Home

TUTORIAL

1. RBS coos sn Rote Roy ES Zoom 23 4 Dolly NUM Figure 5 15 HVE Event Editor executing the EDVSM L R Tire Blowout simulation Now we re ready to execute the event gt Using the Event Controller click Play to execute the event to simulate the loss of pressure at the right rear tire Allow the event to rununtil the simulation terminates at t 5 00 seconds The EDVSM event is shown in Figure 5 14 I amp S NOTE While the event is executing watch the current results in the Key Results windows To study the effect of a blow out at the left rear tire perform the following steps gt Click on Add Event The Event Information dialog is displayed gt Select Ford Bronco II Loaded fromthe Active Vehicles list 2 Select EDVSM from the Calculation Method options list 2 Enter a name for the event L R Tire Blow out 2 Press OK to display the event editor Creating the Events Tutorial Repeat the steps used in the previous event to set up our left rear tire blow out simulation gt Choose Set up from the menu bar and select Position Velocity gt Directly enter the vehicle s initial position X 12 3 ft Y 0 ft Its initial heading angle is 0 degrees and need not be modified gt Click the Velocity Is Assigned checkbox Enter the initial velocity 50 mph To enter the steer angles perform the following steps 2 Click on the Set up Menu select Driver Controls The Steering Table dialog is displayed gt Enter
2. Rp NOTE Rememberto press Apply or Enter after entering a value otherwise the value is not assigned The vehicle initial conditions are now established Let s enter the driver controls The steering inputs were obtained from the validation study reference 4 However the throttle brake and gear selection were not documented in the study and were determined by repeated adjustments until the correct vehicle acceleration was achieved EDVSM Creating the Events Steering Input To enter the steer angles perform the following steps gt Click on the Set up Menu select Driver Controls The Driver Controls dialog is displayed with an empth steer table gt Click on the Table option list and choose the At Axle option gt Enter the steer angles for the front wheels as shown below Table 5 1 Steer Table entries for the Ford Bronco Steer Angle at Axle degrees Right Front Left Front 0 00 0 00 0 00 7 42 0 20 0 20 7 97 1 19 1 19 8 63 3 50 3 50 10 21 4 00 4 00 12 00 4 00 4 00 The steering table is now ready for our event Creating the Events Tutorial Throttle Input To enter the throttle table perform the following steps gt Click on the Driver Controls dialog s Throttle tab The Throttle Table is displayed gt Click on the Table option list and choose the Wide open Throttle option 2 Enter the throttle position as shown below Table 5 2 Throttle Table entries
3. 2 Place the mouse cursor in the Filename text field and enter EdvsmTutorial gt Click SAVE The current case data are saved in the hve supportFiles case subdirectory Rp NOTE Saving the file occasionally is a highly recommended practice EDVSM Creating the Events Creating the Events As mentioned at the outset of the tutorial our EDVSM tutorial includes several events The first event is a curb tripped rollover prepared as part of the EDVSM validation project The next four events simply use the first event and introduce a blow out at each of the four tires Rollover Validation Event To create the rollover event perform the following steps 2 Choose Event Mode The Event Editor is displayed gt Click on Add New Object The Event Information dialog is displayed gt Select Ford Bronco II Loaded fromthe Active Vehicles list gt Select EDVSM from the Calculation Method options list gt Enter a name for the event Curb tripped Rollover 33 NOTE HVE will append the name of the calculation method to the event name thus the complete event name will become EDVSM Curb tripped Rollover 2 Press OK to display the event editor Now we re ready to set up the first event 2 Using the Event Editor dialog select Ford Bronco II Loaded from the Event Humans amp Vehicles list then choose Set up from the menu bar and select Position Velocity The Ford Bronco is displayed at the earth fixed origin gt If
4. 29 91 Gravity Constant in sec 2 386 40 3 D ENVIRONMENT TERRAIN DATA 3 D Geometry Filename Unknown Number of Polygons 806 GetSurfaceInfo From Previous Polygon Minimum Terrain Elevation ft 0 03 Maximum Terrain Elevation ft 0 30 ET Figure 5 19 Environment Data report for EDVSM Curb tripped Rollover To view the Environment Data report for the EDVSM Curb tripped Rollover I event perform the following steps lt gt Click Add New Object The Report Window Information O dialog is displayed E gt Select EDVSM Curb tripped Rollover from the Active Events list gt Click on the Selected Output option list and choose Environment Data Press OK The Environment Data report is displayed for the EDVSM Curb tripped Rollover event as shown in Figure 5 19 EDVSM Viewing Results Vehicle Data The Vehicle Data report for EDVSM contains all the vehicle data groups Sprung Mass Suspension Tire Brake and Driver Controls 4 Vehicle Data EDVSM Curb tripped Rollover x r VEHICLE DATA General Vehicle Information Vehicle Name Ford Bronco II Loaded Overall Length in 158 50 verall Width in 65 00 CG to Front End in 74 00 CG to Rear End in 84 50 Wheelbase in 94 00 Front Track Width in 56 50 Rear Track Width in 56 60 Front Overhang in 28 40 Rear Overhang in 36 10 CG to Front Axle in 45 60 CG to Rear Axle in 48 40 CG Height Above Ground in 28 70 Total
5. This is of course important because the sun is the primary light source for the scene gt Edit the default environment name enter Jefferson City Airport 2 To add the environment geometry file to our case click on Open The Environment Geometry File Selection dialog is displayed gt Click onthe Files of Type option list and choose h3d Files A list of environment geometry files using the HVE file format is displayed in a list box Double click on EDVSMValidAASHTOCurb h3d to choose the environment file and remove the dialog gt Press OK The selected environment 1s added to our case and displayed in the Environment Viewer see Figure 5 7 Use the viewer thumb wheels to view the scene Saving the Case Now that we ve created all the objects vehicle and environment for our case let s save the case file Creating the Environment Tutorial Xx ae lgre asosTt 4 OK lt s gt gt 0 0000 0 0000 Rote Roty Ey Zoom 248 Doly NGM Figure 5 7 3 D Environment used for our EDVSM tutorial gt Click on the File menu and choose Save The Save as File Selection dialog is displayed i lt ra e He Rp NOTE The Save as dialog is displayed because the case has not been saved previously so we need to enter a filename 2 In the Case Title text field replace Untitled with EDVSM Tutorial Case Rp NOTE The Case Title is displayed as a heading on all printed output reports
6. To document the resulting path as well as some other pertinent results let s select the CG path coordinates velocity and accelerationfromthe Variable Selection dialog gt Click on Select Variables in the Ford Bronco IL Loaded Variable Output window The Variable Selection dialog for Ford Bronco II Loaded is displayed as shown in Figure 5 22 Viewing Results Tutorial Variable Selection EDVSM Curb tripped R E3 Object Name Ford Bronco Il Loaded Current Variable Kinematics Dutput Groups Variables Kinetics Accelerometers Accel 1 Accelerometers Accel 2 Accelerometers Accel 3 Accelerometers Accel 4 Accelerometers Accel 5 Damage Tires Axle 1Right Quter Tires Axle 1 Right Inner Sideslip Tires Axle 1 Left Outer u vel Tires Axle 1 Left Inner v vel Clear Selection Cancel Figure 5 22 Variable Selection dialog used for selecting results displayed in the Variable Output table l lt a fe He The Kinematics Output group is the default selection and the Kinematics variable list is displayed Let s add X Y Yaw and Path Radius to the Key Results window gt Select X Y Z Roll Pitch Yaw V tot Sideslip u vel v vel w vel Roll Vel Pitch Vel Yaw Vel Acc tot Fwd Acc Lat Acc Vert Acc p dot q dot and r dot from the list 33 NOTE Feel free to add additional variables to the Variable Output window You might be especially interested in the
7. Weight 1b 4329 20 Effective Air Drag in 2 0 000076 Aerodynamic Drag Cd 0 4500 Frontal Area in 2 2999 90 Body Data Number of Body Nodes 2606 Number of Damaged Nodes 0 Node Stiffness lb in Front 167 20 Right 110 60 Back 539 30 Left 110 60 Top 100 00 Bottom 100 00 Node Friction 0 500 Figure 5 20 Vehicle Data report for EDVSM Curb tripped Rollover To view the Vehicle Data report for the EDVSM Curb tripped Rollover event perform the following steps 2 Click Add New Object The Report Window Information dialog is displayed gt Select EDVSM Curb tripped Rollover fromthe Active Events list gt Click onthe Selected Output option list and choose Vehicle Data gt Press OK A portion of the Vehicle Data report is displayed for EDVSM Curb tripped Rollover is shown in Figure 5 20 33 NOTE The EDVSM Vehicle Data report is too large to fit in the viewer Use the scroll bars to view the entire report Viewing Results Tutorial Program Data The Program Data report includes the simulation control parameters and other run time information 4 Program Data EDVSM Curb tripped Rollover x SIMULATION CONTROLS Integration Method Fixed Runge Kutta Max Simulation Time sec 15 0000 Normal Integration dt sec 0 0025 utput Interval sec 0 1000 Linear Term Vel mph 2 00 Angular Term Vel deg sec 5 00 General Information EDVSM Version Number 2 50 Wheel Spin Int Const 0 00 Ter
8. for the Ford Bronco Throttle Position Percent WOT 0 00 0 78 5 30 0 78 7 50 0 60 10 30 0 57 10 40 0 00 The throttle table is now ready for our event l x a fe He EDVSM Creating the Events Gear Selection Input To enter the steer angles perform the following steps gt Click on the Driver Controls dialog s Gear tab The Gear Selection Table is displayed gt Click on the Number of Shifts option list and choose Shift gt Enter the time and gear selection as shown below Table 5 3 Gear Selection table entries for the Ford Bronco Gear Selection 0 00 Shift Into 2nd 33 NOTE The gear selection and throttle tables were created by trial and error as required to match the experimental and simulated velocity profiles Brake Input To enter the brake input perform the following steps gt Click on the Driver Controls dialog s Brakes tab The Brake Table is displayed gt Click on the Table Is option list and choose Pedal Force gt Enter the brake pedal force as shown below Table 5 4 Brake Table entries for the Ford Bronco Brake Pedal Force Ib 10 30 0 00 10 40 10 75 2 Press OK to accept the driver control tables The driver control inputs are now complete 5 16 Creating the Events Tutorial Simulation Controls This event lasts more than 5 seconds To prevent premature termination
9. information Variable Output A table containing user selectable time dependent simulation results Trajectory Simulation A 3 D visualization of the event displayed at a user selectable time interval Damage Profiles A 3 D visualization of the vehicle damage displayed at a user selectable time interval To view the output reports we need to be in Playback mode 2 Choose Playback Mode The Playback Editor is displayed l x a fe He 33 NOTE Our tutorial uses the Curb tripped Rollover event to illustrate the procedures for viewing output reports You can use the same procedures for viewing reports for any of the events in the case EDVSM Viewing Results Report Windows The reports listed on the previous page are displayed by selecting Preview Windows Each Report Window contains an individual report EDVSM R F Tire Blow out EDVSM L F Tire Blow out EDVSM R R Tire Blow out EDVSM L R Tire Blow out Window Name E DYSM Curb tipped Rollover Select Output Accident History m Cancel Figure 5 16 Report Window Information dialog showing the name of each event in the current case To view the reports produced by the EDVSM Curb tripped Rollover event perform the following steps 2 Click Add New Object The Report Window Information dialog is displayed as shownin Figure 5 16 and includes a list of the active events EDVSM Curb tripped Rollover is the event whose output we ll
10. let s increase the default maximum simulation time 2 Click on the Options menu and choose Simulation Controls The Simulation Controls dialog 1s displayed gt Edit the Maximum Simulation Time changing it from 5 to 15 seconds 2 Press OK to update the simulation controls Key Results Let s look at some Key Results during execution gt Ifthe Key Results window is not displayed choose Show Key Results from the Options menu 2 Drag the Key Results window to a convenient location where it does not block the view but still allows access to the viewer thumb wheel controls in case we want to change the view gt Click on Select Variables in the Ford Bronco II Loaded Key Results window The Variable Selection dialog for Ford Bronco II Loaded is displayed The vehicle kinematics are already selected Let s add Tire Fx Fy Fz and Steer Angle to the Key Results window gt Click Tires Axle 1 Right Outer from the variable group list The Variable Selection list for the right front tire is displayed see Figure 5 9 l x a fe EB 2 33 NOTE For calculation methods that support dual tired vehicles you can select the Inner or Outer tire however EDVSM does not support dual tires gt Select Fx Fy and Fz tire forces from the list 2 Repeat the above steps by choosing the tire forces for the left front right rear and left rear tires Now let s add the wheel steer angles
11. observe the effect on vehicle behavior forthe various blown tire locations The blow out model is extremely powerful For additional information about vehicle response to tire blow out see reference 7 One final but very important point This tutorial involves a Ford Bronco II This particular vehicle was selected because it was included in a rigorous validation study involving vehicle rollover 6 In this study the vehicle was subjected to extremely violent experimental conditions i e curb tripped impact in an effort to induce a rollover response The Ford Bronco II s response to these conditions as well as to the tire blow out simulations included in this tutorial is substantially the same as the response of other multi purpose vehicles Viewing Results Tutorial Viewing Results Now that we have produced our EDVSM simulations let s take a detailed look at the results The Playback Editor is used for reviewing and printing reports for each event in the current case as well as for producing video output EDVSM produces the following reports Messages A list of messages produced by the current run Accident History A table of initial and final positions and velocities Environment Data A list of the visual and physical environment parameters used by EDVSM Vehicle Data A series of tables containing the vehicle data used by EDVSM including tire blow out information Program Data A table containing program control
12. the left side tires As a result the left side outside tires are more heavily loaded and produce a greater portion of the cornering force It follows then that a blow out in the left side tires should have a greater effect on vehicle handling and controllability This fact is confirmed by the simulation results Note also the difference in vehicle cornering response for blow outs at the front tires compared to the rear tires Front tire blow outs cause the vehicle to tend to maintain a straight ahead path or p ow This is generally referred to as an understeer characteristic For rear tire blow outs the vehicle tends to become unstable and spin out This is generally referred to as an oversteer characteristic Oversteeris generally considered an undesirable characteristic although a small tendency for oversteer is often designed into high performance vehicles Spend a few minutes reviewing each event noting how the location of the blown tire affects response You ll find this procedure useful the next time you need to reconstruct an accident involving a tire blow out It is quite instructive to look carefully at all tire forces Fx Fy Fz before during and after the blow out to learn exactly how a blown tire affects vehicle behavior 33 NOTE Look carefully you ll see a lot of interesting phenomena taking place You might also find it interesting to change the amount and timing of the steering and introduce braking to
13. the vehicle s initial position X 123 ft Y 0 ft Its initial heading angle is 0 degrees and need not be modified gt Click the Velocity Is Assigned checkbox Enter the initial velocity 50 mph The vehicle initial conditions are now established Let s enter the driver controls Only steering inputs need to be supplied To enter the steer angles perform the following steps 2 Choose Set up from the menu bar and select Driver Controls The Driver Controls dialog is displayed with the default steer table The default steer table option At Steering Wheel is the option we ll use in our study gt Enter the steering wheel angles as shown below Table 5 5 Steer Table entries for the EDVSM Blow out Studies events The same table will be used for all blow out simulation events Steer Angle at Steering Wheel deg 1 00 0 0 1 50 45 0 Creating the Events Tutorial Wheel Data Ford Bronco Il Loaded x Blowout Brake Axle No Side 4 Location C Left Right Inner amp Guter M Tire is Blown Auto Start Start Time sec 3 0000 Duration sec 0 2000 Stiffness Factor J 0 1000 3olling Resistance Factor fio 0000 Cancel Apply Help Figure 5 11 HVE Wheels dialog with Tire Blow ou
14. tire forces 2 Press OK to add the selected variables to the Variable Output table The Variable Output report for the EDVSM Curb tripped Rollover event now includes the selected results see Figure 5 23 4 Variable Output EDYSM_ Curb tripped Rollover Viewing Results i Ford Bronco Ford Bronco Ford Bronco Ford Bronco Ford Bronco Ford Bronco ime sec X hf zZ Roll Pitch Yaw ft ft ft deg deg deg 6 0333 380 5 14 2 23 0 3 0 7 Ti 6 0667 382 4 14 4 2 3 0 3 0 7 7 2 5 1000 384 2 14 6 23 0 3 0 7 7 2 5 1333 386 1 14 9 2 3 0 3 0 7 73 6 1667 388 0 15 1 2 3 0 3 0 7 73 af 6 2000 3838 153 23 0 3 0 7 74 5 2333 391 7 15 6 2 3 0 3 0 6 7 4 6 2667 393 6 15 8 23 0 3 0 5 75 5 3000 3955 16 0 2 3 0 3 0 6 75 5 3333 397 4 16 3 23 0 3 0 6 7 6 6 3667 399 3 16 5 2 3 0 3 0 6 7 6 6 4000 401 2 16 8 23 0 3 0 6 73 6 4333 403 1 17 0 2 3 0 3 0 6 7 8 ACR ANR n 17 22 A ne 79 EDVSM Figure 5 23 Variable Output report for EDVSM Curb tripped Rollover displaying the selected results 5 38 Viewing Results Tutorial Trajectory Simulation Let s display a trajectory simulation for this event To view the Trajectory Simulation for the EDVSM Curb tripped Rollover event perform the following steps 2 Click Add New Object The Report Window Information dialog is displayed gt Select EDVSM Curb tripped Rollover from the Active Events list gt Click onthe Selected Output option list a
15. Description Tutorial EDVSM TUTORIAL Chapter Description This tutorial is based onthe EDVSM validation study described in SAE Paper No 970895 4 The validation study includes a curb tripped rolloverof a Ford Bronco II In this tutorial we extend this validation study by illustrating how a tire blow out at various wheel positions affects the vehicle response Like all EDVSM events the procedure involves the following basic steps l x a fe EB 2 Create the vehicle s Create the environment Execute the EDVSM event s Review the EDVSM output reports This basic procedure is described in detail in this tutorial 33 NOTE It is assumed that HVE is up and running and that the user is familiar with HVE s basic features such as using HVE s dialogs and viewers as well as the HVE Editors The purpose of this tutorial is to illustrate those features while setting up and executing an EDVSM event EDVSM Getting Started Getting Started Asinothertutorials before we get started with our current tutorial let s set the user options so we re all starting on the same page IS NOTE Most options simply affect the appearance in a viewer during Event or Playback mode However some options affect the data used in the analysis For example if AutoPosition is On the vehicle position conforms to the local surface otherwise the position is set by the Position Velocity dialog Obviously the resulting differe
16. ay bar at the rear suspension 2 Click on either rear wheel The Wheel pop up menu is displayed 2 Choose Suspension The Suspension Information dialog for the selected wheel is displayed see Figure 5 4 2 Choose Springs and Shocks The Springs and Shocks dialog for the selected wheel is displayed gt Inthe Auxiliary Roll Stiffness data field replace the existing value 0 00 with the calculated value for a 1 inch anti sway bar 1310 0 in Ib deg The dialog now appears as shown in Figure 5 5 gt Press OK to accept the new auxiliary roll stiffness gt Press OK againto remove the Suspension Information dialog 5 6 Suspension Data Ford Bronco ll Loaded Axle No 2 Right Side Suspension T ype Solid Axle ntertandem Load Transfer Goef 2 100 j 0 000 Mechanical Inertia Jounce Rebound Geometry Camber Anti Pitch Roll Steer Copy to Other Side OK Cancel Figure 5 4 Vehicle Suspension Information dialog used for selecting various suspension data groups for editing Finally let s disable the left front brake by setting its brake torque ratio to zero 2 Click on the left front wheel The Wheel pop up menu is displayed gt Choose Brake The Brake Assembly dialog for the left front wheel is displayed gt In the Torque Ratio data field replace the existing value 27 66 in lb psi with the desired value 0 0 to disable the lef
17. ay bar to the rear suspension and disable the left front brake this was done as part of the handling experiment to help ensure directional control and test repeatability To edit the color perform the following steps gt Click on the CG and choose Color The Vehicle Color dialog is displayed see Figure 5 2 showing the vehicle s current color the small black square or hot spot in the color wheel and intensity the arrow in the intensity slider Click on the hot spot and drag it to the yellow area To lighten the vehicle click on the intensity slider and drag it to the far right end of the range 33 NOTE The color chip on the left shows the current color Creating the Vehicle Tutorial Color E ditor c x Edit Sliders Options Figure 5 2 Vehicle Color dialog used for assigning the vehicle color m EJEXES i gt gt When the color is lightened to your liking press the Close button to apply the new vehicle color 33 NOTE The vehicle s apparent color may be slightly misleading because the vehicle is translucent when displayed in the Vehicle Editor The actual color will be used whenever the vehicle is displayed during Event and Playback mode Next let s change the weight and rotational inertias to account for the outriggers installed on the test vehicle to prevent rollover Perform the following steps l x a fe 2 gt Click on the CG and choose nertias The Inertias dial
18. displayed for the EDVSM Curb tripped Rollover event as shown in Figure 5 17 l x a fe 2 EDVSM Viewing Results Accident History The Accident History report displays the time and total distance traveled as well as the position and velocity at the start and end of the run Accident History EDVSM Curb tripped Rollover ACCIDENT HISTORY Total Distance Travelled ft 575 56 Time sec TITLE Position Velocity X Y PSI N tot u vel v vel Yaw Vel ft ft deg mph mph mph deg sec Initial 123 00 0 00 0 00 20 00 20 00 0 00 0 00 Final 663 40 130 46 81 18 36 29 33 54 5 59 27 87 ha ALI f Z Figure 5 18 Accident History report for EDVSM Curb tripped Rollover To view the Accident History report for the EDVSM Curb tripped Rollover event perform the following steps 2 Click Add New Object The Report Window Information dialog is displayed gt Select EDVSM Curb tripped Rollover from the Active Events list gt Click onthe Selected Output option list and choose Accident History gt Press OK The Accident History report is displayed for the EDVSM Curb tripped Rollover event as shown in Figure 5 18 Viewing Results Tutorial Environment Data The Environment Data report displays the physical and visual parameters describing the environment Environment Data EDVSM Curb tripped Rollover GENERAL ENVIRONMENT DATA Ambient Temperature Farenheit 68 00 Ambient Pressure in Hg
19. e Duration 0 2 seconds gt Enter the Stiffness Factor 0 10 gt Enter the Rolling Resistance Factor 10 l x a fe He gt Press OK to apply the tire blow out parameters Now we re ready to execute the event gt Using the Event Controller click Play to execute the event to simulate the loss of pressure at the left front tire Allow the event to rununtil the simulation terminates at t 5 00 seconds The EDVSM event is shown in Figure 5 13 IS NOTE While the event is executing watch the current results in the Key Results windows EDVSM Creating the Events HVE EDVS ial hve Options Reet UF Tire Blow out jo n 5000 0 0025 amp 8OsTt 36 3 8000 0 1000 Key F i fate Robe Roty ES Zoom 246 Doly Figure 5 13 HVE Event Editor executing the EDVSM L F Tire Blowout simulation To study the effect of a blow out at the right rear tire perform the following steps 2 Click on Add Event The Event Information dialog is displayed gt Select Ford Bronco II Loaded fromthe Active Vehicles list 2 Select EDVSM from the Calculation Method options list gt Enter a name for the event R R Tire Blow out 2 Press OK to display the event editor Repeatthe steps used inthe previous event to setup our right rear tire blow out simulation 2 Choose Set up from the menu bar select Position Velocity gt Directly enter the vehicle s initial position X 12 3 ft Y 0 ft Its in
20. e is to 1t You can print any other report using the same three steps described above 33 NOTE The Print dialog provides several options Refer to the HVE User s Manual for more information 33 NOTE The font size of both the printed reports and screen display may be edited by clicking on the Options menu and choosing Preferences Use the Font Size option list to change the size
21. formation dialog also allows you to edit the Driver Location Engine Location Number of Axles and Drive Axle s The Ford Bronco ll is a 4 wheel drive vehicle but we re going to select 2 wheel drive for the tutorial 2 Using the option buttons click each button to choose the following vehicle from the Vehicle Database Type Sport Utility Make Ford Model Bronco II Year 1984 199 Body Style 2 Door Drive Axle Axle 2 l x a fe He 33 NOTE The Ford Bronco Il is a 4 wheel drive vehicle Because it was used in 2 wheel drive mode during the handling experiments we must edit the default Drive Axle option gt Editthe default name enter Ford Bronco II Loaded 2 Click OK to add Ford Bronco Loaded to the Active Vehicles list The Ford Bronco II is displayed in the viewer as shown in Figure 5 1 EDVSM Creating the Vehicle HVE Untitled Untitled BE Ele Edi Yew Mode Setup IQER Ostons Help D G Fora Bronco tt Loaded oe lt ouo 0000 n 0000 ac dre amsomsTes2 a 8 0000 0 0333 Rete Roy oT Zoom a 450 Dolly NUM Figure 5 1 Ford Bronco Il Loaded before editing Editing the Vehicle Next we will edit the vehicle to change its color and inertias the test vehicle was fitted with outriggers to prevent a catastrophic rollover these outriggers and other test equipment affected the vehicle s inertial properties In addition we ll add an anti sw
22. itial heading angle is 0 degrees and need not be modified 2 Click the Velocity Is Assigned checkbox Enter the initial velocity 50 mph Creating the Events Tutorial RIR Tire Blowout JOK il gt x 5000 0 0025 amp 8SBOm0T 2 a 4 0000 0 1000 Rote Roy ES Zoom jJ eas NUM A Figure 5 14 HVE Event Editor executing the EDVSM R R Tire Blowout simulation To enter the steer angles perform the following steps Jj lt a 9 EB E E gt Click on the Set up Menu select Driver Controls The Steering Table dialog is displayed gt Enterthe steering wheel angles as shown earlier in Table 5 5 gt Press OK to accept the steering table Now let s set up the HVE Tire Blow out Model 2 Choose Set up from the menu bar and select Wheels The Wheels dialog is displayed with the Tire Blow out information gt Click on the Ax e No option list and choose Axle No 2 Click on the Right side radio button Click in the Tire is Blown check box The default blow out parameters for the right rear tire are displayed gt Enter the Start Time 3 0 seconds gt Enter the Duration 0 2 seconds gt Enter the Stiffness Factor 0 10 gt Enter the Rolling Resistance Factor 10 gt Press OK to apply the tire blow out parameters EDVSM Creating the Events Ba E EDVSM UR Tire Blowout JOK lt i gt 50001 0 0025 aodre ssosTtes 42 42000 0 1000 402 54 2 v 2 5i 40 3 5 a 30 16 1 n2 Q
23. m Wheel Spin Vel deg sec Sees Pitch Index Angle deg 70 00 Driveline Inertia lb sec 2 in 6 50 Ki Figure 5 21 Program Data report for EDVSM Curb tripped Rollover To view the Program Data report for the EDVSM Curb tripped Rollover event perform the following steps gt Click Add New Object The Report Window Information dialog is displayed gt Select EDVSM Curb tripped Rollover from the Active Events list gt Click on the Selected Output option list and choose Program Data gt Press OK E lt a fe EB 2 The Program Data report is displayed for the EDVSM Curb tripped Rollover event as shown in Figure 5 21 EDVSM Viewing Results Variable Output The Variable Output report is a table of user selectable time dependent simulation results forthe current event To view the Variable Output report for the EDVSM Curb tripped Rollover event perform the following steps 2 Click Add New Object The Report Window Information dialog is displayed gt Select EDVSM Curb tripped Rollover fromthe Active Events list 2 Click on the Selected Output option list and choose Variable Output gt Press OK The Variable Output report is displayed for the EDVSM Curb tripped Rollover event The table is initially empty so the next step is to select the time dependent results we wish to display in the table Variable Selection The purpose of our EDVSM study is to illustrate a rollover sequence
24. nce in initial conditions could substantially change the event 33 NOTE Some of the following options are Toggles that switch between two different modes Make sure these options are set correctly To set the initial user options choose the following from the Options Menu gt ON Show Key Results gt OFF Show Axes gt OFF Show Contacts gt OFF Show Velocity Vectors gt ON Show Skidmarks gt OFF Show Targets gt ON AutoPosition gt Units equals U S gt Render Options Show Humans as Actual Show Vehicles as Actual Phong Render Method Complexity equals Object Render Quality equals 5 Texture Quality equals Anti aliasing equals The remaining options will automatically initialize to their default conditions We re now ready to proceed with the tutorial Our goalisto use EDVSM to simulate a handling experiment conducted by the University of Missouri 6 This tutorial shows us how to perform this simulation Creating the Vehicle Tutorial Creating the Vehicle First let s add the vehicle to our case The vehicle is a yellow 1984 Ford Bronco II gt If the Vehicle Editor is not the current editor choose Vehicle Mode The Vehicle Editor is displayed gt Click Add New Object The Vehicle Information dialog is displayed The Vehicle Information dialog allows the user to select the basic vehicle attributes according to Type Make Model Year and Body Style 33 NOTE The Vehicle In
25. nd choose Trajectory Simulation gt Press OK The Trajectory Simulation viewer is displayed for the EDVSM Curb tripped Rollover event see Figure 5 24 The viewer shows the vehicle at its initial position To visualize the motion perform the following steps gt Click Play single right arrow The simulation begins and is displayed at the current Playback output interval gt Click Pause The simulation stops gt Click Reverse single left arrow The simulation plays in reverse gt Click Pause The simulation stops 2 Click Rewind left arrow with bar The simulation returns to the start gt Click Advance to End right arrow with bar the simulation advances to the end of the run l x x fe He EDVSM Viewing Results 4 Traj Sim EDYSM Curb tripped Rollover Ex a oo gt piene Bl eee Zoom gt 23 4 Dolly Figure 5 24 Trajectory Simulation for EDVSM Curb tripped Rollover displaying the vehicle at the moment of rollover Viewing Results Tutorial Damage Profiles Finally let s display the damage profile simulation for the event To view the Damage Profiles for the EDVSM Curb tripped Rollover event perform the following steps 2 Click Add New Object The Report Window Information dialog is displayed gt Select EDVSM Curb tripped Rollover from the Active Events list gt Click on the Selected Output option list and choose Damage Profiles gt Pres
26. og is displayed and we re ready to change the vehicle s inertias In the Total Weight text field replace the existing weight 3594 with the measured test value 4329 2 Ib 33 NOTE The dialog might initially display 3593 906 or a similar number because the weight is actually divided by the current gravity constant and stored as mass Extra precision results when the mass is multiplied by the current gravity constant and redisplayed gt Inthe Sprung Inertia Roll text field replace the existing roll inertia 3133 83 with the measured value 5372 4 Ib sec in EDVSM Creating the Vehicle Inertial Data Ford Bronco ll Loaded i2 x Total Weight Ib Mass Ib sec 2 in 4323 200 11 204 5372 40 2 35 90 Pitch Ib sec 2 in 23666 90 Sprung Inertia Ib sec 2 in Roll Y aw Ib sec 2 in 26100 85 XZ Product Of Inertia Ib sec 2 in 0 00 Cancel Figure 5 3 Vehicle Inertias dialog used for editing the current weight and roll and pitch and yaw rotational inertias gt Inthe Sprung Inertia Pitch textfield replace the existing pitch inertia 21680 97 with the measured value 23666 9 Ib sec in gt Inthe Sprung Inertia Yaw text field replace the existing yaw inertia 23239 0 with the measured value 26100 85 Ib sec in The Inertias dialog now appears as shown in Figure 5 3 gt Press OK to accept the new weight and rotational inertias Next let s add a 1 inch the anti sw
27. ow completed the first event Creating the Events Tutorial K il gt gt i 15 0000 0 0025 11 0000 0 1000 I o i Bs popol Rote Roy m Zoom _ 234 Dolly DONUM Figure 5 10 HVE Event Editor executing the EDVSM Curb tripped Rollover event Jj lt a 9 EB E E EDVSM Creating the Events Creating Tire Blow out Simulations The next four events in our Tutorial use ED VSM to study the vehicle s response to a loss of pressure at various tire locations during a cornering maneuver In this parameter study we will change only the wheel location at which the blow out occurs so any difference in vehicle response is attributable solely to the location of the blown tire To simplify our study we ll use the current environment To study the effect of a blow out at the right front tire perform the following steps 2 Click on Add New Object The Event Information dialog is displayed 2 Select Ford Bronco II Loaded fromthe Active Vehicles list gt Select EDVSM from the Calculation Method options list gt Edit the event name R F Tire Blow out 2 Press OK to display the event editor Now we re ready to set up i e supply position velocity driver controls and tire blow out parameters for the right front tire blow out event 2 Choose Set up from the menu bar and select Position Velocity The Ford Bronco is displayed at the earth fixed origin gt Using the Position Velocity dialog enter
28. review in this tutorial The Report Window Information dialog also includes the user editable Report Window Name text field and Selected Output option list 2 Select EDVSM Curb tripped Rollover fromthe Active Events list gt Click on the Selected Output option list and choose any of the available reports 2 Press OK to display the report The selected report will be displayed in a resizable window The following pages illustrate the reports produced for the EDVSM Curb tripped Rollover event 5 30 Viewing Results Tutorial Messages EDVSM produces a number of messages depending on the outcome of the event For a complete listing and explanation of the messages refer to Chapter 6 5 Messages EDYSM_ Curb tripped Rollover x MESSAGES The simulation was terminated because no terrain exists beneath the vehicle and a rollover is under way To continue the rollover simulation ensure that a terrain exists beneath the vehicle st Figure 5 17 Messages report for EDVSM Curb tripped Rollover To view the reports produced by the EDVSM Curb tripped Rollover event perform the following steps gt Click Add New Object The Report Window Information dialog is displayed as shown in Figure 5 17 and includes a list of the active events gt Select EDVSM Curb tripped Rollover from the Active Events list gt Click onthe Selected Output option list and choose Messages gt Press OK The Messages report is
29. s OK The Damage Profiles simulation viewer is displayed for the EDVSM Curb tripped Rollover event see Figure 2 25 The vehicle is displayed in its initial condition To visualize the damage to the vehicle use the Event Controller in the same manner as for the Trajectory Simulation Rp NOTE Because the Trajectory Simulation enables the Event Controller you must have a Trajectory Simulation open for this event in order to play the Damage Profile Damage Profiles EDYSM Curb tripped Rollover Jj lt ra 9 EB E E Rot Roty Zoom _ gt 27 0 Dolly Previous Vehicle Figure 5 25 Damage Profile for EDVSM Curb tripped Rollover displaying the vehicle at the end of the simulation EDVSM Viewing Results Printing The final step is to printthe above reports Printing reports is simple All you do is choose a report and print it For example gt Click on the dialog header of the Variable Output EDVSM Curb tripped Rollover report The dialog headeris highlighted and the Variable Output window pops to the top of the display if it isn t there already indicating it is the current window gt Click on the File menu and choose Print The Print dialog is displayed allowing the user to select from several available print options 33 NOTE Alternatively you can click on the print icon in the upper menu bar 2 Press OK The Variable Output report is printed on the system printer That s all ther
30. t front brake The dialog now appears as shown in Figure 5 6 gt Press OK to accept the modified brake torque ratio for the left front wheel The vehicle is now ready for use in our events Using the viewer thumb wheel rotate and look at the vehicle Note that the thumb wheels rotate the vehicle about the viewer axes not the vehicle axes Creating the Vehicle Tutorial l lt a fe EB 2 EDVSM Creating the Vehicle Spring and Shocks Axle No 2 Right 2 xl Springs Aux Roll Stiffness in lb deg 131 0 0 JL p Roll Center Height in Lateral Spring Spacing in m Shock Absorbers Damping at Wheel Ib sec in RBRM 8 450 Coulomb Friction lb 100 000 Friction Null Band in sec QE 0 000 Cancel Figure 5 5 Springs and Shocks dialog used for editing the current auxiliary roll stiffness due to the anti sway bar Brake Assembly Ford Bronco II Loaded Axle No 1 Left x Time Lag sec q 0 0000 Time Rise sec SA 0 0000 Brake Assembly Type Generic Brake E dit Push out Pressure psi nmn 0 000 Brake Torque Ratio in Ib psi D joo Proportion On Pstart psi o0 GE 10 7 Antilock On Antilock Effecti
31. t Model option 2 Press OK to accept the steer table Now let s set up the HVE Tire Blow out Model gt Choose Set up from the menu bar and select Wheels The Wheels dialogis displayed with the Tire Blow out information see Figure 5 11 2 Click on the Ax e No option list and choose Ax e No 1 Click onthe Right side radio button Click in the Tire is Blown check box The default blow out parameters for the right front tire are displayed gt Enter the Start Time 3 0 seconds gt Enter the Duration 0 2 seconds gt Enter the Stiffness Factor 0 10 l lt a fe He 33 NOTE The Stiffness Factor reduces the tire s radial tire stifiness cornering stiffness and camber stiffness gt Enter the Rolling Resistance Factor 10 33 NOTE The Rolling Resistance Factor increases the tire rolling resistance 2 Press OK to apply the tire blow out parameters EDVSM Creating the Events HVE EDVS Rote Roy ES Zoom 246 Dolly NUM Figure 5 12 HVE Event Editor executing the EDVSM R F Tire Blowout simulation Now we re ready to execute the event gt Using the Event Controller click Play to execute the event to simulate the loss of pressure at the right front tire Allow the event to rununtil the simulation terminates at t 5 00 seconds The EDVSM event is shown in Figure 5 12 I amp S NOTE While the event is executing watch the current results in the Key Results windows To study
32. the Bronco is not visible in the viewer use the Dolly thumb wheel to dolly back until the Bronco becomes visible Then pan the viewer until the vehicle is in the center of the viewer and dolly back in a good exercise in using viewers gt Click onthe vehicle s X Y manipulator see Figure 5 8 wait for it to turn bright yellow indicating it has been selected and drag it to its initial position X 123 ft Y 0 ft Its initial heading angle is 0 degrees and need not be modified NOTE Be sure to keep the mouse button depressed while you drag the manipulators 33 NOTE Adjust the viewer by dollying back using the Dolly thumb wheel until you can see enough of the entire scene Creating the Events Tutorial covsw amp 80sTt 2 minorii C Yaw depre 000 Ashy Rots Roty M am Zoom 24 6 Dolly d Figure 5 8 Vehicle positioning using the HVE Event Editor The manipulators can be used to drag and drop the vehicle into position NOTE To select the X Y manipulator the viewer must be in Pick mode as indicated by the highlighted arrow in the upper right corner of the viewer see Figure 5 8 Rp NOTE If you cant position the vehicle at the exact coordinates simply enter them in the dialog in fact it s often easier to directly enter the coordinates using the dialog J lt a 9 LE E E gt Click the Velocity Is Assigned checkbox Enter the initial velocity 20 mph
33. the effect of a blow out at the left front tire perform the following steps gt Click on Add Event The Event Information dialog is displayed 2 Select Ford Bronco II Loaded fromthe Active Vehicles list gt Select EDVSM from the Calculation Method options list 2 Enter a name for the event L F Tire Blow out 2 Press OK to display the event editor 5 22 Creating the Events Tutorial Repeat the steps used in the previous event to set up our left front tire blow out simulation 2 Choose Set up from the menu bar select Position Velocity gt Directly enter the vehicle s initial position X 12 3 ft Y 0 ft Its initial heading angle is 0 degrees and need not be modified gt Click the Velocity Is Assigned checkbox Enter the initial velocity 50 mph To enter the steer angles perform the following steps 2 Click on the Set up Menu select Driver Controls The Steering Table dialog is displayed gt Enterthe steering wheel angles as shown earlier in Table 5 5 gt Press OK to accept the steering table Now let s set up the HVE Tire Blow out Model 2 Choose Set up from the menu bar and select Wheels The Wheels dialog is displayed with the Tire Blow out information gt Click on the Ax e No option list and choose Axle No 1 Click on the Left side radio button Click in the Tire is Blown check box The default blow out parameters for the left front tire are displayed 2 Enter the Start Time 3 0 seconds gt Enter th
34. the steering wheel angles as shown earlier in Table 5 5 gt Press OK to accept the steering table Set up the HVE Tire Blow out Model 2 Choose Set up from the menu bar and select Wheels The Wheels dialog is displayed with the Tire Blow out information gt Click on the Axle No option list and choose Axle No 2 Click on the Left side radio button Click in the Tire is Blown check box The default blow out parameters for the left rear tire are displayed 2 Enter the Start Time 3 0 seconds 2 Enter the Duration 0 2 seconds gt Enter the Stiffness Factor 0 10 gt Enter the Rolling Resistance Factor 10 l x a fe He gt Press OK to apply the tire blow out parameters Now we re ready to execute the event gt Using the Event Controller click Play to execute the event to simulate the loss of pressure at the left rear tire Allow the event to rununtil the simulation terminates att 5 00 seconds The EDVSM event is shown in Figure 5 15 IRS NOTE While the event is executing watch the current results in the Key Results windows We have now created four events simulating a tire blow out The only difference in these events is the location of the blown tire Thus any differences in vehicle behavior are attributable solely to the location of the blown tire EDVSM Creating the Events Observations Note the vehicle is in a right turn thus the vertical tire force is shifted from the right side to
35. to our Key Results window gt Click Wheels Axle 1 Right from the variable group list The Variable Selection list for the right front wheel is displayed gt Choose Delta from the Variable Selection list gt Repeatthe above steps to choose Delta forthe left front wheel gt Press OK to add the selected variables to the Key Results window EDVSM Creating the Events Variable Selection EDVSM Curb tripped R E3 Object Name Ford Bronco II Loaded Current Variable Tires amp xle 1 Right Quter Dutput Groups Variables Kinematics P x tire a Kinetics y tire Accelerometers Accel 1 z tire Accelerometers Accel 2 x tire Accelerometers Accel 3 Accelerometers Accel 4 Accelerometers Accel 5 Y tire lt tre 2 e Mx tire Tires Asle 1 Left Outer My tire Tires Axle 1 Left Inner x Mz tire x Clear Selection Cancel Figure 5 9 Key Results Variable Selection dialog used for selecting variables to be displayed in the Key Results window Now we re ready to execute the event 2 Using the Event Controller click P ay to execute the event Allow the event to run until the vehicle strikes the curb and rolls over 33 NOTE The simulation terminates with an error because the vehicle travels beyond the terrain boundary The EDVSM event is shown in Figure 5 10 I3 NOTE While the event is executing watch the current results in the Key Results windows We have n
36. veness 22 100 0 50 T Copy to Other Side Cancel Figure 5 6 Wheel Brake dialog used for editing the brake parameters for the left front wheel 5 8 Creating the Vehicle Tutorial 33 NOTE Remember HVE s 3 D viewers have 2 modes Pick and Manipulate the icon in the upper right corner of the viewer displays the current mode In Pick mode you can use the thumb wheels to adjust the view In Manipulate mode you can use the left mouse button to rotate the view and the middle mouse button the pan back and forth Refer to the HVE User s Manual Overview Window Manager Basics for more information about using HVE s viewer controls l x a fe He EDVSM Creating the Environment Creating the Environment Now let s add the environment 2 Choose Environment Mode The Environment Editor is displayed gt Click on Add New Object The Environment Information dialog is displayed gt Using the Location Database combo box choose Jefferson City Missouri USA The latitude 38 58N longitude 92 20W and GMT hours from the prime meridian 6 00 are displayed for the selected location gt Edit the date and time of the experimental study 7 11 93 and 1500 respectively gt Edit the angle from true north to the earth fixed X axis in our environment 165 degrees IS NOTE The Latitude Longitude GMT Date Time and angle from true north are used to position the sun in the scene

TUTORIAL

Contents

Download Pdf Manuals

Related Search

Related Contents