appears in the document window including the pixel size of the window However the toolbar menus tape controls status bar and coordinates bar are not saved in the AVI file To play back the AVI file simply double click on the AVI file from the Windows File Manager or Explorer You can start stop or pause the video with the controls in the video window as shown in Figure 1 18 1 20 Exercise 1 Simulating a Dropping Coin Figure 1 18 AVI File Playback COINDROP Of x NOTE The Windows Media Player may not handle very large AVI files If you experience a problem while playing back try the Video for Windows export again with a reduced window size or number of frames 1 11 Hints
13. FIN vs t s lt i gt coord 30 Coord 10 lt 2 coord 33 Coord lt gt coord 35 Coord 2s coord 36 s coord 39 lt gt coord 41 is coord 42 Coord Coord Coord Coord coord 44 Coord Coord 3 ional Input Connections to constraint 34 constraint 34 IE constraint 34 force on coor output 43 constraint 34 force on coord 32 4 Click the Run bution in the Tape Player Control gt As the simulation runs the values of the x y and z components and the total constraint force between the piston pin and the connecting rod is plotted in the meter window Notice how Fx and Fy oscillate as the crank rotates through a full stroke as shown in Figure 2 10 constraint 34 force on coo i ES Fx Fy Fz IFI N vs t s 1 Figure 2 10 Constraint Force Meter Window 0 8 0 6 0 4 0 2 0 0 2 0 4 0 6 tee 2 6 Visualizing Dynamics with Vectors 2 11 NOTE Your results may not match Figure 2 10 The appearance of the plots depends upon the Motor Rotational Velocity that you select with the input slider 5 Click the Stop button then reset the simulation by clicking the Reset button The piston assembly returns to the initial position 6 Click the close box in the meter window The meter is still available in the Object List but it is temporarily hidden from view You can redisplay the meter by double clicking it in
14. body 1 A Ground Collision Icon 1 5 Running the Simulation You are now ready to watch the coin drop and hit the table 1 Click the Run button in the Tape Player Control at the bottom left corner of the document window The coin falls hits the table and bounces a few times Figure 1 11 The Frame Counter and Time Meter also located at the bottom of the window inform you of the progress 1 6 Adding Shading to the Bodies 1 11 Figure 1 11 e Working Model 3D Untitled1 BEE er Con 6 File Edt View Wold Object Gid Measure Tools Window Help le x ng nisal selel el S s olela ee m ekee el olelalelslele Frame Counter Time Meter eE J For Help press F1 Frame 17 Time 0 34s 7 tae 2 Click the Reset button in the Tape Player Control The coin returns to its original position 1 6 Adding Shading to the Bodies Working Model 3D has a built in rendering capability to add a far greater realism to the image compared to the wireframe rendering 1 Choose Shaded in the View menu The green coin and the grey Ground Plane appear shaded as shown in Figure 1 12 1 12 Exercise 1 Simulating a Dropping Coin Figure 1 12 Shaded Image Ez 2 Click the Run button in the Tape Player Conirol The simulation runs with the shaded coin 3 Click the Reset button after running for a few dozen frames NOTE When two objects become very close to each other you may notice br
15. button Notice how the coordinates bar shows the extent of the circle as shown in Figure 1 3 1 4 Exercise 1 Simulating a Dropping Coin Figure 1 3 Drawing a Coin e Working Model 3D Untitled1 olx Eile Edit View World Object Grid Measure Tools Window Help l x elsl lela ele k el elal ele Delta xee e ENN ca Coordinates bar shows the circle extent By clicking a second time you have completed the profile of the cylinder You will now extrude the circle up or down to complete the cylinder 4 Move the mouse upwards slightly to extrude the circle Click the mouse button once again to complete Again notice how the mouse movement snaps to the grid units resulting in a jumpy shift of the cylinder height 1 3 Positioning the Coin 1 5 Figure 1 4 Completed Coin Local Coordinate System for the Cylinder Also note that the coin has a set of axes to represent the local coordinate system as shown in Figure 1 4 The coordinate origin coincides with the geometric center of the body 1 3 Positioning the Coin Initially the coin rests on the xy plane You will move the coin away from the plane and rotate it slightly 1 Double click the coin in the document window or in the Object List that runs along the left edge of the window The Properties window appears as shown in Figure 1 5 This window floats above other windows and displays information abo
16. coordia Fe Spherical Joint on Slot of body 1 E 4 Linear Actuator amp Revolute Motor T Rod C Join bodies in place move coord 4 to coord 3 Rope Split constraint Don t move anything H KSeparator Join move body 2 to body 1 Af Linear Spring Damper C Facetofi body 2 and fli 4 og Revolute Spring Damper 1 ace move bodia ip conda Create 4 Select Revolute Joint as the joint type in the list of constraints The Create Constraint window is a versatile tool to create a constraint between a given pair of Coords The window presents different options depending on the type of objects that are currently selected The window is best understood when you read the first few lines of the window as a complete sentence In our case the dialog reads Create a Revolute Joint from coord 4 of body 2 to coord 3 of body 1 The bottom half of the Create Constraint window provides several options For this exercise 5 Choose the option labeled Join move body 2 to body 1 The option indicates that body 2 the rotation axle will be moved to body 1 the flywheel so that the two Coords will be aligned 6 Click the Create button located at the bottom of the window The rotation axle is moved to the flywheel and the revolute joint icon appears at the attachment points as shown in Figure 5 15 5 4 Attaching the Flywheel to the Rotation Axle 5 15 Figure 5 15 Assembled Gyroscope
17. flywheel 1 Click the Coord tool on the Sketch toolbar 2 Click anywhere on the flywheel A Coord appears with a red circle and the coordinate axes When selected a Coord displays its triad with labels for x y and z axes as shown in Figure 5 11 To obtain a clear view of the Coord you may wish to use the Zoom In Out or Rotate Around tools Figure 5 11 Coord on a Flywheel Figure 5 12 Properties Window Position Page for Coord 5 4 Attaching the Flywheel to the Rotation Axle 5 11 Double click the Coord in the drawing window or the Object List The Properties window appears Ifthe position page is not displayed click the Pos position tab The Position page is displayed as shown in Figure 5 12 Appearance Pos Vectors word Pos Color Position and Orientation in Enter these values I Anchored Verify that the position and orientation of the Coord are x y z 0 0 0 125 and Rx Ry Rz 0 0 0 If the values appear differently type these values in the window to position the Coord precisely 5 12 Exercise 5 Modeling a Gyroscope Top The position and orientation of the Coord are expressed in terms of the coordinate system of the flywheel because the Coord is attached to it Atiaching a Coord to the Rotation Axle In this step you will attach another Coord to the rotation axle 1 2 Click the Coord tool on the Sketch toolbar C
18. for Faster Animation Here are some guidelines to speed up the Working Model 3D animation playback and editing e Use a small window size The fewer pixels Working Model 3D needs to draw the faster the rendering becomes The same goes for the AVI file rendering e Use wireframe mode while editing This option is turned on by default under the View menu When you drag or resize objects this option speeds up the editing 2 1 EXERCISE 2 Analyzing a Piston Model This exercise illustrates how you use Working Model 3D to immediately start analyzing the performance characteristics reaction forces collision and part interference and test what if scenarios on a model of a piston assembly It walks you through the full range of analytical features available in Working Model 3D The piston model that you analyze could have been created by e exporting a model from your favorite CAD software For more information on exporting CAD models see Exercise 3 Exploring CAD Integration and Associativity e building a model from scratch in Working Model 3D For more information on building models see Exercise 4 Creating a Piston Model 2 2 Exercise 2 Analyzing a Piston Model 2 1 Opening a Model File 1 Open the file Piston wm3 located in your Program Files Working Model 3D Tutorials Exercise 2 directory The folder path may vary depending on where you installed Working Model 3D The model of the pis
19. of body 1 Cylinder x Appearance Pos vel Material Geomety CM 4 gt Position and Orientation i mm deg Enter orientation here x 0 Rx 0 y jo Ry z 0 Rz World coordinates Body YZ I Anchored 11 Enter the orientation of the cylinder as Rx Ry Rz 0 35 0 The crankshaft is reoriented as soon as you tab out of the Ry field You do not need to close the Properties window to have the changes take effect Assigning a Name to the Crankshaft As you create bodies in a document Working Model 3D automatically assigns a variable name such as body 3 body 4 to each of them Although not necessary for this exercise you will name each body so that you can easily identify them later 1 Click the Appearance tab at the top of the Properties window The Appearance page appears as shown in Figure 4 8 4 8 Exercise 4 Creating a Piston Model Figure 4 8 Properties Window Appearance Page for Cylinder Figure 4 9 Status Bar Identifying Object Properties of body 1 crankshaft x Appearance Pos vel Material Geomety CM alel Name Appearance ferankshaft T Shown T Center of mass shown Type the name crankshaft here T Translucent Color 2 Inthe Name field of the window type crankshaft in the edit box then press the Enter key on your keyboard To see how the custom name helps you in identifying bodies simply hover the m
20. simulation through meters The target model is a simple piston engine model consisting of a crankshaft a connecting rod and a piston The engine has a skewed crankshaft i e the rotation axis is not orthogonal to the translation axis of the piston therefore the model can only be illustrated in a three dimensional simulator In a conventional internal combustion engine a gas explosion in the chamber pushes down the piston to drive the crankshaft For simplicity however this tutorial exercise calls for a mechanism that is driven by rotating a crankshaft with a motor you can think of the model as a rudimentary compressor or a piston engine being started by a crank motor 4 2 Exercise 4 Creating a Piston Model Figure 4 1 Numbers amp Units Dialog 4 1 Setting Up the Workspace You will first set up the unit system in the Working Model 3D document in order to accommodate small mechanisms such as a piston engine The default unit system employs the SI unit system where distance is measured in meters You will change the distance unit to millimeters while leaving all other units such as time and mass intact Setting Up the Units To change the unit system 1 Choose the Numbers amp Units in the World menu The Numbers amp Units dialog appears Figure 4 1 By default the SI degrees unit system is chosen Numbers amp Units x Numbers C Fixed Point C Floating Point Automatic Digits g Distanc
21. static drawing or two dimensional model 5 2 Exercise 5 Modeling a Gyroscope Top 5 1 Setting Up the Workspace In this exercise you will use the English unit system as you build the gyroscope model Changing the Unit System To change the default SI unit system to the English unit system 1 Choose Numbers amp Units in the World menu The Numbers amp Units dialog appears as shown in Figure 5 1 Figure 5 1 Numbers amp Units Dialog r Numbers i C Fixed Point Cancel C Floating Point D me igi Automatic ei English slugs SI degrees SI radians Energy feu x Power HP sd Frequency f none x Velocity none gt Rot Vel Distance fir Mass Time Rotation Force Unit System List 2 Select the item English pounds from the Unit System list 3 Click OK All the measurements in the simulation will be done in the English unit system for the remainder of the exercise using inches for distance pounds for mass and seconds for time Figure 5 2 The Edit Grid 5 1 Setting Up the Workspace 5 3 Modifying the Edit Grid Although the unit system is changed the default workspace is scaled rather large for a small mechanism such as a gyroscope top whose flywheel diameter will be approximately three inches Each component would appear too small to manipulate In this step you will modify the workspace to a more appropriate scale 1 Choose Show Gr
22. tele lt l elella w a fk eael of 2 olsl lelsle le Y Untitled1 2 olx E UERR Name constraint 5 Nh constraint 5 constraint 7 4 constraint 7 coord 3 s coord 6 coord 4 coord 13 constrai lt b coord 3 body 1 constraint 5 coord 3 am For Help press F1 3 Click the Run button in the Tape Player control Run the simulation for approximately two hundred frames Observe that the gyroscope exhibits the precession while the flywheel undergoes a rapid rotation 4 After running for about 200 frames click the Reset button Working Model 3D resets the simulation to the initial condition but the simulation data is still stored in memory 5 Click the Run button again Note that the simulation seems to run much faster the second time around Working Model 3D stored the simulation history from the previous run and it is simply playing back the data As soon as the tape player control s frame indicator reaches the rightmost edge Working Model 3D will need to recompute and the apparent speed of the simulation slows down 6 After running for about 200 frames click the Reset button Figure 5 24 Properties Window Vectors Page for the Rotation Axle 5 8 Displaying the Angular Velocity Vector 5 25 5 8 Displaying the Angular Velocity Vector Working Model 3D allows you to visualize the dynamics of a simulation by displaying vectors as the s
23. thicken as shown in Figure 1 7 to indicate that the body is selected and the local coordinate system becomes visible When you deselect a body the edges become thin again and the local coordinate system becomes invisible When you move the mouse over a body the bounding box becomes visible to show which body will be selected if you click now 1 8 Exercise 1 Simulating a Dropping Coin Stepping Back in View Currently your document window shows the coin and a portion of the Edit Grid To observe the dropping coin later you will step back to get a bigger picture 1 Click the Zoom In Out tool on the View toolbar The mouse cursor turns into the Zoom icon 2 Click near the origin of the coordinate axes hold down the mouse button then move the mouse up and down Observe that the document view changes as if you are stepping backward as you move the mouse up and forward as you move the mouse down 3 When the entire Edit Grid is visible release the mouse button Your view may resemble Figure 1 8 If the Edit Grid does not appear to be centered proceed to the next step Figure 1 8 Centered Edit Grid l Edit View World ae Grid Measure Tools oa Help z lel x ojala e aA esoe w e fk eae e 4 If the Edit Grid does not appear to be centered click the Pan tool The mouse cursor turns into the Pan icon Figure 1 9 Ground Plane 1 4 Creating a Ground Plane 1 9 5 C
24. 0 frames per second 5 2 Creating the Flywheel The simple gyroscope in this exercise consists of a single flywheel and a rotation axle In this section you will create the flywheel 1 Click the Cylinder tool on the Sketch toolbar 2 Position the pointer anywhere on the Edit Grid and click the mouse button Then move the mouse to expand the circle As you move the mouse a circle appears on the Edit Grid 3 Move the mouse around until the diameter of the circle reaches 3 inches Click the mouse button Notice how the coordinates bar shows the extent of the circle as shown in Figure 5 6 Figure 5 6 Drawing the Flywheel 5 3 Creating the Rotation Axle 5 7 5 File Edit View World Object Grid Measure Tools Window Help l x ojsjmj e ol elsen ele el eoe el alela elele Name Type Cylinder Coordinates bar shows the circle extent Connections to body 1 body 1 4 Move the mouse upwards slightly to extrude the circle When the Coordinates bar shows that the thickness reaches 0 25 inches click the mouse button once again to complete the cylinder 5 3 Creating the Rotation Axle You can also specify a body s geometry by describing its attributes in the Properties window You will do so in this step as you create another cylinder for the rotation axle 1 Click the Cylinder tool on the Sketch toolbar 2 Click once on the Edit Grid then press the Ent
25. 1 PistorHeacPushedJpanulled Down by the Connecting Rod 8 Click the Stop bution Your model of the motion of the piston assembly is now complete 3 30 Exercise 3 Exploring CAD Integration and Associativity 3 5 Using CAD Associativity You ve put a lot of work into adapting the CAD model to accurately simulate the motion of the piston assembly What happens if the CAD model changes When you re export the CAD model any changes to it are automatically incorporated into your simulation of the motion All of the changes and enhancements that you have already made in the simulation are left unchanged Change the Connecting Rod Length and Re export the CAD Model In this step you will re export the model to Working Model 3D When you return to Working Model 3D the changes you made will automatically be incorporated into your simulation of the motion A Mechanical Desktop only A1 Reopen the Piston model in your CAD software A2 Change the length of the Connecting Rod part from 15 cm to 25 cm If needed refer to your CAD software User s Manual or online help for instructions on how to change the length of the connecting rod part A3 Choose Simulate Motion in the Motion menu Working Model for Mechanical Desktop re exports the piston assembly components and constraints When the process is done the Working Model 3D program reopens the linked model as shown in Figure 3 32 3 5 Using CAD Assoc
26. 1 Polymesh PISTON PIN 1 Polymesh Concentric Revolute Concentric2 Revolute Concentric4 A Concentric Revolute Revolyte a gt 3 12 Exercise 3 Exploring CAD Integration and Associativity 3 2 Anchoring the Assembly Based on the constraints and geometry in the CAD model Working Model 3D may anchor some parts to the background when it creates the linked model The first step in simulating the motion of the piston assembly is to make sure that it is properly anchored e If no bodies in the assembly are anchored the piston is floating in space and gravity will cause it to fall when you run the simulation e If too many bodies are anchored the piston won t be able to move appropriately when you run the simulation A Mechanical Desktop only When Working Model 3D imports the piston assembly from Mechanical Desktop it doesn t anchor any bodies In order for the piston to move properly you must anchor the body named ANCHOR_1 COMP1_1 to the background A1 Double click ANCHOR_1 COMP1_1 in the Object List The Properties window for ANCHOR_I COMP1_1 appears A2 If necessary click the Pos tab in the Properties window then click the Anchored box to put a checkmark in it as shown in Figure 3 15 3 2 Anchoring the Assembly 3 13 Figure 3 15 P roperties Window Appearance Pos vel Material Geometry CM alel Position Page for the Anchor P
27. 15 Constraint Settings Dialog Appearance Constraint Color Active 2 7 Fine tuning the Simulation 2 15 The constraint s properties are displayed in the Properties window 2 Click the Constraint tab 3 Select Revolute Joint from the list of available constraints as shown in Figure 2 15 The motor is replaced by a revolute joint Properties of constraint 10 Revolute Joint x m Rigid Joint Rotate Around CF Revolute Joint so BS De Spherical Joint incre Ca 8 Rigid Joint on Slot 0 Revolute Joint on Slot Slide Along R Spherical Joint on Slot cx cy rez m Linear Actuator amp Revolute Motor No axes Attach a Force Load Next you will attach a force load to the top of the piston to simulate the force generated by a gas explosion in a cylinder chamber 1 Click the Toggle Wireframe button in the View toolbar The drawing window changes to a shaded rendering which will make it easier to complete the next steps Click the Rotate Around tool in the View toolbar or press T on the keyboard so that you can see the top of the piston head Your view should be similar to Figure 2 16 2 16 Exercise 2 Analyzing a Piston Model Figure 2 16 Top of the Piston Head Figure 2 17 Properties Window Force Page 3 Click the Force tool in the Sketch toolbar 4 Click the mouse pointer at the top of the Piston near the center The precise location of the attachment is no
28. 4 10 Taking Measurements The simulation model you have just created serves as a powerful visualization tool to observe the general motion of your mechanism Working Model 3D can take you further by allowing you to take numerical measurements on various aspects of your simulation In this exercise you will create a meter to measure the angular velocity of the crankshaft cylinder as well as the forces experienced by the joint between the piston and the connecting rod To create a meter to measure the angular velocity of the crankshaft 1 Select the crankshaft cylinder in the document window or the Object List 2 Choose Angular Velocity in the Measure menu A meter with the title Angular Velocity of crankshaft appears as a separate window as shown in Figure 4 31 S Angular Velocity of crankshaft OL x Ws deg s Wy deg s Wz deg s IWI deg s vs t s Note that when the meter window is active the toolbar icons for tools which do not apply to meters are disabled appear grayed out By default the angular velocity meter shows plots for angular velocities in x y and z axes as well as the magnitude In this simulation the crankshaft rotates with its z axis fixed so you are only interested in observing or the z component of the angular velocity 3 Select the meter in the Object List then choose Properties in the Edit menu 4 10 Taking Measurements 4 31 The Properties window for th
29. 6 New Input Slider for Rotational Velocity of Motor 2 4 Running a Simulation Interactively 2 7 The revolute motor is selected even though it may not be visible in the drawing window Choose Create Input in the Object menu then choose Rotational Velocity in the submenu that appears An input slider window appears above the drawing window with the title Rot Velocity of constraint 10 as shown in Figure 2 6 File Edit View World Object Grid Measure Tools Window Help lal x oela see 9 eltel el eese le olelalalslels Name Anchor_par_1 Connecting Ro amp Crank_par_1 Crank_par_2 Crank_Pin_par_1 amp Piston_Head_pa Piston_Pin_par_1 constraint 16 constraint 22 constraint 31 constraint 34 constraint 40 a constraint 10 constraint 25 constraint 28 od coord 8 s coord 14 lt coord 19 Polymesh Polymesh Polymesh Polymesh Polymesh Polymesh Polymesh Revolute Revolute Revolute Revolute Revolute Revolute Rigid Joint Rigid Joint Base Coor Base Coot Base Coor E eE Select the input slider then choose Properties in the Edit menu The input slider s properties appear in the Properties window Click the Appearance tab in the Properties window then enter Motor Rotational Velocity as the name for this input slider as shown in Figure 2 7 The new name appears as the title of the in
30. AD Integration and Associativity Figure 3 18 Properties Window Constraint Page for Revolute Motor A Mechanical Desktop only A1 Select ANCHOR_1 COMP1_1 in the Object List The Connections List displays a list of the objects connected to this body A2 Double click constraint 65 the revolute joint that connects ANCHOR_1 COMP1_1 to CRANK_1 COMP1_1 The Properties window for constraint 65 appears A3 If necessary click the Constraint tab in the Properties window Then select Revolute Motor for the list of available joint types as shown in Figure 3 18 The revolute joint is changed into a revolute motor Properties of constraint 63 Revolute Motor x Appearance Color Constraint Active Motor l B Rigid Joint al gt Rotate Around s s go Noares C A Revolute Joint Spherical Joint Rigid Joint on Slot 0 Revolute Joint on Slot Spherical Joint on Slot Linear Actuator amp Revolute Motor Rod r Slide Along Va iz No axes A4 Click the Motor tab in the Properties window Then choose Angular Velocity from the list of Motor Types A5 Enter 500 as the value for angular velocity of this Revolute Motor as shown in Figure 3 19 You can close the Properties window now Figure 3 19 Properties Window Motor Page Properties of constraint 65 Revolute Motor x Appearance Color Constraint Active
31. Motor r Motor Type C Orientation cK 7 3 3 Adding a Motor 3 17 C Torque Value 500 deg s coord 19 z axis B Solid Edge only B1 B2 B3 Select ANCHOR PAR 1 in the Object List The Connections List displays a list of the objects connected to this body Double click constraint 63 the revolute joint that connects ANCHOR PAR 1 to CRANK PAR 1 The Properties window for constraint 63 appears If necessary click the Constraint tab in the Properties window Then select Revolute Motor for the list of available joint types as shown in Figure 3 20 The revolute joint is changed into a revolute motor 3 18 Exercise 3 Exploring CAD Integration and Associativity Figure 3 20 Properties Window Constraint Page for Revolute Motor Figure 3 21 Properties Window Motor Page Properties of constraint 63 Revolute Motor x Appearance Color Constraint Active Motor m Rigid Joint Rotate Around Revolute Joint Cy C Spherical Joint RE EA Rigid Joint on Slot O Revolute Joint on Slot Spherical Joint on Slot gt Linear Actuator amp Revolute Motor Rod No axes Slide Along f EEY EZ B4 Click the Motor tab in the Properties window Then choose Angular Velocity from the list of Motor Types B5 Enter 500 as the value for angular velocity of this Revolute Motor as sh
32. Point EA English pounds iaon Digits RO English slugs Automatic SI degrees SI radians Distance mm Energy in z Choose Mass ka E Power w z ipm Time s 7 Frequency none x Rotation deg Velocity none z Force N x Rot Vel ES 4 Choose rpm in the Rot Vel pull down list 5 Click OK to close the Numbers amp Units dialog 6 Run the simulation As the simulation runs the angular velocity W grows to approximately 600 rpm then levels off as shown in Figure 2 20 5 Angular Velocity of Crank_par_1 Of x Figure 2 20 Angular Velocity Meter Ws Wy W2 WI rpm vs t s 600 400 200 0 200 400 600 2 20 Exercise 2 Analyzing a Piston Model 3 1 EXERCISE 3 Exploring CAD Integration and Associativity This exercise illustrates how you can add motion to a model that has been created in a CAD software package You can create CAD assemblies in such a way that they map into Working Model 3D very cleanly When you design assemblies with motion in mind they can be imported easily and their motion can be simulated immediately In this exercise you will add motion to an assembly that has been fitted together with no regard to motion Although you will have to clean up a few constraints in the imported CAD model Working Model 3D makes it easy to simulate the motion of the assembly 3 2 Exercise 3 Exploring CAD Integrati
33. RE eee EEE BT Custom colors ee a Hue 0 Red 255 Se Beene ea Sat 240 Green 0 Defne Custom eolas gt gt ColorlSolid um 120 Bue f0 Add to Custom Colors Choose a bright red color and click OK to close the Color dialog The acceleration vector will now be displayed in red Click OK to close the Vector Settings dialog Click the Run button in the Tape Player Control 2 14 Exercise 2 Analyzing a Piston Model Figure 2 14 AcceleratioWectoo onnecting Rod tee As the simulation runs note that the acceleration vector attached to the connecting rod switches sides because the acceleration switches direction halfway through the full cycle as shown in Figure 2 14 Acceleration i Vector i 7 Click the Stop button then reset the simulation by clicking the Reset button The piston assembly returns to the initial position 2 7 Fine tuning the Simulation Up to this point the piston mechanism has been driven by a motor constraint attached to the crankshaft In a more realistic simulation of an internal combustion engine a throttle force generated by a gas explosion in a cylinder chamber would push the piston down to torque the crankshaft In this last step you will fine tune the model to simulate this more realistic scenario Convert the Motor First you will convert the motor to a revolute joint 1 Double click the revolute motor constraint 10 in the Object List Figure 2
34. S RE Ae E 3 2 3 2 Anchoring the Assembly eeseeeeseeeeseeseseresesrerrsreereserrrssrerrserrenreseeersreeresee 3 12 3 3 Adding MOtoro ceesevvesacecies yes tnedsth scenes ch E es dae EOE E EEEN E eles 3 15 3 4 Adjusting the JOINts ie enra e e E a TEES 3 20 Constrain the Motion of the Piston Head ssseeseeeeeesseeesseeerrserersreeeees 3 27 3 5 Using CAD ASsociativit yo eee eeceeeceseeeeeesseeseceseceseeecsseensecaesasenas 3 30 Change the Connecting Rod Length and Re export the CAD Model 3 30 Creating a Piston MOCelI s sssssssssssssssssseseeseesessssssununnaneeeseesessssesnnase 4 1 4 1 Setting Up the Workspace renren eian n E E A i 4 2 Setting Up the Units ee eae aere E aR EDET ES ESEA Eei 4 2 Setting Up the Edit Grd aerorose estort en ures Tap eieae Ones aeS DENES EFESE suede EROS 4 3 4 2 Creating the Crankshaft eee eene aee ee e ae EE EIRA 4 4 Assigning a Name to the Crankshaft eseeseeeseeeeeeeeeeeseeresesreersreersreereees 4 7 4 3 Attaching a Motor to the Crankshaft eee eeeeeeceeceeseeeeceseceseenseeseenaes 4 8 Specifying the Motor FUNCtiON 0 0 ce ceeeesseeeesecseeecnereecseeeceaeceeeeeenees 4 12 44 Creating the Connecting Rod oie eee eeeeeecneeeseceeaeceseeaeceesseseeenseeeeees 4 14 4 5 Attaching the Connecting Rod to the Crankshaft eee ee eeeeeeereeeees 4 15 Creating Attachment Points ce eeeeeeeceeeeeeeceecesecaeceaeeneecaeeeae 4 15 Creating a Spherical Joint sisese sonestsesevoi
35. Show Coords n Hoaess Close About Help B5 Click the Build Model button Working Model for Solid Edge re exports the piston assembly components and constraints When the process is done the Working Model 3D program reopens the linked model as shown in Figure 3 34 a Working Model 3D Piston BEE File Edit View World Object Grid Measure Tools Window Help le x olsa Hee S 2 G8 a al e amp ANCHOR PAR 1 Polymesh CONNECTING Polymesh amp CRANK PIN PA Polymesh elsia sle k eee el CRANK PAR 1 Polymesh CRANK PAR 2 Polymesh PISTON HEAD Polymesh PISTON PIN PA Polymesh constraint 65 Revolute constraint 69 Revolute constraint 71 Revolute constraint 75 Revolute z a saran el Connections to constraint 59 PISTON HEAD PAR 1 constraint 59 lt coord 31 coord 29 3 5 Using CAD Associativity 3 33 Your changes to the CAD model are reflected in Working Model 3D The length of the connecting rod has been changed S C SolidWorks only C1 C2 C3 Reopen the Piston model in your CAD software Change the length of the Connecting Rod part from 150 mm to 250 mm If needed refer to your CAD software User s Manual or online help for instructions on how to change the length of the connecting rod part Choose Simulate Motion in the Motion menu Working Mode
36. Working Model 3D Version 3 0 for Windows 95 and Windows NT Tutorial Guide Knowledge Revolution Mane Information in this document is subject to change without notice and does not represent a commitment on the part of Knowledge Revolution The software described in this document is furnished under a license agreement or non disclosure agreement The software may be used or copied only in accordance with the terms of the agreement It is against the law to copy the software on any medium except as specifically allowed in the license or non disclosure agreement No part of this manual may be reproduced or transmitted in any form or by any means electronic or mechanical including photocopying and recording for any purpose without the express written permission of Knowledge Revolution Copyright Knowledge Revolution 1997 All rights reserved Published and printed in the U S A Knowledge Revolution Working Model the Working Model logo Smart Editor Working Model Basic Working Model 3D AutoMotion AutoMotion 3D Motion Edge and MotionWorks are trademarks of Knowledge Revolution Working Model is a registered trademark of Knowledge Revolution Microsoft and Windows are registered trademarks of Microsoft Corporation Video for Windows is a trademark of Microsoft Corporation ACIS is a registered trademark of Spatial Technologies Incorporated AutoCAD and Mechanical Desktop are registered trademarks of Autodesk Incorporate
37. are basic objects to construct constraints in Working Model 3D Physically a Coord is a point element with a coordinate system attached Therefore a Coord has position and orientation To visualize a Coord simply click the red circle around the motor icon Notice that a set of coordinate axes appear and that the red circle is a representation of the xy plane of the Coord You may wish to use the Zoom tool to get a closer look All constraints except for external forces and torques in Working Model 3D consist of a pair of Coords each of which are attached to a body or the background In essence a Coord serves as a medium between a body and the constraint as illustrated in Figure 4 12 Figure 4 12 Concept Construction ofa Constraint Figure 4 13 Properties Window Constraint Page for Motor 4 3 Attaching a Motor to the Crankshaft 4 11 m For constraints such as spring dampers and separators Coords serve as endpoints to define those physical constraints For joints Working Model 3D uses the orientation of the pertinent Coords to determine the constraint conditions For example 5 Double click the motor icon located at the center of the crankshaft or in the Object List The Properties window appears for the motor as shown in Figure 4 13 6 Click the Constraint tab in the Properties window Properties of constraint 4 Revolute Motor x Appearance Color Constraint Motor
38. ated with objects in the Mechanical Desktop model as shown in Figure 3 4 Figure 3 4 CAD Associativity Dialog Figure 3 5 Linke MechanicaDesktofModel Opened in Working Model 3D 3 1 Exporting a CAD Model The following objects are associated with Mechanical Desktop body 1 ANCHOR_1 COMP1_1 body 11 PISTPIN_1 COMP1_1 body 13 PISTHEAD_1 COMP1_1 body 7 CON_ROD_1 COMP1_7 body 9 CRANK_2 COMP1_1 body 5 CRANKPIN_1 COMP1_1 body 3 CRANK_1 COMP1_1 constraint 59 Revolute Joint constraint 69 Revolute Joint on Slot constraint 61 Revolute Joint constraint 65 Revolute Joint on Slot constraint 3 Revolute Joint constraint 63 Rigid Joint constraint 1 Revolute Joint constraint 67 Rigid Joint coord 15 Base Coord coord 41 Base Coord coord 25 Base Coord z Choose CAD Associativity under the Tools menu to see this list again A4 Click OK to close the CAD Associativity dialog The linked model appears in the Working Model 3D window as shown in Figure 3 5 a Working Model 3D Piston Of x Fie Edt View World Object Grid Measure Tools Window Help 18 x Djs lta ele ssleleia vfs fk 4 3 alae 2 2 Yala 4 ANCHOR_1 C0 Polymesh CON_ROD_1 C Polymesh CRANK_1 COM Polymesh CRANK_2 COM Polymesh CRANKPIN_1 C Polymesh PISTHEAD_1 C Polymesh PISTPIN_1 C0 Polymesh constraint 59 Revolute
39. d Solid Edge is a registered trademark of Intergraph Corporation SolidWorks is a registered trademark of SolidWorks Corporation All other products or name brands are trademarks of their respective holders Working Model Inc A Division of Knowledge Revolution 66 Bovet Road Suite 200 San Mateo California 94402 Phone 650 574 7777 Fax 650 574 7541 www workingmodel com Contents Exercise 1 Exercise 2 Simulating a Dropping COIN csssssssssssssssscsssssssssssssssssssssssssesseeseseseeeeen 1 1 1 1 Starting Working Model 3D sinini ntesiet perisis taise 1 2 1 2 Drawing the Com cccci inset ass e rae eR enh Aas Rees EEE E SS 1 3 1 3 Positioning the Comiveccs scs ccssiesssssseesccsdssasbes sessdee lessees seessuebastsenssshessncbstdsvacsons 1 5 Stepping Back in View euii reesei E e E E ERE EEE a 1 8 1 4 Creating a Ground Plane sisser ai apare 1 9 1 5 Running the Simulation eseseeseeeeeseeeesesteersreesesrerrsseerssrrrrnerersrerrssesrenrreesee 1 10 1 6 Adding Shading to the Bodies eseesseeesseeeesesreseseeesssrrrsreerssrerrssreresreeesse 1 11 17 Navigating the World Terora eanna ee wanes rer E EEE bub lu sea EEE IEA EE nts 1 12 1 8 Analyzing the Simulation eee cee ceeesecnse cee caeecaecseecaeetseeeneeaeens 1 15 Displaying a Velocity Vector on the Coin cece ese ereeereeeeeeee 1 15 V9 Saving a Piles ssccscecscssesccesecisessscistdsseusssesssseesesessbesenesssusbapsctvschassiascbonssstesetases 1
40. d on crankshaft to a new coord on the background Therefore the dialog is set up to create a motor between the crankshaft and the background Meanwhile the bottom half of the window provides the only option that reads Join crankshaft in place at center of crankshaft The option indicates that the motor will be attached to the crankshaft at its center and that the crankshaft will not move the body will be joined in place Working Model 3D provides a range of options depending on the constraint type and objects you select before creating constraints Please refer to the Working Model 3D User s Manual for more information 4 Click the Create button in the window The Create Constraint window closes 4 10 Exercise 4 Creating a Piston Model Motor Icon What is a Coord Figure 4 11 Coord and Motor Note that a motor icon appears at the center of the cylinder Also notice that e The motor icon has a green cube around it when it is selected with an axis that shows the plane in which the motor allows rotation e Working Model 3D created a red disk shaped object called a Coord The model actually has two Coords at the same global position where one is attached to the crankshaft and the other to the background Figure 4 11 displays only one of them because the two Coords for the motor are overlapped at this point You may wish to zoom in further to gain a better view of these symbols Coords
41. del using vectors to display key properties as the simulation runs 1 2 Exercise 1 Simulating a Dropping Coin Figure 1 1 Working Model 3D with a Blank document window 1 1 Starting Working Model 3D To start Working Model 3D 1 Launch the Working Model 3D program Working Model 3D starts and presents a blank document window as shown in Figure 1 1 a Working Model 3D Untitled1 BEE File Edit View World Object Grid Measure Tools Window Help la x Hele HA eela ele 4 tlaldle 2 2 agga om A 2 Choose Show Grid in the Grid menu The Edit Grid appears in the window as shown in Figure 1 2 1 2 Drawing the Coin 1 3 Figure 1 2 Th Edit e File Edit View World Object Grid Measure Tools Window Help l j xj j plaja Hee A eeel ele n eae ee 1 2 Drawing the Coin You will create a coin in the document 1 Click the Cylinder tool on the Sketch toolbar The Cylinder tool icon appears indented to show that the tool is currently selected Position the pointer anywhere on the Edit Grid and click the mouse button Then move the mouse to expand the circle As you move the mouse a circle appears on the Edit Grid Note that the circle expands from the center and the dimension of the circle snaps to the grid units Move the mouse around until the diameter of the circle reaches 0 2 or 0 3 meters then click the mouse
42. directory to which you would like to save the file 3 Type COINDROP in the File name edit box Working Model 3D automatically adds an extension WM3 to the filename Therefore the file is saved as COINDROP WM3 4 Click Save The simulation history is saved as well as the model data When you open the file next time you can click the Run button to play back the simulation without waiting for Working Model 3D to compute every frame 1 10 Exporting a Video for Windows AVI File Your Working Model 3D simulation is a great way for people to visualize your ideas To demonstrate the coin drop simulation you can reopen the file at a later time and play it back however you must assume that the Working Model 3D application is available where you want to show the demonstration Instead you can save the simulation file in the Video for Windows format a common format for animation files under Windows and distribute the video file Anyone who has a Windows PC can play back the file In fact Working Model 3D simulations will play back more quickly as Video for Windows movies To export the simulation as a Video for Windows file 1 Using the Pan Zoom In Out and Rotate Around tools arrange the view The Video for Windows file will record the simulation exactly as it appears in the Working Model 3D document window Make sure to prepare the scene before you start exporting 2 Choose Export Video in the File menu The
43. e as shown in Figure 4 4 Properties of body 1 Cylinder x 5 6 Appearance Pos Vel Material Geometry om 4 gt Radius fi mm Height fo mm Number of Facets 16 Characteristic Dimension 10 mm M Automatic Enter the position as x y z 0 0 0 Click the Geometry tab The Properties window displays the Geometry page as shown in Figure 4 5 4 6 Exercise 4 Creating a Piston Model Figure 45 Pr roperties Windo w Geometry Appearance Pos Vel Material Geometry om all Page for the Cylinder Radius E mm Height fio mm Number of Facets fi 6 Characteristic Dimension fi 0 mm M Automatic 7 Enter radius 25 height 10 in the dialog Note that all the numbers are interpreted in millimeters You can use the tab key to move from one field to another 8 Close the Properties window The cylinder is accordingly sized and positioned on the screen see Figure 4 6 Figure 4 6 Crankshaft Sized and Positioned Currently the crankshaft is oriented so that it lies flat on the xy plane You will reorient the shaft so that it is slightly skewed 9 Double click the crankshaft cylinder in the document window or the Object List The Properties window reappears Figure 4 7 Properties Window Position Page for the Cylinder 4 2 Creating the Crankshaft 4 7 10 Click the Position Pos tab The Properties window displays the Position page as shown in Figure 4 7 Properties
44. e m 7 Energy none x Mass kg z Power fw z Time s 7 Frequency none x Rotation deg 7 Velocity J none z Force N 7 Rot Vel none M 2 Set the distance units to millimeters 3 Click the OK button to close the dialog All distance measurements in this document will now be in millimeters Figure 4 2 Grid Settings Dialog 4 1 Setting Up the Workspace 4 3 Setting Up the Edit Grid You will modify the size of the Edit Grid and zoom rate of the document so that they are appropriate for the dimensions of the components you will create To change the Edit Grid size 1 Choose Show Grid in the Grid menu The Edit Grid appears 2 Choose Grid Settings in the Grid menu The Grid Settings dialog appears Figure 4 2 Grid Extents 1e 3 mm e Cancel Grid Snap I Snap to grid 20 mm r Constraint and Coord Appearance r Viewer s Clipping Plane M Automatic Front 10 mm 3 Type 200 into Grid Extents and 10 into Grid Snap edit boxes 4 Click OK to close the dialog Note that the units in the dialog are based on millimeters Working Model 3D automatically scales the document window to accommodate the smaller Edit Grid 5 Click the Zoom In Out tool on the View toolbar 4 4 Exercise 4 Creating a Piston Model Figure 4 3 Document Zoomed In The Zoom tool allows you to zoom into the document with a particular focus The first mouse click becomes your focus for zooming
45. e 2 2 e When you select a body in the Object List or the Connections List all of the constraints and Coords connected to that body are displayed in the Connections List e When you select a constraint in the Object List or the Connections List all of the bodies and Coords connected to that constraint are displayed in the Connections List e When you select a Coord in the Object List or the Connections List all of the bodies and constraints connected to that Coord are displayed in the Connections List NOTE Objects that have been hidden in the drawing appear with dimmed icons in the Object List and Connections List Although they are hidden they are still active in the simulation and you can select them in the lists Podbenesh amp Coneco Ao Pohenesh E Cark px Polpmnesh O Crark_ps_2 Poderech O Cak Pir pai Pobmesh Piston Hesd pa Pohmesh amp Pion Pinos 1 Pohmash im A Sekcted constraint conssari 22 Revobse constears 31 Revobse 5 to constraint 16 Cark px Move this bar amp Cark Pin pa up or down comtsnifi6 Bodies and Coords to resize the coed 4 connected to the Connections coon 5 selected constraint List 2 4 Exercise 2 Analyzing a Piston Model Figure 2 3 Properties Window for constrain 40 1 Select Piston _Head_par_1 in the Object List The constraints and Coords connected to the piston head are displayed in the Connections List 2 Select const
46. e Vectors tab The Vectors page is displayed as shown in Figure 1 14 Properties of body 1 Cylinder x Material Geometry CM Central Inertia Vectors Color alel I Rot Velocity Vector I Acceleration Vector T Rot Acceleration Vector I Force Vector T Torque Vector Click the Velocity Vector box to put a checkmark in it Click the Zoom In Out tool on the View toolbar The mouse cursor changes to the Zoom tool Click anywhere on the coin and drag the mouse downwards to zoom in closer Click the Run button in the Tape Player Control As the simulation runs the velocity vector is displayed on the coin as shown in Figure 1 15 1 17 1 9 Saving a File a Working Model 3D Untitled1 BEES File Edit View World Object Grid Measure Tools Window Help lej x QlQ le Tk Sl lalsd e 2 2 Figure 1 15 Velocity Vector on Coin Distal mle gt yf JOE Time 0 18s 7 Frame 9 fee J D For Help press F1 Click the Stop button then reset the simulation by clicking the 7 Reset button ra 1 9 Saving a File To save your coin drop simulation to a file 1 Choose Save in the File menu The Save As dialog appears Figure 1 16 E Working Model 3D J cel E Figure 1 16 Save As Dialog Save in Filename COINDROP Save as type Working Model 3D Document wm3 x Cancel 1 18 Exercise 1 Simulating a Dropping Coin 2 Choose a
47. e connecting rod and the crank assembly move together like a single rigid body In this step you will adjust the joints to give each the appropriate degrees of freedom Adjust the Joints on the Connecting Rod The connecting rod has been given too many constraints by Working Model 3D In this step you will remove two rigid joints that are currently preventing the true motion between the connecting rod and other assembly parts from occurring A1 Select CON_ROD_1 COMP1_1 in the Object List The Connections List displays the constraints and Coords attached to the connecting rod A2 Select constraint 69 the first rigid joint in the Connections List The Connections list displays the bodies and Coords attached to the rigid joint A3 Hold down the Control key and click on coord 29 and coord 31 the two Coords attached to the rigid joint in the Connections list The rigid joint constraint 69 as well as the two Coords coora 29 and coord 31 should be selected when you are done A4 Press the Delete key The rigid joint and the two Coords are removed from the model A5 Repeat steps A1 thru A4 to remove constraint 73 the other rigid joint and coord 37 and coord 39 from the connecting rod Adjust the Joints on the Crank Pin The crank pin has been given the right number of constraints by Working Model 3D but the joints have been given too much freedom In
48. e connecting rod is sized and positioned accordingly as shown in Figure 4 16 45 Attaching the Connecting Rod to the Crankshaft 4 15 As with the crankshaft you will assign a custom name to this body as well 8 Double click the Connecting Rod The Properties window appears 9 Click the Appearance tab The Properties window switches to the Appearance Page 10 Select the text body 5 in the name field and type the name con_rod Press Enter Again notice how the status bar identifies the connecting rod and the crankshaft as you move the mouse over them 4 5 Attaching the Connecting Rod to the Crankshaft To attach the connecting rod to the crankshaft you will specify the attachment point for the connecting rod on the crankshaft Creating Attachment Points You will create one attachment point on the crankshaft another attachment point on the connecting rod and create a spherical joint based on these two attachment points 1 Click the Coord tool on the Sketch toolbar 2 Click anywhere on the top surface of the crankshaft you will position the Coord precisely in the later steps A Coord appears with a red circle and the coordinate axes 3 Double click the Coord The Properties window appears as shown in Figure 4 17 4 Click the Position Pos tab 4 16 Exercise 4 Creating a Piston Model Figure 4 17 PropertieWvindovPositioPage for Coord Properties of coord 6 x Appearance Color Pos w
49. e meter is displayed as shown in Figure 4 32 4 Click the Meter tab if not already selected Figure 4 32 PI roperties Window for Meter Appearance Meter Axes Label Show Formula n M boyis 2w e a M aM P am e ap e paaa fime 5 Delete Wx Wy and W from the Label column As you remove items from the Label column the formula is also deleted as shown in Figure 4 33 Figure 4 33 P roperties Window for Meter after Appearance Meter Axes Unwanted Plots Removed Label Show Formula yl we Vv boast1 wz You will now create another meter to measure the forces experienced by the spherical joint between the piston and the connecting rod 6 Select the spherical joint constraint 15 between the connecting rod and the piston in the Object List When a spherical joint is selected it shows a green cube with short lines to show the allowable rotations 7 Choose Constraint Force on con_rod express in coord 14 in the Measure menu Another meter window appears 4 32 Exercise 4 Creating a Piston Model Figure 4 34 Properties Window Appearance Page for Meter 8 Select this meter window then click the Appearance tab in the Properties window The Appearance page is displayed as shown in Figure 4 34 Properties of output 17 constraint 15 force on coord 1 E3 Appearance Meter Axes Name Appearance int 15 force on coord 1 4 IV Shown T Automatic name I Position tacked
50. eeneees 5 9 5 3 5 6 Sa 5 8 Coords and Constraints eeeeseeeeeeeseseeesesteeresteresrerrsserrrsserrrnesrentsserresee 5 9 Attaching a Coord to the Flywheel eee eeecesecesecesecesecneeeneeees 5 10 Attaching a Coord to the Rotation Axle eee eeeeceeeeeeceeeeeeeeneeees 5 12 Creating Revolte JOmmts 1 iesccssecccessseessesres e in E sweater test 5 13 Attaching the Gyroscope to the Ground eee ee eeeeeeeeeeceeeeeeeeeeensees 5 16 Tilting the Gy LrOsCOperec acse edecscesescguceds eeseg suees eren vessatuesesvesepensspedsceeects ots 5 16 Creating an Attachment Point on the Ground eee eee eee eeee 5 18 Creating an Attachment Point on the Gyroscope eeeeeeeeseeeteeees 5 19 Creating a Spherical Joint eee eeceeeceseceecesecaecneecaeeeneesaesaeeeas 5 20 Giving Initial Spin to the Gyroscope eee eeeecceeeeeeeeeeeeeseeeseceeecaeenaeeaes 5 22 Running the Simulation eee ee eeceeeeeeceeeceeeceseeeeeeseeeseeeeeeeesseesaeeaees 5 23 Displaying the Angular Velocity Vector cee eeceeeeseeeeceesceeeeeeeeeeensees 5 25 vi 1 1 EXERCISE 1 Simulating a Dropping Coin This first exercise in Working Model 3D introduces you to its most fundamental features modeling and running You will create a model of a coin dropping to the ground then learn about running and stopping a simulation manipulating your view of the model and exporting the simulation to a Video for windows file You will also analyze the motion of the mo
51. el 3D attempts to assemble the bodies again using its quick assembly algorithm If the Assembly Error dialog appears again click the Retry button to use the dynamic assembly algorithm 4 9 Running the Simulation 4 29 Figure 4 30 Sa Working Model 3D Untitled3 BEE Full A bled Piston E ine Eile Edit View Wold Object Grid Measure Tools Window Help lej x y ngi osa see zj elslalaln el fk ellae 2 2 olsl lSlel le con_tod Box amp crankshaft Cylinder Cylinder Revolute Rigid Joint Spherical Spherical Base Coo Base Coor Base Coors fs coord 13 ooa For Help press F1 4 9 Running the Simulation To run the simulation e 1 Click the Run button in the Tape Player Control The simulation starts showing the motion of the piston engine mechanism Note that the Tape Player Control located near the bottom of the application window shows the current frame number ma 2 Let it run for 40 frames or so and click the Reset button on the toolbar Use the Pan Zoom and Rotate Camera tools to obtain different view angles and repeat the simulation Note that the simulation runs much faster the second time around because Working Model 3D stores the simulation time history after the first calculations The history remains in memory until you change the initial conditions 4 30 Exercise 4 Creating a Piston Model Figure 4 31 Angular Velocity Meter
52. ented so that its coordinate system orientation matches that of the global frame Given the X Y and Z angles the body is rotated first by X with the body s x axis fixed in space Then the body is rotated by Y with the body s y axis fixed in space Finally the body is rotated by Z with the body s z axis fixed in space For example if the Properties window of a box has a parameter Rx Ry Rz 20 45 30 then Working Model 3D represents the orientation of the box as shown in Figure 5 18 5 18 Exercise 5 Modeling a Gyroscope Top Figure 5 18 Body XYZ Angle Example kS a 2 Rotated 20 degrees 1 Unrotated apa Al ih Global Frame about the body s x axis 3 Rotated 45 degrees 4 Rotated 30 degrees about the body s y axis about the body s z axis Creating an Attachment Point on the Ground You will attach the gyroscope assembly to the ground using a spherical joint To create the joint you will take steps similar to the ones taken when creating the revolute joint 1 Click the Coord tool on the Sketch toolbar 2 Click anywhere on the Edit Grid away from the bodies A Coord automatically attaches to the xy plane 3 Double click the Coord in the drawing window or the Object List 4 If the Pos position page is not displayed click the Pos tab 5 Enter these values to locate the Coord at the global origin That is X Y Z 0 0 0 and Rx Ry Rz 0 0 0 The Coord immediatel
53. er key on the keyboard A small cylinder appears on the Edit Grid This cylinder also appears as body 2 in the Object List which is displayed along the left side of the drawing window 3 Double click body 2 in the Object List or click the right mouse button and select Properties from the menu that appears The Properties window for the cylinder appears as shown in Figure 5 7 5 8 Exercise 5 Modeling a Gyroscope Top NOTE If the small cylinder body 2 lies entirely within the larger cylinder it is only possible to choose this body from the Object List Figure 5 7 P roperties Window Appearance Vel Material Geometry CM abl Position Page for Rotation Axe Position and Orientation in deg x a Rx fo y jo Ry fo zje Rz fo World coordinates Body X Z I Anchored 4 If itis not already selected click the Position Pos tab then enter the position of the rotation axle as x y z 0 0 0 5 Click the Geometry tab The Geometry page of the Properties window appears as shown in Figure 5 8 Figure 58 P roperties Window Appearance Pos vel Material Geometry om gt l Page for R nAxe Radius fo 125 in Height 4 in Number of Facets fi 6 Characteristic Dimension fo 25 in M Automatic 6 Enter 0 125 into the Radius and 4 into the height edit boxes Note that all the numbers are interpreted in inches 7 Close the Properties window Figure 5 9 Rotation Axle Sized and P
54. g you 2 Click the Coord tool on the Sketch toolbar 3 Click at the bottom surface of the piston near the center If you attached the Coord on a side surface of the piston do not be alarmed you will correct it in the next step 4 Double click the Coord The Properties window appears 5 Click the Position Pos tab and verify that the Coord is attached to the piston and the configuration is given as X Y Z 0 0 12 5 and Rx Ry Rz 0 180 0 If any values are different correct them Creating a Spherical Joint To put together the two Coords each attached to the connecting rod and the piston Figure 4 26 Create Constraint Window 48 Attaching the Connecting Rodtothe Piston 4 25 Select the Coord attached to the connecting rod Hold down the Conirol key and select the Coord attached to the piston If you have trouble selecting these Coords in the document window try selecting them in the Object List Click the Join Create Constraint button on the Edit toolbar The Create Constraint dialog appears Figure 4 26 Create Constraint x Rigid Joint from eoor 3 z Revolute Joint Spherical Joint of con_rod bad Rigid Joint on Slot Revolute Joint on Slot io coorti 4 C Spherical Joint on Slot a riton i J Linear Actuator amp Revolute Motor Rod Rope H b Separator Af Linear Spring Damper o Revolute Spring D amper Join bodies in place move coord 13 to c
55. he process is done the Working Model 3D program opens and displays the CAD Associativity dialog listing the Working Model 3D objects that are associated with objects in the SolidWorks model as shown in Figure 3 13 Figure 3 13 CAD Associativity Dialog Figure 3 14 Linked SolidWorks Mode Opened in Working Model 3D 3 1 Exporting a CAD Model 3 11 CAD Associativity Ea The following objects are associated with Solidworks body 11 PISTON PIN 1 body 5 CRANK PIN 1 body 13 PISTON HEAD 1 body 1 Anchor 1 body 3 Crank 1 body 9 Crank 2 body 7 CONNECTING ROD 1 constraint 61 Concentric1 constraint 73 Concentric5 constraint 71 Parallel2 constraint 63 Concentric2 constraint 65 Revolute Joint constraint 1 Revolute Joint on Slot constraint 79 Rigid Joint constraint 63 Revolute Joint constraint 75 Revolute Joint coord 53 coord 33 Base Coord d Choose CAD Associativity under the Tools menu to see this list again C4 Click OK to close the CAD Associativity dialog The linked model appears in the Working Model 3D window as shown in Figure 3 14 lt Working Model 3D Piston Loli File Edt View World Object Grid Measure Tools Window Help Osi ele ol esee wfe fk eae oe 9 8 a 4 4 Polymesh CONNECTING Polymesh CRANK PIN 1 Polymesh Crank 1 Polymesh Crank 2 Polymesh PISTON HEAD
56. hown in Figure 4 20 e Working Model 3D Untitled3 _ Oy x File Edit View World Object Grid Measure Tools Window Help l x Dieja He n esege eae el olel lalslels yi A con_tod Box crankshaft Cylinder Revolute Spherical Base Coord Base Coord Coord Coord crankshaft constraint 8 lt coord 6 coord mJ Frame 10 Time 0 2s 4 2 After running for a dozen frames or so click the Reset button in the Tape Player Control If the model did not behave as discussed you should review your model A few hints are e Ifthe motor is not rotating you may have forgotten to specify the motor s property Review 4 3 Attaching a Motor to the Crankshaft e Ifthe connecting rod is falling downward you probably have failed to attach it to the crankshaft Review 4 5 Attaching the Connecting Rod to the Crankshaft Debugging a large model is not always an easy task As discussed in this section you should take a moment every once in a while to verify your model s assembly before proceeding 4 20 Figure 4 21 Piston Sized and Positioned Exercise 4 Creating a Piston Model 4 7 Creating the Piston You will now create a piston and fix it in space with a slot joint 1 2 Click the cylinder tool on the Sketch toolbar Click once on the Edit Grid then press the Enter key on the keyboard Double click the cylinder in the docu
57. hree degrees of freedom in rotation Tilting the Gyroscope The gyroscope is currently in an upright position To observe precession in this step you will tilt the gyroscope slightly 1 Double click anywhere on the rotation axle make sure you do not click the flywheel or on body 2 in the Object List The Properties window appears 2 Click the Pos position tab The Position page is displayed as shown in Figure 5 17 3 In the field Ry orientation about the y axis enter 15 Figure 5 17 Properties Window for the Rotation Axie Notes on Body XYZ Angle 5 5 Attaching the Gyroscope tothe Ground 5 17 The gyroscope tilts by 15 degrees about the y axis of the axle Properties of body 2 Cylinder x Appearance Color Pos vel Material Geometry 4 gt Position and Orientation in deg 3 25 Rejo vier a Type 15 here zfos ef World coordinates Body YZ T Anchored Note that the flywheel also tilted by 15 degrees and preserved the revolute joint constraint connecting the rotation axle and the flywheel As a result the entire gyroscope tilted by 15 degrees It is important to understand that the body was rotated about the y axis of the body s frame not of the global frame because Working Model 3D expresses the orientation of a body in Body XYZ angles Body XYZ angles represent the orientation of a body with three parameters X Y and Z angles Initially the body is ori
58. iativity 3 31 Figure 3 32 i i poh cad a el ead in ao eer Ts Grid Measure Tools Window Help ray 6 3D ectea ojele Hee A esee e fk eee ee olelaleleleje ANCHOR_1 CO Polymesh CON_ROD_1 C Polymesh CRANK_1 C0M Polymesh CRANK_2 COM Polymesh CRANKPIN_1 C Polymesh PISTHEAD_1 C Polymesh PISTPIN_1 C0 Polymesh constraint 61 Revolute constraint 65 Revolute constraint 69 Revolute M momote sib FA1 Dannlyta Z f Your changes to the CAD model are reflected in Working Model 3D The length of the connecting rod has been changed B Solid Edge only B1 Reopen the Piston model in your CAD software B2 Change the length of the Connecting Rod part from 150 mm to 250 mm If needed refer to your CAD software User s Manual or online help for instructions on how to change the length of the connecting rod part B3 Save your changes to the Connecting Rod part Solid Edge requires you to save your changes before you can re export the model to Working Model 3D B4 Click the Gyroscope button in the WM3D toolbar 3 32 Exercise 3 Exploring CAD Integration and Associativity Figure 3 33 Working Model tor Solid Edge Dialog Figure 3 34 Changes in the Solid Edge CAD ModeReflectedrWorkingVlodel 3D The Working Model for Solid Edge dialog appears as shown in Figure 3 33 Working Model for Solid Edge x r Working Model 3D I
59. id in the Grid menu The Edit Grid appears in the window as shown in Figure 5 2 lt a Working Model 3D Untitled1 BEE File Edit View World Object Grid Measure Tools Window Help la x oela elel Ael eea ee a eae ee olAlalGlsle e Taa 2 Choose Grid Settings in the Grid menu The Grid Settings dialog appears as shown in Figure 5 3 5 4 Exercise 5 Modeling a Gyroscope Top Figure 5 3 Grid Settings Dialog Grid Extents g in Cancel Grid Snap eme V Snap to arid Size 0 25 in r Viewer s Clipping Plane M Automatic 3 Type 5 into Grid Extents and 0 25 into Grid Snap edit boxes Note that the units in the dialog are based on inches because you selected the English unit system Working Model 3D automatically scales the drawing window to accommodate the smaller Edit Grid 4 Click OK to close the dialog The size of the Edit Grid shrinks on the document as shown in Figure 5 4 5 Click the Zoom In Out tool on the View toolbar The Zoom tool allows you to zoom into the document with a particular focus The first mouse click becomes your focus for zooming 6 Drag downward in the drawing window and release the mouse button when the Edit Grid fills a reasonable portion of your drawing window See Figure 5 4 for an example Figure 5 4 Document Zoomed In 5 1 Setting Up the Workspace 5 5 File Edit View World Object Grid Measure Tools Window Help la
60. imulation runs In this step you will display the angular velocity of the rotational axle to emphasize the precession of the gyroscope 1 Double click body 2 the rotation axle in the Object list The rotation axle s properties appear in the Properties window 2 Click the right arrow in the Properties window to scroll the tabs until the Vectors tab is displayed then click the Vectors tab The Vectors page is displayed as shown in Figure 5 24 Properties of body 2 Cylinder x Geometry CM Central Inertia Vectors Color lt gt Show I Velocity Vector Vv A T Acceleration Vector T Rot Acceleration Vector I Force Vector T Torque Vector 3 Click the Rot Velocity Vector box to put a checkmark in it 4 Close the Properties window 5 Click the Run button in the Tape Player Control As the simulation runs the rotational velocity vector is displayed as shown in Figure 5 25 5 26 Exercise 5 Modeling a Gyroscope Top Figure 5 25 Rotational Velocity Vector Rotational Velocity Vector on Rotation Axle 6 Click the Stop button then reset the simulation by clicking the m4 Reset button The gyroscope returns to the initial position
61. inRod To create a pair of attachment points Use the Rotate Around tool so that you can see the free end of the connecting rod as shown in Figure 4 24 48 Attaching the Connecting Rod to the Piston 4 23 Figure 4 24 Attaching a Coord to the Connecting Rod 2 Click the Coord tool on the Sketch toolbar amp 3 Click at the free end of the connecting rod If you attached the Coord ona side surface of the connecting rod do not be alarmed you will correct it in the next step 4 Double click the Coord The Properties window appears 5 Click the Position Pos tab and verify that the Coord is attached to the connecting rod see Figure 4 25 and the configuration is given as X Y Z 0 35 0 and Rx Ry Rz 90 0 0 If any values are different correct them 4 24 Exercise 4 Creating a Piston Model Figure 4 25 Properties for Coord Attached to the Connecting Rod e Properties of coord 13 x Appearance Color Pos World Pos Position and Orientation mm deg x fa Rx so pua x l Enterthe configuration con_rod coordinates Coord XYZ if different from what is shown here Indicates that the Coord is attached to the con_rod Creating an Attachment Point on the Piston To connect the connecting rod with the piston you will also create an attachment point on the piston 1 Use the Rotate Around tool so that the bottom surface of the piston is facin
62. ing Model for Solid Edge dialog 3 8 Exercise 3 Exploring CAD Integration and Associativity When the process is done the Working Model 3D program opens and displays the CAD Associativity dialog listing the Working Model 3D objects that are associated with objects in the Solid Edge model as shown in Figure 3 9 Fi igure 39 The following objects are associated with Solid Edge CAD Associativity Dialog body 5 CRANK PIN PAR 1 body 13 PISTON HEAD PAR 1 body 1 ANCHOR PAR 1 body 11 PISTON PIN PAR 1 body 3 CRANK PAR 1 body 9 CRANK PAR 2 body 7 CONNECTING ROD PAR 1 constraint 69 Revolute Joint on Slot constraint 67 Rigid Joint constraint 7 Revolute Joint constraint 3 Rigid Joint constraint 65 Revolute Joint constraint 1 Revolute Joint on Slot constraint 9 Rigid Joint constraint 63 Revolute Joint constraint 5 Revolute Joint coord 43 coord 33 Base Coord x Choose CAD Associativity under the Tools menu to see this list again B5 Click OK to close the CAD Associativity dialog The linked model appears in the Working Model 3D window as shown in Figure 3 10 3 1 Exporting a CAD Model Figure 3 10 Linked Solid Edge Model Opened Ee Edt ew Wil bec Git Mesue Toot Welw Hep E in Working Model 3D Osa He Hl eleal se k eese el CONNECTING CRANK PIN PA PISTON HEAD PISTON PIN PA constraint 63 constraint 65 constra
63. int 75 constraint 77 yi Polymesh Polymesh Polymesh Polymesh Polymesh Polymesh Polymesh Revolute Revolute Revolute Revolute 5 S C SolidWorks only C1 Launch the SolidWorks 97Plus program C2 Open the file Piston sidasm located in your Program Files Working Model 3D Tutorials Exercise 3 SolidWorks directory The CAD model of the piston assembly is displayed as shown in Figure 3 11 3 9 3 10 Exercise 3 Exploring CAD Integration and Associativity Figure 11 v SolidWorks 97Plus Piston _ Of x SolidWorks CAD Model File Edt View Insert Motion Tools Window Help 218 of Piston Assembly Disa Bia ale o elelee aalala elelee Piston Marii SR M Plane2 HE M Plane L k Origin E f Anchor lt 1 gt CONNECT 7 amp H Crank lt 2 gt amp PISTON PI 2S PISTON H Og MateGroup1 A f Annotations rer Pa Wea IZ Note that a Motion menu appears in the SolidWorks menubar as shown in Figure 3 12 Figure 312 annie Neon Motion Menu in SolidWorks AE ain C3 Choose Simulate Motion in the Motion menu Working Model for SolidWorks maps the assembly components and constraints into Working Model 3D bodies and joints and creates a new linked model named Piston wm3 in the same directory As Working Model 3D translates the geometry the progress is displayed in the Preparing Simulation dialog When t
64. ity of the crank motor especially about the z axis varies rather dramatically To visualize the spike in the joint reaction force 1 Select the force meter then choose Properties in the Edit menu or double click the force meter window The Properties window displays the meter s attributes 2 Click the Appearance tab then choose the Graph radio button 4 34 Exercise 4 Creating a Piston Model Figure 4 36 Force Meter and History The digital meter changes to the graph format to show the history Note the series of spikes seen in the force meter as shown in Figure 4 36 g constraint 15 force on coord 14 Of x Fx N Fy N Fz N IFI N vs t s 0 200 0400 0 600 0 800 To avoid excessive wear and tear on the components suppose you would like to put a simple control system on the crank motor to smooth the rotation Although this scenario appears rather impractical in real situations this exercise is merely designed to provide examples in Working Model 3D 1 Double click the motor icon located at the center of the crankshaft The Properties window appears to show the motor specification 2 Click the Motor tab if it is not already selected 3 Choose the Angular Velocity radio button then enter the following expression in the Value field 0 2 6 283 body 1 w z A warning may appear to remind you that values in formulas must be expressed in SI units The expression body 1 w
65. j x Osta fle A ekeen vis eee Use the Zoom In Out tool If your Edit Grid does not appear to be quite centered use the Pan tool to shift the view laterally Changing the Animation Step By default Working Model 3D sets the Animation Step as 0 02 second In this step you will make the Animation Step smaller than the default value since the gyroscope model in this exercise involves a flywheel that spins very rapidly 1 Choose Accuracy in the World menu The Simulation Accuracy dialog appears Figure 5 5 5 6 Exercise 5 Modeling a Gyroscope Top Figure 55 Simulation Accuracy Simulation Accuracy Dialog Animation Step r Configuration Error foo0s Sy see Position 0394 in Cancel Orientation A deg Default r Integration Step Fixed Integration Step 0 005 sec Variable Steps per Frame 1 gt Wamings Integrator C Euler approximate fast Kutta Merson accurate Overlap Factor 10 01 Assembly Error 10 0394 in Significant Digits 5 I Inaccurate integration I Initial body overlap I Redundant constraints IV Inconsistent constraints Enter 0 005 here 2 Enter the Animation Step as 0 005 seconds as shown in Figure 5 5 Note that the two edit boxes located together in the Animation Step section of the dialog are inverses of each other An Animation Step of 0 005 seconds corresponds to a frame rate of 20
66. l for SolidWorks re exports the piston assembly components and constraints When the process is done the Working Model 3D program reopens the linked model as shown in Figure 3 35 3 34 Exercise 3 Exploring CAD Integration and Associativity Figure 3 35 Changes in the SolidWorks CAD ModeReflectedrWorkingModel fe Est Yew Wald Obist Gi Mesue Teo Widow Heb six 3D Disa ole AA elelee sE M ekale e olslalelsle ls Anchor 1 Polymesh CONNECTING Polymesh CRANK PIN 1 Polymesh Crank 1 Polymesh amp Crank 2 Polymesh PISTON HEAD 1 Polymesh amp PISTON PIN 1 Polymesh Concentricl Revolute Concentric2 Revolute Concentric4 Revolute Revelite oo M Concent brie Your changes to the CAD model are reflected in Working Model 3D The length of the connecting rod has been changed El GQ All CAD Packages 1 Click the Run button in Working Model 3D s Tape Player e Control Your simulation of the motion of the piston assembly runs with no problems 2 Click the Stop button Working Model 3D preserves and protects your enhancements to the simulation model while giving you the flexibility to change the underlying geometry of the CAD model as needed 4 1 EXERCISE 4 Creating a Piston Model l gt The goals of this exercise are to show you how to create constraints and assemble bodies in Working Model 3D and how to take data from the
67. lick anywhere in the document hold down the mouse button and drag the mouse Observe that the entire scene pans in the direction of the mouse movement 6 Repeat the panning as necessary until your view resembles Figure 1 8 1 4 Creating a Ground Plane You will now create a simple table top for the coin to fall on 1 Choose Ground Plane in the World menu A large flat body appears just beneath the cylinder Figure 1 9 Working Model 3D automatically sizes the Ground Plane based on the maximum x y extent of the bodies in the document The top surface of the plane is always at z 0 Also the Ground Plane is anchored such that it does not move relative to the background Bodies will pass through each other unless you specify that they should collide The following steps will make the coin collide with the table 2 Choose Select All in the Edit menu Both the coin and the ground plane are selected 1 10 Exercise 1 Simulating a Dropping Coin Figure 1 10 Collision Icon in the Connections List 3 Choose Collide in the Object menu The selected objects will now collide when you run Note When you select a body in the Object List that runs along the left edge of the document window the other objects in the simulation that are set to collide with it are displayed in the Connections List with a special collision icon as shown in Figure 1 10 P Ground Box EFbody 1 Cylinder Connections to
68. lick anywhere on the surface of the rotation axle A Coord appears with a red circle and the coordinate axes Double click the Coord in the drawing window or the Object List The Properties window appears If the Pos position page is not displayed click the Pos tab Enter the position and orientation of the Coord as follows x y z 0 0 0 and Rx Ry Rz 0 0 0 Again the position and orientation of the Coord are expressed in the coordinate system of the rotation axle which coincides with the global coordinate frame The Coord appears buried inside the rotation axle as shown in Figure 5 13 Figure 5 13 Coord Positioned Inside the Rotation Axle 54 Attaching the Flywheel to the Rotation Axle 5 13 Creating a Revolute Joint Now that the attachment points are ready you will proceed to create a revolute joint connecting the two bodies 1 Select coord 4 the Coord attached to the rotation axle in the Object List 2 Press the Control key on the keyboard and select coord 3 the Coord attached to the flywheel in the Object List 3 Click the Join Create Constraint button on the Edit toolbar The Create Constraint window appears as shown in Figure 5 14 5 14 Exercise 5 Modeling a Gyroscope Top Figure 5 14 Create Constraint Window E Rigid Joint from coords Revolute Joint Spherical Joint of body 2 z 8 Rigid Joint on Slot Revolute Joint on Slot La
69. lide Along 2 BY Be No axes A4 Repeat steps A1 thru A3 to change constraint 75 the other revolute joint on slot on the crank pin into a revolute joint 3 4 Adjusting the Joints 3 23 g B Solid Edge only Currently all of the parts in the piston assembly move together like a single rigid body In this step you will adjust the joints to give each the appropriate degrees of freedom Adjust the Joints on the Connecting Rod The connecting rod has been given too many constraints by Working Model 3D In this step you will remove two rigid joints that are currently preventing the true motion between the connecting rod and other assembly parts from occurring B1 B2 B3 B4 B5 Select CONNECTING ROD PAR 1 in the Object List The Connections List displays the constraints and Coords attached to the connecting rod Select constraint 67 the first rigid joint in the Connections List The Connections list displays the bodies and Coords attached to the rigid joint Hold down the Conirol key and click on coord 29 and coord 31 the two Coords attached to the rigid joint in the Connections list The rigid joint constraint 67 as well as the two Coords coord 29 and coord 31 should be selected when you are done Press the Delete key The rigid joint and the two Coords are removed from the model Repeat steps B1 thru B4 to remove cons
70. ment window or the Object Manager list Click the Position Pos tab then enter the position as x y Z 0 0 60 Click the Geometry tab then enter the geometry as radius height 20 25 The cylinder is accordingly sized and positioned on the screen see Figure 4 21 If the cylinder appears cut off at the top of your document window click the Pan tool to shift the view To assign a custom name to the piston 6 Double click the piston to open the Properties window Figure 4 22 Create Constraint Window 4 7 Creating the Piston 4 21 7 Click the Appearance tab 8 Click once in the name field and type piston in the edit box Press Enter You will now proceed to attach the piston to the background with a slot joint Attaching the Piston to the Background The piston s motion is restricted to the vertical axis You will attach the piston to the background using a rigid joint on slot 1 Select the piston if it is not already selected 2 Click the Join Create Constraint button on the Edit toolbar The Create Constraint dialog appears as shown in Figure 4 22 3 Choose Rigid Joint on Slot as the constraint type The window presents a single option Join in place Create Constraint ix Rigid Joint from anew coord 7 Revolute Joint Spherical Joint on piston x Rigid Joint on Slot Revolute Joint on Slot Spherical Joint on Slot E Linear Actuator to Jane
71. mulation runs W C SolidWorks only When Working Model 3D imports the piston assembly from SolidWorks it anchors the bodies appropriately No modifications are necessary El GY Sf All CAD Packages 1 Click the Run button in Working Model 3D s Tape Player e Control and let the simulation run for about 100 frames Working Model 3D begins to simulate the motion of the model The piston assembly balances at first then the piston head falls under the effect of gravity Since the piston is almost in equilibrium you will not see any movement at first Figure 3 17 Piston Head Swinging Around the Crank Pin Like a Pendulum ele 3 3 Adding a Motor 3 15 The geometry of the assembly causes the piston head to swing like a pendulum around the crank pin which is held in place by the anchor as shown in Figure 3 17 Since this is the first time the simulation is being run Working Model 3D calculates the dynamics and stores the data 2 Repeat the simulation by clicking the Stop button then the Reset button and then the Run button again The animation is faster this time because the history has already been calculated 3 3 Adding a Motor Currently the piston assembly is moving only in response to the effects of gravity In this step you will change the joint between the anchor and left side of the crank to a motor to simulate the force that drives the motion of the piston 3 16 Exercise 3 Exploring C
72. nical Desktop A WM3D toolbar also appears in the Mechanical Desktop window as shown in Figure 3 2 Working Model for Mechanical Desktop A2 Open the file Piston dwg located in your Program Files Working Model 3D Tutorials Exercise 3 Mechanical Desktop directory The CAD model of the piston assembly is displayed as shown in Figure 3 3 3 4 Exercise 3 Exploring CAD Integration and Associativity Figure 3 3 14 Mechanical Desktop Piston Mechanical Desktop CAD Model J Fie Edit View Assist Design Construct Modify Surface Part Assembly Motion Drawing Help of Piston Assembly Os S P sero Cee tier aee 2 Assembly Scene Drawing Priston WM3D Bp tal i a ke La KS kem E ES EAA s o e B xl Komana OO OOOO CS Target PISTON 119 9324 45 4186 0 0000 SNAF GRID ORTHO OSNAF MODEL TILE A3 Choose Simulate Motion in the Motion menu or click the Gyroscope button in the WM3D toolbar Working Model for Mechanical Desktop maps the assembly components and constraints into Working Model 3D bodies and joints and creates a new linked model named Piston wm3 in the same directory As Working Model 3D translates the geometry the progress is displayed in the Preparing Simulation dialog When the process is done the Working Model 3D program opens and displays the CAD Associativity dialog listing the Working Model 3D objects that are associ
73. oken lines or fuzzy edges Working Model 3D s graphic rendering system is optimized for smooth rapid animation of shaded objects so that it works on both 16 bit and 32 bit systems The graphic irregularity is a byproduct of the optimization and does not affect the simulation computation at all 1 7 Navigating the World This section introduces you to the versatile graphics manipulation capabilities of Working Model 3D You can gain a better understanding of your model when looking at it from various view angles In addition the motion associated with the changing view provides a powerful depth cue especially in the perspective mode because objects appear to move at different rates depending on where they are located in the three dimensional space 1 Click the Pan tool on the View toolbar or press F2 on the keyboard The mouse cursor changes to the Pan tool 1 7 Navigating the World 1 13 Click anywhere in the workspace and drag the mouse to the right As you drag the mouse to the right the view shifts accordingly Press P on the keyboard Pressing P on the keyboard is equivalent to choosing Previous in the View menu Your view jumps back to the previous position Click the Zoom In Out tool on the View toolbar or press F3 on the keyboard The mouse cursor changes to the Zoom tool Click anywhere on the coin and drag the mouse upwards As you move the mouse down the view is zoomed in Moving the mouse up Zo
74. omplex When this occurs Working Model 3D presents an Assembly Error dialog 48 Attaching the Connecting Rod to the Piston 4 27 When the Assembly Error dialog appears you can choose which method you want to use to resolve the problem e Click the Retry button to attempt assembly using a dynamic assembly algorithm e Click Cancel to close the dialog then use the Move tool to position the coords that you want to join closer together Using the Dynamic Assembly Algorithm Follow these steps if you want Working Model to attempt to assemble the bodies using a slower iterative dynamic assembly algorithm 1 Click the Retry button in the Assembly Error dialog A progress dialog appears to show the assembly is in process as shown in Figure 4 29 At the same time the bodies in the model undergo motion to show you the assembly process NOTE If you do not see the progress dialog you may have accidentally split another constraint by mistake In that case choose Select All in the Edit menu and click the Join Create Constraint button in the Edit toolbar Working Model 3D will attempt to resolve all constraints simultaneously In the Join process Working Model 3D is solving the configuration to find the converging solution to satisfy all the constraints Bodies may appear to move away from their respective constraints at first but Working Model 3D soon finds a converging solution that satisfies all the constraint conditions 4 28 E
75. oms out Click the Rotate Around tool on the View toolbar or press F4 on the keyboard The Rotate Around tool becomes selected and a dotted line circle appears around the center of the coin Click anywhere inside the circle and drag the mouse around As you drag the mouse around your view rotates around the center of the circle This tool is a very powerful way to change your view and it also provides useful depth cues through motion Press F on the keyboard Pressing F on the keyboard is equivalent to choosing the menu item View gt Look At gt Front View Your view jumps to a front view of your model 1 14 Exercise 1 Simulating a Dropping Coin Working Model 3D provides six shortcuts to view the model in predefined directions You can access the views in the following directions with the corresponding shortcut key View from Shortcut Key Front positive X Top positive Z Bottom negative Z Fight positive Y Left negative Y T pv zadaj wo 7 You can also set a favorite or Home view and quickly return to it or zoom out to see the entire model with these shortcut keys View Shortcut Key Set Home S Go Home G View All V Previous View P 9 Click the Toggle Isometric button in the View toolbar or choose Isometric in the View menu The drawing window displays an isometric projection as shown in Figure 1 13 Although the isometric projec
76. on and Associativity To complete this exercise you must have one of the following combinations of software installed on your computer e Mechanical Desktop 2 0 and Working Model for Mechanical Desktop e Solid Edge 3 07 and Working Model for Solid Edge SolidWorks 97Plus and Working Model for SolidWorks If you have not installed one of these CAD integration programs please refer to Getting Started with Working Model 3D for installation instructions You can follow the steps in this exercise using any of the supported CAD packages Mechanical Desktop Solid Edge or SolidWorks In most cases the steps are the same for all three CAD packages Where they differ follow the one path for your CAD software e Path A Mechanical Desktop only e Path B Solid Edge only e Path C SolidWorks only 3 1 Exporting a CAD Model A Mechanical Desktop only A1 Launch the Mechanical Desktop program Note that a Motion menu appears in the Mechanical Desktop menubar as shown in Figure 3 1 l Mechanical Desktop is a registered trademark of Autodesk Inc 2 Solid Edge is a registered trademark of Intergraph Corporation 3 SolidWorks is a registered trademark of SolidWorks Corporation Figure 3 1 Motion Menu in Mechanical Desktop Figure 3 2 WM3D Toolbar in Mechanical Desktop 3 1 Exporting a CAD Model 3 3 Simulate Motion Units Working Model for Mechanical Desktop Help About Working Model for Mecha
77. oord 14 Split constraint Don t move anything C Join move con_rod to piston Face to face move con_tod and flip coord 13 Create 4 Select Spherical Joint as the constraint type and click the option labeled Split constraint Don t move anything You can assign the constraint and leave the bodies intact this way You will assemble the joint in a later step Click the Create button in the window A line appears between the two Coords and a split spherical joint icon appears in the Object List as shown in Figure 4 27 At this point the joint is assigned but the bodies are not assembled 4 26 Exercise 4 Creating a Piston Model Figure 4 27 Split Soherical Joint in Object List Frew ohute Pagel Jie Spheucal Sohail Base Cong Split soherical joint 6 Make sure that constraint 15 is selected then click the Join Create Constraint button on the Edit toolbar A dialog appears that offers you the choice of moving the bodies to satisfy the constraints or adjusting the coord location without moving the bodies as shown in Figure 4 28 Figure 428 Join Options Dialog Assemble Moves bodies to satisfy constraints Ci fam ancel Adjusts coord location without moving bodies 7 Click the Assemble radio button then click the OK button Working Model 3D attempts to assemble the bodies using its quick assembly algorithm but in this case the relationship is too c
78. orld Pos Position and Orientation Type the relative position here Indicates attachment to the crankshaft In the field labeled Position amp Orientation with respect to crankshaft enter position at x y z 25 0 5 This specification positions the Coord at the edge of the crankshaft Click the Coord tool on the Sketch toolbar Click anywhere on the connecting rod you will position the Coord precisely in the later steps Double click the Coord The Properties window shows the position of the Coord similar to Figure 4 17 In the field labeled Position amp Orientation with respect to con_rod enter position at x y Z 0 35 0 and orientation as Rx Ry Rz 90 0 0 This specification relative to the body positions the Coord at the right end of the connecting rod This time we are specifying the orientation as well as position because the Coord may have attached to the side surface of the connecting rod and not have the correct orientation Creating a Spherical Joint You will attach the connecting rod to the crankshaft with a spherical joint Figure 4 18 Create Constraint Window 45 Attaching the Connecting Rod to the Crankshaft 4 17 1 Select the Coord on the connecting rod if it is not already selected 2 Holding down the Control key select the Coord located at the perimeter of the crankshaft Both Coords are selected 3 Click the Join Create Constraint button on the
79. osition and Orientation Check this box B Solid Edge only When Working Model 3D imports the piston assembly from Solid Edge it anchors two bodies the connecting rod named CONNECTING ROD PAR 1 and the body named ANCHOR PAR 1 In order for the piston to move properly you must remove the anchor from the connecting rod Only the body named ANCHOR PAR 1 should be anchored to the background B1 Look at the Object List and note any bodies that have an anchor G symbol attached to their icons Two bodies in the linked model ANCHOR PAR 1 and CONNECTING ROD PAR 1 were anchored by Working Model 3D B2 Double click CONNECTING ROD PAR 1 The Properties window for CONNECTING ROD PAR 1 appears B3 If necessary click the Pos tab in the Properties window then click the Anchored box to remove the checkmark as shown in Figure 3 16 3 14 Exercise 3 Exploring CAD Integration and Associativity Figure 3 16 Properties Window Pr osition P age for Connecting Appearance Pos vel Material Geometry CM alel Rod Position and Orientation mm deg x Rao o ooo TO O fo zf2 Rp O World coordinates Body xyz M_A amp nchored Remove this checkmark B4 Click the Toggle Wireframe button in the View toolbar The drawing window changes to a shaded rendering which will make it easier for you to see the motion of the assembly parts as the si
80. ositioned 54 Attaching the Flywheel to the Rotation Axle 5 9 The cylinder is accordingly sized and positioned on the screen see Figure 5 9 En See a ra ra eg r r ee 54 Attaching the Flywheel to the Rotation Axle To assemble the gyroscope top you will use a revolute joint to attach the flywheel to the rotation axle so that the former freely rotates about the latter Coords and Constraints All constraints except for external forces and torques in Working Model 3D consist of a pair of objects called Coords each of which are attached to a body or the background In essence a Coord serves as a medium between a body and the constraint as illustrated in Figure 5 10 5 10 Exercise 5 Modeling a Gyroscope Top Figure 5 10 Concept Construction of a Constraint m In physical terms a Coord is a point element with a coordinate system attached Therefore a Coord has position and orientation as properties For constraints such as spring dampers and separators Coords serve as endpoints to those physical constraints For joints Working Model 3D uses the orientation of the relevant Coords to determine the constraint conditions Chapter 4 Creating a Piston Model provides more discussion on Coords and constraints Attaching a Coord to the Flywheel You will attach Coords to the flywheel and the rotation axle and create a revolute joint based on the two Coords To attach a Coord to the
81. ouse over the crankshaft cylinder Note that the status bar at the bottom of the Working Model 3D window identifies the body with the variable name body n as well as the custom name you have just assigned See Figure 4 9 for an example body 1 crankshaft x Status Bar Identification The custom name for this body also appears in the Object List 4 3 Attaching a Motor to the Crankshaft You will now fix the crankshaft to the background 1 Select the crankshaft if it is not already selected 2 Click the Join Create Constraint button in the Edit toolbar The Create Constraint window appears Figure 4 10 Figure 4 10 Create Constraint Window 4 3 Attaching a Motor to the Crankshaft 4 9 Create Constraint Lx B Rigid Joint from anew coord 7 Revolute Joint Spherical Joint Rigid Joint on Slot Revolute Joint on Slot Spherical Joint on Slot 4 Linear Actuator on crankshaft z to Janew coord z on the background z 3 Constraint Type amp Revolute Motor a Rod Join crankshaft in place at center of crankshaft Rope C Dontmoye anything 4 Separator Join Afe Linear Spring Damper E FETE o Revolute Spring Damper Create 3 Choose Revolute Motor in the list of constraint types The Create Constraint window is best understood when you read the first few lines of the window as a complete sentence In our case the dialog reads Create a motor from a new coor
82. own in Figure 3 21 You can close the Properties window now Properties of constraint 63 Revolute Motor x Appearance Color Constraint Active Motor Motor Type C Orientation Angular Velocity Angular Acceleration C Torque Value deg s coord 15 z axis C SolidWorks only C1 Select ANCHOR 1 in the Object List The Connections List displays a list of the objects connected to this body C2 Double click Conceniric1 the revolute joint that connects ANCHOR 1 to CRANK 1 Figure 3 22 Properties Window Constraint Page for Revolute Motor Figure 3 23 Properties Window Motor Page 3 3 Adding a Motor 3 19 The Properties window for Concentricl appears C3 If necessary click the Constraint tab in the Properties window Then select Revolute Motor for the list of available joint types as shown in Figure 3 22 The revolute joint is changed into a revolute motor Properties of constraint 61 Concentric x Appearance Color Constraint Active Motor Rotate Around os s g gt Noares AI Slide Along CAREVE Z No axes C4 Click the Motor tab in the Properties window Then choose Angular Velocity from the list of Motor Types B Rigid Joint Revolute Joint Spherical Joint Rigid Joint on Slot Revolute Joint on Slot Spherical Joint on Slot gt Linear Actuator amp Revolute Motor Rod
83. posrsns iksn tsrespepsiis sves es 4 16 4 6 Testing Your Mod liser ensena enie ee eN EEEE T E Ei 4 18 Ar Creating the Piston eenia aane a o aE EES SE 4 20 Attaching the Piston to the Background 0 0 0 cee eeeeeneeeecenseceeeeenseeenees 4 21 4 8 Attaching the Connecting Rod to the Piston eect cee cess eeeeeseeeeees 4 22 Creating an Attachment Point on the Connecting Rod 4 22 Creating an Attachment Point on the Piston eee cee eeee cree eee 4 24 Creating a Spherical Joint eee eeeeeeeeeeeeeeeeecesecesecaecaeenaecaeeeae 4 24 4 9 Running the Simulation esene eneore nre ee e r EE Ps Epea Nai 4 29 4 10 Taking Measurements sssessssseeesseeesseeesrsreserrssrerrsrentsrenresensentsseerrnreererenenn 4 30 4 11 Improving the Model antn a e E a E a e E E 4 33 Modeling a Gyroscope Top 51 5 1 Setting Up the Workspaces isccsscssccesiessstaesessstesssusosssachastoasecssseosteveesiadesasssecs 5 2 Changing the Unit System ce ceeeccesecesecnsecseceeecaeeeaeseeeeneees 5 2 Modifying the Edit Grid is sssccssssesscatisgscesescastee ep chsad svtiep Shee susas sa eubaasteteeede 5 3 Changing the Animation Step eee eee ceeeceeeeeeeeeeeeeeeeeeeeeeeeeseensees 5 5 5 2 Creating the Flywheel sa isccs 5 scsessssehsosesstsvasseussacnesscpscedses anes cassscuvcspaseseasseoteeae 5 6 5 3 Creating the Rotation Axle eee ceeeeceeeceeeeeeeeeeeesenseeeeeeeeseeeseeeensees 5 7 5 4 Attaching the Flywheel to the Rotation Axle eee ceeeeeeeeeeeees
84. put slider window 2 8 Exercise 2 Analyzing a Piston Model Figure 2 7 Properties Window Appearanc agefolnpu lider Figure 2 8 Properties Window Inout Page for Input Slider tee Properties of input 37 Motor Rotational Velocity Appearance Input l Name gt Appearance Motor Rotational Velocity Shown n yi Meter al fansucent Graphs Digital Gat 5 Click the Input tab in the Properties window then enter 0 as the minimum value for the input range and 3600 as the maximum value as shown in Figure 2 8 The numbers are interpreted in degrees per second Properties of input 37 Motor Rotational Yelocity x Appearance Input Current value 360 Input Range Minimum 0 Maximum 3 6e 3 Slider steps 100 6 Click the Run button in the Tape Player Control 7 As the simulation runs try dragging the input slider to higher and lower values As you drag the slider to the right the angular velocity of the motor increases and the crank rotates more quickly Conversely as you drag the slider to the left the crank rotates more slowly 8 Click the Stop button then reset the simulation by clicking the Reset button The piston assembly returns to the initial position halfway through the full stroke 2 5 Measuring Reaction Forces 2 9 Click the close box in the input slider window The input slider is still available in
85. raint 40 in the Connections List The Connections List now shows that constraint 40 connects the piston head Pistion_Head_par_1 to the piston pin Piston_Pin_par_l 3 Double click constraint 40 in the Connections list The Properties window displays the properties of constraint 40 as shown in Figure 2 3 Properties of constraint 40 Revolute Joint x Appearance Constraint Color Active m Rigid Joint m Rotate Around Revolute Joint s amp og Spherical Joint C No axes C Al 8 Rigid Joint on Slot Revolute Joint on Slot Slide Along Spherical Joint on Slot cx cy Cz gt Linear Actuator amp Revolute Motor No axes 4 Select a few other objects in the Object list As you select each object it is highlighted in the drawing window and its properties are displayed in the Properties window 2 3 Setting the Initial Condition Working Model 3D allows you to manipulate and configure parts without breaking the assembly constraints that were created when the model was built in Working Model 3D or in the CAD system In this step you will move the piston assembly s configuration so that the simulation starts halfway through the combustion or compression cycle 1 Click the Move tool in the Edit toolbar Figure 2 4 Bounding Box Showing Selected Object 2 3 Setting the Initial Condition 2 5 Move the mouse over the side surface of the crankshaft counte
86. rface of the piston head near the center The z axis of the Coord should point upward Make sure the Coord that you just created is selected then click the Join Create Constraint button in the Edit toolbar The Create Constraint window appears Select Rigid Joint on Slot from the list of available constraint types as shown in Figure 3 30 then click Create A rigid joint on slot appears on top of the piston head This constraint connects the piston head to the background and allows the piston head to move only in the vertical z axis direction 3 4 Adjusting the Joints 3 29 Figure 330 Create Constraint Window B Rigid Joint from ecord 23 z Revolute Joint Spherical Joint 8 Rigid Joint on Slot X Revolute Joint on Slot to anew coord Spherical Joint on Slot B the background Linear Actuator amp Revolute Motor of PISTON HEAD PAR 1 Join PISTON HEAD PAR 1 in place at coord 29 Rod Rope Gort move anything 4b Separator f Join Afe Linear Spring Damper Facetoface o Revolute Spring Damper Lese 6 Choose Go Home in the View menu Your original view of the piston assembly which provides a better view of the motion is restored 7 Click the Run button in Working Model 3D s Tape Player Control The piston head is pushed up and pulled down by the connecting rod as the crank rotates about the crank pin as shown in Figure 3 31 Figure 3 3
87. rweight in the drawing window As you move the mouse over objects in the drawing window a dashed box appears around them to show that they are selected as shown in Figure 2 4 Hold the mouse button down and drag the mouse to rotate the crankshaft As you drag the mouse the crank rotates around the crank pin Position the crankshaft so that the piston is halfway through the full stroke as shown in Figure 2 5 2 6 Exercise 2 Analyzing a Piston Model Figure 2 5 Piston Rotated Halfway through the Full Stroke You can change the configuration by using the Move tool to drag any of the moving parts in the model Try dragging the piston head or the connecting rod NOTE The movement stops when the parts are dragged to the mechanical limits imposed by the physical joints 5 Click the Run button in the Tape Player Control The simulation runs again starting from its new initial position 6 Click the Stop button then reset the simulation by clicking the Reset button The piston assembly returns to the new initial position halfway through the full stroke 2 4 Running a Simulation Interactively You can add input sliders to dynamically change the properties of a constraint as the simulation is running In this step you will add an input slider that controls the angular velocity of the motor that turns the piston s crank 1 Select the revolute motor consiraint 10 in the Object List Figure 2
88. ston Model Figure 4 19 BodiefonnecteavitlSpherical Joint A green cube appears with three axes around the spherical joint when it is selected For constraints that limit any rotational degree of freedom these octagons appear to show the planes on which the rotations are allowed Since a spherical joint allows all three rotational degrees of freedom the joint symbol shows three axes 4 6 Testing Your Mode When you create a simulation model you should check from time to time to make sure that the model s components are in working order If you are creating a complex model and put off testing it until the very end finding a solution may be extremely difficult when your model yields erroneous simulation results So far you have completed the following e Attached a crankshaft to the background with a motor at a skewed angle and e Attached a connecting rod to an edge of the crankshaft with a spherical joint To verify the result you will run the simulation with a specific motor speed You can easily expect that the connecting rod will swing out as the crankshaft rotates gt Figure 4 20 Connecting RodSwungOubythe Crankshatt 46 Testing Your Model 4 19 To start testing simply run the simulation 1 Click the Run button in the Tape Player Control The simulation starts while the frame indicator shows you the number of frames calculated Note how the connecting rod swings out as the crankshaft rotates as s
89. t important for this exercise 5 Double click the force icon in the drawing window or in the Object List The force s properties appear in the Properties window 6 If necessary click the Force tab then enter 10 in the z field to apply a 10 Newton force downward as shown in Figure 2 17 The force s Coord attachment dictates this orientation setting Properties of constraint 46 Force x Appearance Color Active Force I Follows body Ff N yf ON rfid oN Piston_Head_par_1 coordinates 2 7 Fine tuning the Simulation 2 17 Choose Go Home in the View menu Your original view of the piston assembly which provides a better view of the motion is restored Click the Run button in the Tape Player Control As the simulation runs the piston behaves like a pendulum because the pressure is applied constantly which isn t a realistic scenario Click the Stop button then reset the simulation by clicking the Reset button The piston assembly returns to the initial position Modify the Force to Simulate Realistic Throttle As a final step you will modify the force to simulate realistic throttle by using a formula to control when the force is applied 1 Double click the force icon in the drawing window or in the Object List The force s properties appear in the Properties window Click the Active tab Click the Active when the following formula is greater than 0 radio button
90. tance3 on Crank 1 and Distance3 on CONNECTING ROD 1 should be selected when you are done C4 Press the Delete key The rigid joint and the two Coords are removed from the model Adjust the Joints on the Crank Pin The crank pin has been given the right number of constraints by Working Model 3D but the joints have been given too much freedom In this step you will change one revolute joint on slot which can slide along an axis 3 26 Figure 3 27 Properties Window Constraint Page for Revolute Joint Exercise 3 Exploring CAD Integration and Associativity into a standard revolute joint which cannot slide to eliminate a degree of freedom This change models the true motion allowed between the crank pin and other assembly parts C1 Select CRANK PIN 1 in the Object List C2 C3 Properties of constraint 67 Concentric3 x Appearance Color Constraint Active The Connections list displays the constraints and Coords attached to the crank pin Double click Concentric3 the revolute joint on slot in the Connections List The Properties window for Concentric3 appears If necessary click the Constraint tab in the Properties window Then select Revolute Joint for the list of available joint types as shown in Figure 3 27 The revolute joint on slot is changed into a revolute joint An alternative way to change a revolute joint on slot into a standard revolute joint is
91. the Object List 2 6 Visualizing Dynamics with Vectors Working Model 3D allows you to visualize vectors in 3D space as the simulation runs Although the animated simulation itself serves as a powerful visualization tool hard to see qualitative data such as vectors reveal even more information that can t be seen in a physical prototype Display the Acceleration of the Connecting Rod In this step you will display vectors that show the acceleration of the connecting rod 1 Double click Connecting_Rod_par_1 in the Object List The connecting rod s properties appear in the Properties window 2 Click the right arrow in the Properties window to scroll the tabs until the Vectors tab is displayed then click the Vectors tab The Vectors page is displayed as shown in Figure 2 11 2 12 Exercise 2 Analyzing a Piston Model Figure 2 11 Properties Window VectorPagefothfonnecting Rod Properties of body 4 Connecting_Rod_par_1 x Material Geometry CM Central Inertia Vectors Color 4 Show I Velocity Vector T Rot Velocity Vector T Rot Acceleration Vector I Force Vector I Torque Vector 3 Click the Acceleration Vector box to put a checkmark in it 4 Click the Toggle Wireframe button in the View toolbar The drawing window changes to a wireframe rendering which will make it easier for you to see the acceleration vector which is often hidden by the sides of the crank as the simulation r
92. the Object List but it is temporarily hidden from view You can redisplay the input slider by double clicking it in the Object List 2 5 Measuring Reaction Forces You can add meters to the model to measure the reaction forces in the piston assembly For example in this step you will create a meter to measure the constraint force experienced by the revolute joint between the connecting rod and the piston pin 1 Select Piston_Pin_par_1 in the Object List The list of constraints and Coords connected to the piston pin appears in the Connections list Select constraint 34 the revolute joint that connects the connecting rod to the piston pin in the Connections List Note that coord 32 is listed as one of the Coords attached to constraint 34 in the Connections list Choose Force on Connecting _Rod_par_1 expressed in coord 32 in the Measure menu A new meter window opens titled constraint 34 force on coord 32 as shown in Figure 2 9 The new meter will display the x y and z components and the total constraint force exerted by constraint 34 on coord 32 as separate plots by default 2 10 Exercise 2 Analyzing a Piston Model e Working Model 3D Piston Loli Figure 2 9 File Edit View World Object Grid Measure Tools Window Help Constraint Force Meter Window Dealkse aAA ene ele 3 ea Piston Ea amp constraint 34 force on coo Bifa E3 Name Type Fx Fy Fz
93. the Vel tab in the Properties window The Properties window shows the initial velocity and angular velocity of the flywheel 2 To specify the angular velocity about the z axis of the flywheel enter Wz 14400 as shown in Figure 5 22 The angular velocity of a body is specified in terms of the body s coordinate axes Since the flywheel is to spin about its z axis you are specifying the angular velocity in the z axis In this case the angular velocity of 14400 degrees per second corresponds to 2400 rpm Figure 5 22 Assigning Initial Angular Velocity 5 7 Running the Simulation 5 23 Properties of body 1 Cylinder x Appearance Color Pos Vel Material Geometry alel Velocity and Angular Velocity Ve fo We fo Vy fo Wy fo Type 14400 and press Enter The number format is automatically converted to 1 44e 4 5 7 Running the Simulation To better observe the precession in which the axle slowly rotates about the global z axis you will prepare another view angle of the model 1 Click once in the blank area of the right window 2 Press T on the keyboard The window provides the top view of the model as shown in Figure 5 23 The keyboard shortcut T stands for top view 5 24 Exercise 5 Modeling a Gyroscope Top Figure 5 23 Getting the Top View FE e Working Model 3D Untitled1 _ Oy x File Edit View World Object Grid Measure Tools Window Help olaja
94. then enter the following formula as shown in Figure 2 18 and body 7 v z lt 0 body 2 wl lt 62 The formula applies the explosive force only when the piston is coming down and cuts off the push to limit the motor to approximately 600 rpm 62 rad sec NOTE All formula expressions are interpreted in SI unit system so you must enter 62 rad sec the SI equivalent of 600 rpm 2 18 Exercise 2 Analyzing a Piston Model Figure 2 18 P roperties Window Appearance Color Active Force l Active Page for Force C Always active Active when the following formula is greater than 0 and body 7 v 2 lt 0 Ibody 2 wl lt 62 4 Run the simulation The piston behaves as expected under the realistic throttle force Verify the Result You can verify that your model is accurate by creating a meter to measure angular velocity of the crankshaft and setting the angular velocity unit system to RPM The angular velocity of the crankshaft should settle at around 600 rpm 1 Select Crank_par_1 the left half of the crank in the Object List 2 Choose Angular Velocity from the Measure menu A new meter window appears titled Angular Velocity of Crank_par_1 3 Choose Numbers amp Units in the World menu The Numbers amp Units dialog appears as shown in Figure 2 19 2 7 Fine tuning the Simulation 2 19 Figure 2 19 Numbers amp Units Dialog aionomies Numbers l C Fixed
95. this step you will change two revolute joint on slots which can slide along an 3 22 Exercise 3 Exploring CAD Integration and Associativity Figure 3 25 Properties Window Constraint Page for Revolute Joint axis into standard revolute joints which cannot slide to eliminate a degree of freedom This change models the true motion allowed between the crank pin and other assembly parts A1 Select CRANKPIN_1 COMP1_1 in the Object List The Connections list displays the constraints and Coords attached to the crank pin A2 Double click constraint 71 the first revolute joint on slot in the Connections List The Properties window for constraint 71 appears A3 If necessary click the Constraint tab in the Properties window Then select Revolute Joint for the list of available joint types as shown in Figure 3 26 The revolute joint on slot is changed into a revolute joint An alternative way to change a revolute joint on slot into a standard revolute joint is to choose No axes from the Slide Along section of the Constraint page Properties of constraint 65 Revolute Joint x Appearance Color Constraint Active r Rotate Around amp g Rigid Joint Revolute Joint Spherical Joint Rigid Joint on Slot Revolute Joint on Slot Spherical Joint on Slot m Linear Actuator amp Revolute Motor Roe No axes All r S
96. tion appears to have less depth cues than the perspective projection you can verify alignments of bodies and components especially using one of the head on views Figure 1 13 Isometric Projection 1 8 Analyzing the Simulation 1 15 10 Choose Perspective in the View menu Your view changes back to a 3D perspective 11 Click the Run button in the Tape Player Control and then use the view manipulation tools while the simulation is running You can change your view zoom in on objects rotate around the world and so forth while the simulation is running 12 Click the Reset button after running for a few dozen frames 1 8 Analyzing the Simulation This section introduces you to a few of the many analysis tools available in Working Model 3D You can gain insights into the motion being simulated and the forces at work by displaying vectors while the simulation is running adding meters that measure values you want to track Displaying a Velocity Vector on the Coin In this step you will display a vector that will show the velocity of the coin as the simulation runs Figure 1 14 PropertiesVindowwector age forthe Coin Exercise 1 Simulating a Dropping Coin Double click the coin in the document window or in the Object List that runs along the left edge of the window The Properties window appears Click the right arrow in the Properties window to scroll the tabs until the Vectors tab is visible Then click th
97. to choose No axes from the Slide Along section of the Constraint page m Rigid Joint Rotate Around Revolute Joint C S E Spherical Joint No axes All Slide Along E Ss Rigid Joint on Slot Revolute Joint on Slot Spherical Joint on Slat m Linear Actuator amp Revolute Motor No axes El GP All CAD Packages 1 Click the Run button in Working Model 3D s Tape Player Control 3 4 Adjusting the Joints 3 27 The crank is driven around the crank pin by the motor and the connecting rod swings freely as shown in Figure 3 28 Figure 3 28 Connecting Rod Swinging Freely 2 Click the Stop button The only remaining problem is that the piston head flops around because its motion is not adequately constrained Constrain the Motion of the Piston Head In this step you will add a new constraint that limits the motion of the piston head so that it can only move vertically El GY All CAD Packages 1 Reset the simulation by clicking the Reset button The piston assembly returns to its starting position the keyboard so that you can see the top of the piston head 2 Click the Rotate Around tool in the View toolbar or press T on Your view should be similar to Figure 3 29 3 28 Figure 3 29 Top of the Piston Head Exercise 3 Exploring CAD Integration and Associativity Click the Coord tool in the Sketch toolbar then place a Coord on the top su
98. ton assembly is displayed in the document window as shown in Figure 2 1 a Working Model 3D Piston oy x Figure 2 1 File Edit View World Object Grid Measure Tools Window Help laj x Model ofa Piston Assembly Disa ole 1 esee elll eae 9 alalalaie T Polymesh Connecting_Ro Polymesh Crank_par_1 Polymesh Crank_par_2 Polymesh Crank_Pin_par_1 Polymesh Piston _Head_pa Polymesh amp Piston_Pin_par_1 Polymesh constraint 16 Revolute constraint 22 Revolute constano Revolute p G Connections TE E MIMI For Help press F1 Frame 0 Time 0 s 7 gt 2 Click the Run button in the Tape Player Conirol This base model shows the piston mechanism in motion driven by the motor attached to the crankshaft Since this is the first time the simulation is being run Working Model 3D calculates the dynamics and stores the data 3 Repeat the simulation by clicking the Stop button then the ma Reset button and then the Run button again The animation is faster this time because the history has already been calculated Figure 2 2 Object List and Connections List 2 2 Understanding Part Relationships 2 3 2 2 Understanding Part Relationships You can see how the parts of the model are connected by selecting them in the Object Manager that appears along the left edge of the document window as shown in Figur
99. traint 79 the other rigid joint and coord 59 and coord 61 from the connecting rod 3 24 Figure 3 26 Properties Window Constraint Page for Revolute Joint Exercise 3 Exploring CAD Integration and Associativity Adjust the Joints on the Crank Pin The crank pin has been given the right number of constraints by Working Model 3D but the joints have been given too much freedom In this step you will change two revolute joint on slots which can slide along an axis into standard revolute joints which cannot slide to eliminate a degree of freedom This change models the true motion allowed between the crank pin and other assembly parts B1 Select CRANK PIN PAR 1 in the Object List The Connections list displays the constraints and Coords attached to the crank pin B2 Double click constraint 69 the first revolute joint on slot in the Connections List The Properties window for constraint 69 appears B3 If necessary click the Constraint tab in the Properties window Then select Revolute Joint for the list of available joint types as shown in Figure 3 26 The revolute joint on slot is changed into a revolute joint An alternative way to change a revolute joint on slot into a standard revolute joint is to choose No axes from the Slide Along section of the Constraint page Properties of constraint 69 Revolute Joint x Appearance Color Constraint Active
100. uns 5 Click the Run button in the Tape Player Control As the simulation runs the acceleration vector is displayed but it is difficult to see because it is small In the next step you will resize the acceleration vector to make it easier to see 6 Click the Stop button then reset the simulation by clicking the Reset button The piston assembly returns to the initial position Make the Acceleration Vector More Visible You can change the size and color of the vectors displayed to make them more visible as the simulation runs 1 Choose Vector Display in the View menu The Vector Settings dialog appears as shown in Figure 2 12 Figure 2 12 Vector Settings Dialog Figure 2 13 Color Dialog Vector Settings x Lox ca 2 6 Visualizing Dynamics with Vectors 2 13 Length Velocity 0 05 s Color Acceleration 0 03 2 Color Force 0 03 kgs 2 Color Rot Velocity 0 mms Color Rot Acceleration f mms 2 Color Torque 5e 6 s 2 kg mm Color Cancel 2 Enter 0 09 as the scaling factor for the length of the Acceleration vector The default value is 0 03 Because you are tripling the scaling factor the acceleration vectors will now be three times as long 3 Click the Color button next to the Acceleration vector in the Vector Settings dialog The Color dialog appears as shown in Figure 2 13 Color 21x Basic colors z ima me Hl Sees ee ed EE ET SEE eee ER E
101. ut the selected objects 1 6 Exercise 1 Simulating a Dropping Coin Figure 1 5 Properties Window Figure 1 6 Rotated Coin Properties of body 1 Cylinder x Appearance Pos vel Material Geomety CM gt Position and Orientation m deg x 103 Rx 120 a Type 20 here Rx Rotation World coordinates n Type 0 3 here Z position 2 Change the z position of the coin by typing 0 3 into the Z edit box then press Enter Notice that the coin moves upwards immediately The body position is represented as the position of the coordinate origin of the cylinder in the global coordinates The coordinate origin of the cylinder coincides with the geometric center of the cylinder 3 Change the orientation of the coin by typing 20 into the Rx edit box Press Enter The coin rotates by 20 degrees see Figure 1 6 about the body s x axis Working Model 3D expresses the orientation of the body in the local coordinate system using body XYZ angles Exercise 5 Modeling a Gyroscope Top discusses the body XYZ angle representation in more detail For now it suffices to say that the body orientation is expressed in terms of a series of rotations about its axes 1 3 Positioning the Coin 1 7 4 Close the Properties window 5 Click the blank area of the screen The thick edges disappear see Figure 1 7 Figure 1 7 Selection Handles Bounding Box When you select a body the edges
102. w World Object Grid Measure Tools Window Help rag states id Disa Hele o o1slelele ele fr elslolsio 2 21 IIe kalta body 1 amp body 2 constraint 5 constraint 5 eb coord 3 coord 4 coord 6 Connections to body 1 body 1 constraint 5 amp body 1 constraint 5 coord 3 6 Click the Coord tool on the Sketch toolbar 7 Click at the bottom end of the rotation axle Note that the left window also shows the Coord is attached 8 Inthe Properties window verify that the position and orientation of the Coord are X Y Z 0 0 2 0 and Rx Ry Rz 0 180 0 Creating a Spherical Joint You will connect the last two Coords with a spherical joint 1 In either window select coord 7 the Coord attached to the bottom end of the rotation axle Note that the Coord appears selected on both right and left windows 2 In either window hold the Control key down and select coord 6 the Coord attached to the background at the global origin Note that the two Coords are selected in both windows Figure 5 20 Gyroscope Attached to the Ground 5 5 Attaching the Gyroscope tothe Ground 5 21 3 Click the Join Create Constraint button on the Edit toolbar The Create Constraint window appears 4 Select Spherical Joint as the constraint type 5 Choose the option labeled Join move body 2 to coord 6 The option indicates that body 2
103. w coord z on the background x amp Revolute Motor Rod Join piston in place at center of piston vw Rope Dortmove anything 4 Separator Eia Afe Linear Spring Damper e EEE o Revolute Spring Damper Create Since you selected a single body without Coords Working Model 3D automatically presents the only reasonable option The option means that Working Model 3D will create two Coords one attached to the piston the other attached to the background and create a rigid joint on slot to connect the body to the background One of the Coords will be attached to the body at its frame origin coordinate origin 4 Click the Create button in the window 4 22 Exercise 4 Creating a Piston Model Figure 4 23 Rigid Joint on Slot Created A rigid joint on slot icon appears at the center of the piston see Figure 4 23 You may want to zoom in with the zoom tool to obtain a better view Pian N waiti The small green line segment indicates the translation axis a e Note that the small green line segment indicates that this slot joint allows single degree of freedom in translation Therefore as it stands the piston is allowed to slide up and down like we would like it to 4 AttachinghConnectinRoddhPiston You will attach the connecting rod to the piston with a spherical joint just as you attached the connecting rod to the crankshaft CreatingiAttachmenPoindnhEConnect
104. window 1 On the Motor page of the Properties window select Angular Velocity and type 40 in the value field as shown in Figure 4 14 The specification calls for a velocity controlled motor maintained to rotate at 40 degrees per second When you run the simulation Working Model 3D will provide as much torque as necessary in either direction to maintain the specified angular velocity 2 Click the Run button in the Tape Player Control Note that the crankshaft rotates counterclockwise if seen from the positive z Also note that the frame indicator at the bottom shows the current frame being calculated 3 After several frames click the Reset button Figure 4 15 Specifying Motor Properties with Formula Language 4 3 Attaching a Motor to the Crankshaft 4 13 Before proceeding to construct the rest of the model we will modify the motor function so that it only generates some torque at the beginning of the motion just like a starter motor would 4 Double click the motor icon The Properties window shows the motor characteristics 5 Select Torque as Motor Type and type the following expression in the Value field as shown in Figure 4 15 if time lt 0 3 0 005 0 Properties of constraint 4 Revolute Motor x Appearance Constraint Color Motor Active Select Torque as the r Motor Type p ENEA motor specification C Angular Velocity C Angular Acceleration Type the expression here
105. xercise 4 Creating a Piston Model Figure 4 29 Joining Process E a Working Model 3D Untitled3 _ 5 x File Edit View World Object Grid Measure Tools Window Help l x Djela siele o slolelcy se T eela ele olAl alalslels A con_rod Box amp crankshaft Cylinder piston Cylinder 2 constraint 4 Revolute constraint 1 2 Rigid Joint constraint 8 Spherical constraint 15 Spherical Assembling constraint 15 constraint 8 error 0 122 mm e constraint 4 error K For Help press F1 After a while the progress bar reaches the completion and the progress dialog disappears At this point the model is fully assembled as shown in Figure 4 30 and you are ready to run the simulation Moving the Coords to Join Closer Together Another approach to dealing with assembly errors is to use the Move tool to position the Coords that you want to join closer together Follow these steps if you prefer to resolve the assembly problem using this method 1 Click the Cancel button to close the Assembly Error dialog 2 Select the Move tool on the Edit toolbar 3 Drag the connecting rod and reposition it so that the Coord on its end is near the Coord on the piston 4 Make sure that constraint 15 is selected then click the Join Create Constraint button on the Edit toolbar 5 Click the Assemble radio button then click OK Working Mod
106. y moves to the global origin 5 5 Attaching the Gyroscope tothe Ground 5 19 Creating an Attachment Point on the Gyroscope To attach another Coord at the bottom of the rotation axle you will need to look at the bottom 1 Choose New Window in the Window menu The second window appears presenting the view of the gyroscope model from the same view angle Working Model 3D allows you to open multiple windows for a single document As shown below individual windows can have completely independent view angles yet any changes to the model are updated in all windows simultaneously 2 Choose Tile in the Window menu The two windows are repositioned and appear side by side You can resize the Object Manager pane of either or both windows to make more room available for the drawing pane by dragging the vertical lines that separate the panes 3 Click the Rotate Around tool on the View toolbar The mouse pointer changes its shape accordingly Alternatively you can select the Rotate Around tool by pressing F4 on the keyboard 4 On the right window click anywhere on the rotation axle and hold the mouse button Note that the view in the left window remains unchanged 5 Drag the mouse so that the bottom end of the rotation axle is facing you See Figure 5 19 as an example 5 20 Exercise 5 Modeling a Gyroscope Top Figure 5 19 e Working Model 3D Untitled Elx Multi lo Windows Placed Side bi A Fie Edit Vie
107. z returns the angular velocity in radians per second SI units so other values in the formula must also be expressed in radians per second for consistency The constant 6 283 radians per second is equivalent to 360 degrees per second BEM 4 11 Improving the Model 4 35 The expression implements a rudimentary proportional control system which monitors the angular velocity of the crankshaft represented as body 1 in the formula Note that according to this expression the motor is capable of applying torque in either direction 4 Click the Run bution in the Tape Player Control Note that the force curve on the spherical joint is much smoother 5 Run the simulation until several rotation cycles are completed and click the Reset button in the Tape Player Control You can export the meter data to a text file for further analysis by another application program For more information please see the Working Model 3D User s Manual 4 36 Exercise 4 Creating a Piston Model 5 1 EXERCISE 5 Modeling a Gyroscope Top The goals of this exercise are to show you how to create simple constrained bodies in Working Model 3D You will create a model of a simple gyroscope top consisting of a flywheel and a rotation axle fixed to the background with a spherical joint thus having three rotational degrees of freedom You will give the gyroscope an initial angular velocity to exhibit precession which cannot be demonstrated with a

Working Model 3D

Contents

Download Pdf Manuals

Related Search

Related Contents