Drop Tower Design - Worcester Polytechnic Institute
Contents
1. Pa TEL AR 1010 cc bo ml ri ba FRISK DE M OF IH 3 Figure 21 Base Top Plate 42 D HART SAN L barr SM LES Worcester Polytechny Bwtimnne TITLE Top of Base Box ALE DS Ho A base top SCALE 18 WEISHT 143 85 REM SHEET 1 SF 1 Figure 22 Base Short Side 43 Figure 23 Base Long Side 44 Ge Lis me IN kees ICON SEI IE ICON CI CI E fem NIE EE mc 16 ne Inrnernmal acer aon ring Flora Oe pe Ise le Kc TE ESA EN ER w aie es ES hHHT HP TD DE HH ED nen force ster Polytechnic Iretipite SC gen mir kde a hL Km I SA KAREL KE d stucturdal bose Assembly Ik Perr LINTE ho A EL Sag MALL r APS FT ENE Pen in SPP DWG k DA mr LL Ed RI YN Y ki ERC C Dose a mob And Ar PA MG pr bM I r I Figure 24 Tower Base Assembly 45 Figure 25 Drop Platen with Penetrator 46 d COSMETIC UHI ESS GI SER EE SPECIFED r tt E DANE Worcester Polytechnic Institute DAE HE CHE ARE H IWC n ES Mee SMF 222372015 VEME RA HC EE ANC AF AACHE DN CHECCED TITLE GHE ACE DIE kaki D re AP Latch Mechanism WC FFF Keren Gs Hook For Platen FEGFHETA EY AHC HA CE NI AL IGE KA HO BD FER ASAL TI ae Int lI yu 1 CS CC MED N IHE rn JER EI DRAM HC E HE SG E FROFERIY G lon Sober ber pe SEE DWG NO REV PEERI CORR UY Arne HERES AKP Sl REEFRODCIDN H FE AS ao HHE H A Platen latch WAN HAH THE FIER PE RESO CH SE LET ee2. Design of a Cost Effective Drop Tower for Impact Testing of Aerospace Materials Major Qualifying Project Submitted to the Faculty of WORCESTER POLYTECHNIC INSTITUTE In partial fulfillment of the requirements for the Degree of Bachelor of Science Report Submitted Project Advisors Maria Chierichetti Anthony Linn Report Submitted by Shawn Ferrini Latthapol Khachonkitkosol Michael Strauss 3 9 2015 Abstract The unique challenges presented by the high performance and stringent safety demands of the aerospace engineering field require advanced materials These materials are constantly being developed and refined and a thorough knowledge of their properties and behavior is necessary before they can be put to use Energy absorption is an important mechanical property that is most commonly evaluated by conducting impact tests This project has developed a low cost reliable guided drop tower for impact testing of novel aerospace materials The project team has produced a complete design along with a user manual and bill of materials It is anticipated that the final design will used to fabricate and assemble a drop tower for future research Acknowledgements We would like to thank the following individuals and organizations for the support they provided our team Without their tireless help and support our project would not have been possible e Professor Maria Chierichetti for her advice and insight in the early stages
3. It is also encouraged that future teams measure and record the maximum impact energy and velocity with the effects of friction at each different drop weight setting for reference Materials selection is a vital process in Aerospace Engineering testing materials is a way to ensure structural integrity in aircraft Overall the project team feels confident that the design having gone through many detailed and careful design iterations will allow for a functioning impact drop tower to be constructed inexpensively and used for aerospace applications in the future 33 6 References 1 About ASTM International Online Available http www astm org ABOUT overview html Accessed 10 06 2014 2 Gooch Jan W Charpy Impact Test Encyclopedic Dictionary of Polymers New York Springer 2007 179 80 404 449 450 Online Available http au4sb9ax7m search serialssolutions com ctx_ver Z39 88 2004 amp ctx enc info 3Aofi 2Fenc 3AUTF 88 amp rfr id info sid summon serialssolutions com amp rft val fmt info ofi fmt kev mtx book amp rft gen re book 20item amp rft title Encyclopedic Dictionary of Polymers amp rft atitle Charpy Ilmpact Tes t amp rft date 2007 01 O1 amp rft pub Springer amp rft isbn 9780387310213 amp rft spage 179 amp rft epage 180 amp rft externalDocl D 3042801964 amp paramdict en US Accessed 10 6 2014 3 Subcommittee D10 13 Standard Test Method for Dynamic Shock Characteristics of Packaging Material online Ma
4. PEERI COMA HA KAE HERES E OH KI ED AFF AIR DO dolce D AA SCALE 1 1 wEIGHT O 24 SHEET OF 4 3 Figure 26 Latch Mechanism Hook 47 UTES GInE Sd EE S FEIC RED LR E DIE Worcester Po bote c pic Instibite LR ANN SAV k a eos Dhi EEG HE ARE IH HOS IG ERA HC E ANCU AR awl DEI CH EC LED TITLE CHE FC E DEC ka he EF AFFE MG PIACE DECIMAL DE ee Sel For P enetra tor KOR LID GEK er FR OFF ICA EN AMD ZO TI MAL A FM kim T YI gt FRP TOP arab COR KIT I TEK a FTE LA DE WEG R TET Or EE BEEN Ar 1080 ler a SEE DWG HG ZH SFF CO REA bY KARE bE Ab Y See t t t EFO DUETO FAET DF aga WHOIT MR Eb L es A DENE FOTO 5e WEHO Ur TREF WEFITH FER Bob OF ki ak iff CO aet A bY barli BIEN li iyan A EON A TA SALE TT WEISSHTO Z3 SHEET1OF1 PE AI 4 5 Figure 27 Penetrator Collar 48 r 6 13 SECTION A A SCALE 4 PRO RACE dho COhIDIRIAL TRO BIO Ahab Cob Faro b TAS DE s EG litr SOT FEOFTE OF Chil CorFA PY b aser RIEN ABY FTFEGDLIC Ok b PART DE ada Whole WW Fu OUr OW EF TH ATRESOLH AP B t CORPA RT b ae HIET E FPROPEFIO HEST iir A FFI a Ob A UHI 5 CA H EP EE 5 PR IE D D ke Tiii APE IK BERT E rol tab ert ARGUE wach 0510 AbrFIserbrokal PWO AACCorelsal 8 l LHTLETH Mo APR HIG APRE b TTFAT Ofori DA FOIE SO KG FOR aiHT via HATE I 10 N Mav mn Cor HT Ti THEE DO OT Cal T DEA MIRO 2 Figure 28 Latch Mechanism Platen 49 har
5. buildings There must also be a method of dampening the impact transferred to the floor of the lab Figure 3 Steel Plate Base The first iteration was a 1m X 1m X 04 m 39 4 in X 39 4 in X 1 5 in steel plate In order to lessen the impact on the lab floor rubber loading dock bumpers were designed to be used as feet underneath the steel plate These rubber bumpers are typically used for loading docks to protect semi truck trailers from damage This design met the requirements for weight but was ultimately rejected The steel plate was far too expensive costing approximately 1200 This made this iteration of the design infeasible for use in this project 19 Figure 4 Rubber Dock Bumper In order to cut down on cost the project team decided to use concrete to attain the necessary mass Premixed concrete is available for 3 75 per 80 Ibs This resulted in a significant cost savings approximately 95 Pursuing this design created a host of other problems however Russ Lang the supervisor for the civil engineering labs at WPI was a consultant with the project team in concrete design Pouring a base of this size would require rebar reinforcements and a very sturdy mold Because concrete cannot be machined like a steel plate can precisely attaching the vertical components of the rest of the tower would become very difficult To counteract this problem the design included steel square tubes sunk into the concrete that would act as sleeves for
6. guide rail design The three initial designs were all created under the assumption of a system of two parallel guide rails attached at each end of the drop platen In Option A the drop platen was composed of a top and bottom plate The bottom plate was created with machined grooves to fit four rotational bearings where the guide rails would come through and the top plate acted as a locking mechanism to keep them 25 in place The second of the initial three designs Option B switched from rotational bearings to linear bearings which were to be set into the main plate of the platen and held in place by two smaller plates which would be fastened over them Option C was the design chosen to move forward and features linear bearings in flange mounts attached to the top of a thinner plate This design was chosen due to its relative ease of fabrication use of linear bearings and light weight All three initial designs included tapped holes on the top surface to attach accelerometers for data acquisition as well as threaded rods upon which weights would be fastened to vary the platen mass Figure 10 Preliminary Drop Platen Designs 26 Figure 11 Optimized two guide rail design During the design review process concerns about hitching were brought up In order to prevent this a spring loaded bearing assembly could be manufactured or two more guide rails could be added the latter was chosen for simplicity and ease of manufacture The
7. d ba TIRER DO yon UCA O A 3 Figure 19 Caster mounting Plate 40 HE LANE Worcester Pobtechhi Irstibite SAN L Sloe Sols TITLE Caster Mounting Flate SEE Bus He R EW A bottom long piece SCALE 1 5 EIGHT ODO SHEETI OF I 1 AO HESS CHERY BES FEC HIE D r r DIE ras Mal add ng DIMEREIOHE ARE IH CHES DRAIN Senk YA DFZONS Es HEN ERA MCES e WPI AMC AHA n 1 DP EF TALE Z ME PLACE DECK a0 pACAFFF F T HO PLACE DECI 2005 SVEIN a EE MAKE APPR GER Mounting Plate FROFAL AEN RD crin M l A FI kann Yds gt ThE Rat GEN arah CORT Ia TEK t ATTE Lal DE wln Teror FEDFIEIY ar AR 1010 Zezi hrs eeo ba SIZE BWG Ho RE BSCE CO FAB Y RAW DRIED Ak Za botton edge lang FTRODUCTAR h FAR GE Ad Mar FE Eb A W Fh OUT TET WAT ETERNO AT i lees ZbafbR GO FAB Y b ART BIRT li PRO BITE Mc pG 401 3At US SCALE 18 WEIGHT 22 07 SHEET 1 OF 4 3 1 Figure 20 Leveling Screws Mounting Plate 41 FEOFFEF EFY MD COMO CHAL rRPIROR ka MH CORT Ak D b THE DE s RO E RAP SOU FFUFTETY OF ESE CORK PART RAW PRI ARY ECFOGUC TOL b F AET OR as A who F A SY WEbOUr Tar WER Tt FAY Bibb AP Bile C On Fa bY b ar PRP E FEGHIF TO A AO A 29 Sv F Bt A AA Ax N UHI ES GIH E POEL SPEC FED D e Cbs I hZ ART Ib IBC ES ia OT be Mi Akaf HAD EDI BK EIS GF R RIR AI GG rwn B XGP OCokal l CHF CETO Peo A FEE HIG APRE E TENT Cae PRIO Da TON FA HEHE AT sik Yl CORTA S
8. mass that reacts in an opposing manner to the forces produced during the impact of the dropping platen on the impact surface must be at least 50 times the drop mass Taking into consideration the load that the floor in the Aerospace Engineering Lab would be subjected to and the need to move the tower in the future a maximum mass of 500 kg 1102 Ibs was chosen This means that the design can have up to 10 kg 22 1 lbs of drop weight which is the same as that of the commercial model IM1 P In order to achieve the weight of 500 kg in a cost effective manner concrete will be used in the construction of the base Maximum drop height of 1 5 meters 4 9 feet In order to generate an ideal impact energy in the same range as IM1 P without using any height or velocity augmentation system such as pneumatics or springs the total tower height was chosen at 2 meters 6 6 feet which can easily fit in the lab and maximum drop height of 1 5 meters were used This height is advantageous because it will easily fit in 16 the lab and deliver drop energy on par with the commercial drop towers Using the kinetic energy equation the ideal velocity and ideal maximum impact energy in ideal free fall were calculated v 429h KE mv Ideal velocity of 5 42 m s 17 8 ft s and maximum impact energy of 146 9 J 108 3 ft lbf were obtained Due to the low velocity air drag on the platen becomes negligible Moreover every effort will be made to
9. of this project o Professor Anthony Linn for his attention to detail and design experience e Russ Lang of the Civil Engineering department for his help in planning the concrete design e Professor Don Pellegrino of the Civil Engineering department for showing us the drop towers in his lab and advising us in specific improvements to incorporate Kevin Arruda who provided invaluable manufacturing advice e Worcester Polytechnic Institute for presenting us with this opportunity Authorship YLS an AENG E ape t to ba nal fa ab ti ti tt EN TK AA ta ER TAN ER op a kn m e piye akote pen et a oi Okipe ent AAN e Strauss TLD Strauss TENNE Strauss EES YON S rn Strauss chapter TIVE WE LO ME Strauss Chapter 2 Background Research Khachonkitkosol Ferrini Strauss SCLU OLL A EEE Ferrini UN NN Khachonkitkosol OC E AER RF AA Strauss Chapter 3 Design Process sssccsssssrecsonssscucnsssesecussectonesscneoussestenssscnenes Khachonkitkosol Ferrini Strauss SECHHON e e BE Khachonkitkosol FINN NNN Ferrini SECUOLI 0 5 e e ene Strauss Chapter 4 Conclusions and Recommendations Y YY AAA AAG LLY LLALL LLA FL i nio Khachonkitkosol ee Ee te Khachonkitkosol Ferrini Strauss All team members participated in the revision and editing of all sections Table of Contents e e 1 MONT 2 TEN 4 TENNE 5 TETT NN 6 Ek MINN 7 Zo BE MENN 9 2 1 Introduction to types of Drop Tests 9 2 2 INN 10 2 3 Commercially Available Drop Towers an aen
10. the drop The drop platen needed to be adjusted to accommodate the new quick release The final quick release assembly is pictured below and a diagram of the latch mechanism can be seen in Appendix D 3 7 Safety Considerations When working with drop towers there are several important safety issues that need to be addressed The most obvious issue is samples shattering upon impact Another issue is that when placing and adjusting the sample on the impact surface the drop mass must be suspended above the surface It is necessary to design safety systems and procedures to address these risks To address the issue of shattering samples the project team decided to install Plexiglas on the four sides of the tower to prevent shattered test materials or parts from flying off during impact This will contain any debris and protect any instruments or people who may be in the lab The project team decided to use a self locking hand crank winch and pulley system to raise and lower the drop platen The pulleys will be attached to the top of the structure supported by four aluminum beams For safety during loading the initial design was to use stopping pins in the guide rails to stop the drop platen in the event of the hand crank failing This method would require holes bored in the guide rails and may interfere with the drop motion and the bearings In order to avoid this issue PVC pipes of the same length as the guide rails with a length wise channel cut into
11. them are placed over the pipes to catch the drop platen The pipes are a failsafe in the event that the quick release or winch lock failing Inserting these pipes underneath the drop platen will ensure that the drop platen does not fall onto the operator underneath 29 3 8 Instrumentation The goal of the proposed design is to be able to measure the energy absorption of various aerospace materials The instrumentation for such measurements has been considered during the design process and can be implemented in future projects To measure the energy absorption of a material the area under the stress strain curve must be calculated This means that both the stress and strain values will need to be measured during testing F o A Where A is the area of the impact of the drop platen on the sample which is a straightforward calculation based on the size of the impactor being used The impact force can be calculated using an accelerometer and multiplying that data by the mass of the drop weight and the strain on the sample can be directly measured with the use of strain gauges The gauges need to be connected to a Wheatstone bridge assembly to pick up on the small changes in voltage created by the physical strain on the gauges All of these measurements will be collected by a National Instruments Data Acquisition box and processed with a LabVIEW code Predicting the peak acceleration caused by the impact depends on numerous factors and ca
12. with a wing nut fastening it on top The sample mounting area was then redesigned with the improved sample mounts standing 0 875 in The grooves to guide the platforms were rotated to stretch from corner to corner on the platform to save space and now include a milled slot to fit the t slot bolt This t slot bolt will run up through a hole in an extruded section on the back of the structure and help provide adequate rigidity for the sample The shortening of the sample mounts allows for a more secure mounting of the sample than the original design which would have either caused horizontal retreat of the platforms or a moment to be applied causing bending in the threaded rod In the new design a hole is drilled in the center of the 24 mounting plate in case of sample penetration The hole will prevent the impactor from striking the plate directly causing damage to the penetrator Figure 9 Finalized sample mounting design 3 5 Drop Platen Design Essential to every drop tower is the drop platen or surface to be dropped onto a designated sample Several design iterations were performed in order to develop a platen that was rigid to provide accurate data lightweight to provide more customization of drop mass and resistant to hitching Initially three preliminary options were created under the assumption of 2 guide rails a secondary phase moved forward with a two rail design and ultimately the platen was modified to accommodate the four
13. 37 Figure 17 Mounts for Leveling SCFEWGS 0L00 ttieeeeoteeetttteeaetoteaaetttoeeatoooeeesooooeesoooooeosooooeosoooooooooooonoooooooooooooonneoe 38 Figure 18 Caster Mount Cross Beams teat aaa taa teat teat aaateaeteaetoesosesoseoosesoseoooeoooeooooooooooooosoonooooen 39 Figure 19 Caster MOUNTING Plate vase 40 Figure 20 Leveling Screws Mounting Plate 41 Me eTO E EE 42 FIEUKFE TOI 43 ENN 44 Fe TANNER 45 Figure 25 Drop Platen with Penetracion 46 Figure 20 Lateh Mechanism HOOK tos 47 SPAN P Penetrator Colt EEE EE 48 ehh 49 Figure 29 Quick Release Mechanism Assembly sees eee eee eee 50 Fe TVEN 51 Figure 31 Three Quarter Inch Penetrator sion GL s ke GNU duU CG GG GBF 52 PE ee 53 Figure 33 Drop Platen Drawing NE EE EEE RE 54 Figure 34 Quick Release Assembly Model 55 Te 5 Sample NI OU M treo 56 Figure 36 Sample Mounting Plattform 57 Figure 37 Mountne Plate Standoff ee 58 Figure 38 Sample Mounting Platform Assembly sss sees eee ee eee ee eee eee 59 Figure TNT 60 Figure AD Top Assembly NELS 60 Table of Tables Table 1 Low to Medium Energy Drop Towers Table 2 Medium Impact Energy Drop Towers Table 3 Sample Materials and Predicted Peak Acceleration 1 Introduction The aerospace engineering field is driven by high performance Almost every component of an air or space craft is required to perform under more extreme conditions than any other To handle the stresses temperatures and
14. 9 00 UHIESS CIHER EE SF EC IVE D DIE oe Polytec EE DWA HENDE ARE H IHC HES DAA H 2016016 ION ERAMCES TITLE CHEZ LED ACA ac HA Dan Z CHE FACE DECHKASI DS ERED PRR S j Yi PA t Pr FACE DECIA 20 15 a O LI n IN SHO FFF PI t ETRET G TO m PP Ki a FROPEE A FY AMD COMO LR MAL r 5 a nITPABDLIBO EE ASH Yla Z IE Thr BD ATEB CO bak H TENG N AFF DE WEA R TET SIT FE FTETY oF A DA TKa ETAN dan e SEE DW HO REV KIPER FabYbakCEIEC Aaby D A new sample mounting plate ETERO DUETO IK FART DE aga WhOIT TH EK WIrKA Ur rK P WPFFTH ETES ES k AP ME oe a SCALE 18 WEIGHT 47 72 SHEETI OF I FrFOREFrO AFR AND DD dl YO A 1t DRA Yn 4 3 1 Figure 36 Sample Mounting Platform 57 LH LES THERE E5 FECIFED HAA E DALE Worcester Polytechnic Institute OM EG OG AREH NGC nE DRAW H SWE 27112015 G ERA HC ES TITLE AHCU AR MAT Ha D EEG EE Mounting Plate HIERFRE NC EGMETTO GA Sta ndoftts PROP HART A HE C OMA GENT AL FER TI DOGMER AMICI FER ASAL TI as Com ES I HE HARI DH COM NED H KE m ERA SEE DWG NO DRAM HC E HE SOIE PROPERTY GL Cair Carman reel sole A lt IHSERI OOA FAHY HAAE HERES AKT fet mounting plate ris er PEFRODUCION H PARLOR ASA HE EHEH f HI Me L nG THE RLE PERMESKOH DF HER Aar lt IRE VI OCRA FA HY Haat E H EFE E PROH EAED AFFI CAICH DO HOT SCALE DRAM IHC SCALE 1 1 WEIGHT 1 21 SHEET 1 OF 1 4 3 ct USED G v L Figure 37 Mounting Plate Standoff 58 Fig
15. ED AFFI OA OH 4 Oo Y UHI ESS CHERY BE SPEC FIED DIME ME OHE AR E IH IMC HES SECH VIZE FAI ES SHC ULAR MATH E OI CHE PLACE DEC kak DZ IWG PLACE DECIA DIS CHECCED EMO A FFF Mh AFFE HIEFFREI CEGWE IF E GA IGE FA CIR FER AS METT AS rat ERE I DED bay Cor EHIS FHE H USED CH OS KOU 504 1 E D f r HC 3 Figure 33 Drop Platen Drawing 54 Ii R10 By Ha nE DA IE SMF 2 23 2015 TITLE Worcester Polytechme frs bate Drop Platen SEE DWG MO A final platen SCALE 18 WEIGHT SDS SHEET OF 1 latch me hook Figure 34 Quick Release Assembly Model 55 FROFRETART ANE OS HR DE NAL THE I HR ID OCH 14 HED HI HE DPA HC E THE SONE PROPERTY CH TREE RI CORA MY HAME HERES ANT PERRO DUZ ICH H RART ORAS A HOE PAU Int RE FER ES CH GL FE EF COMPA HAME HERE E FPH EED HEKI ASSr GPP AI KTH A USED GH LHLESS THE RVWRE PESIRED D MES CHE AREH HOHES LEM ERA HC ES ARCA MAC Ka OF MT CHE PLACE DEC kati JD PG PLACE DECIA DIS IMT EFFFEI CRE IRL GERA MOI FER JASANE Tla Z ra EFRI Cor Carpon Sreel HHE n GS HOT SCA TE DRA HC 3 56 DRA H CHECCED EMC PER mi AFFR Figure 35 Sample Mount NAA R DANE SMF 2011720 12 Worcester Polytechme Ins thite TITLE sample Mounting Platforms SEE DWC NO A new sample mounting platforms REV SHEET 1 OF 1 SCALE 1 2 WEIGHT 1 54 LO 26 XIS Ma LI s it LA 1
16. GITEAK Gh G FOR sim Yl Z co EHIS FRP IRTO ER ATIOH LIF TAIFTD Ik THE bi ATTELAI Dn Fa wmRu ETH SOT FRQFCFETY ar For Coiber Pc El ho L SEE DWG Mo 2 RES lt m rg CORFA bY b ARKE Akt Hi EFEO LUC ok FAETUFEAI a WhoIT A IV D OC L MIR OUr rer WFFFrTH Pe Hil OF GENEE APPA IA A SCALE1 1 WEGHTO 44 SHEETI OF FEOREFIO TH Eb 5 4 3 Figure 31 Three Quarter Inch Penetrator 52 FROFH MARY ANG OHA GE NIG L THE THEO FWS OH OG HA JED MIKE DRA HO E THE SOLE FAOGFER T G SIRE TI COWRA nt HERE Ar REFRGDUC ICH H FART GRAS HOE PAG Int RIE FERYAES Dy GL FE EFI COM Hr HAME HERE E FOH BIED HEX 4550 APRIL ANKH 4 LUA LESS OT HER WUE SPECIFIED DHA EKS GHS A FE IH IWC HES IG ERA ME ES AC K MACH p ap GHE FACE DEC MAI DS IWG FACE DEC MAL Lle MIE RFRE CECE RIC ITER AAC KM FER SSE TI as A ER L Plain Corgan Sreei HHEH USED GH DO KOUT SAIE DREAM HZ 3 HLS mE pele Worcester Polytechme Institute D RANU H SE 25225014 CHECCED EHC AFFR MAH A FFR DA TOMME HIS 1 j Leg ie cy i VA ES kJ n Figure 32 One Inch Impactor 53 TITLE One Inch Impactor SEE DWG Ho REV A impactor SCALE 1 1 WHGHT O 53 SHEET OF FR FHETART AND TO KR GE ATLA THE MADRAS IRC GIH AHED N IH E ORAM ACS E ln E SOR PROPER CA KE ERT CORA RAI HAL HERES Ar FEFRGDUCID H PART GR AS nG E PAUL Inte Rtl El FER ES DH GL KE ERT CGA Fer HAME HERE E FRGHJEL
17. L Tr ER HF GES Bes PA ii ea al a YF SS Cc H nal rower a ie m nl CYD CD ABA A ROS Kne age DER CO sr net Call Ila WAG br kITr LAT I 1 T D S d J I Figure 15 Full Tower Assembly Drawing 36 Figure 16 Tower Base 37 Figure 17 Mounts for Leveling Screws 38 UHIESS O MERA EE SPECIFIED HAE DAIE Worcester Polytechruc Ire ttute DFAEHSIOHNE A FE MICHE DR AMI d SE 210 20 ES IC ER II ES TITLE A OUR MAC n 2 DON ENE p ooe Wima A EE Caster Mount IK TEREN LOU H MEL Qu Cross Beg ms FROFALA FY d RD C G RID tR rW L TO IRAK CIRO FTE Aim Yla S COME HIS TRO IFI ORR ATM b COblABIO Ib ThE KN AFF SIZE CU HCH REM Ghawho li FRE GON ORGY ar 2211010 Zeg El bro died ba ahir C Owbabybanwfbfbtfi ski Amat Ce Yi ag a A bo torr short piece EIPEO DUCTOR Ik PART OF Ai A wk otr WEH OUT FRP WEFT FW slob Ar OPA EET GE Arr DO mg Ait Drin SCALE 1 8 WEIGHT O55 SHEET 1 OF 1 4 3 1 Figure 18 Caster Mount Cross Beams 39 PFROPAL AE AO CO ADA HAL HTF IKI DEK AMOH COR BID Ik THE DEAMIBO 15 FRP SO IF FRAPFTT ar JESSIE CO REA bY BARD BCE ABY MFERODUCNO b FART OR ad 5 wk oir WFR OUT THI WEFITH FfF Blob OF USE CO REN KY Ba WC BCE E FED FIEFTH ARF Fou A U HIESS OTHER EE S FEC EE D DWAE HE DE ARE IW FACH EE DEA H KC ERA LC ES ARM A R ACA D XT CHE AACE DECHASI DS FG FACE DECHASI IS CHECCED EHC AFFE MIKS AFFE PEF GRO HT TEL TO IF En ELIO FE age Ys gt Hi ATTF Ls I MA ID IH cc br ik
18. an anana nenen n anana anana n anana anane n anana arena n eee 11 2 4 civil Lab Drop TOWET S EEE KG a e ak aj Aah a a a EE EE 14 3 DNO 16 3 1 Important Design Decisions and Tower Parameters sees eee eee eee eee eee eee 16 3 2 PENN 18 3 3 PENN 18 3 4 PENNEN 23 3 5 Drop Platen D SIN A EEE EE 25 3 6 Quick Release pT pon S EE E 28 3 7 SM CONS 19 e EE 29 F NNN 30 5 Conclusions and Recommendations for Future Work sss sese sees eee eee eee eee 33 o 0 EE 34 Appendix GN B DE E 35 Appendix B Listo Material EEE EE EE DN 61 Appendix C User Manual EE EEE ET 62 Appendix D Quick Release Latch Mechanism Diagramm 66 Table of Figures Figure 1 Previous MOP Drop Tower varende keen 14 Figure 2 Close VIEW of Drop Pla CO EE DG O kk ie kinbe kn on kata dd 15 Pee ENN 19 FISURA Ri BBEF DOCK 0 errrssniinna nna E E 20 Figure 5 Box filled with Concrete sss esse 21 Figure 6 Third Iteration Base Assembly Design sss eee eee eee eee 22 Figure 7 Final SD EEE EE EE UU UD TNG 23 Feen Sample NON Me 24 Figure 9 Finalized sample MOUNTING design 25 Figure 10 Preliminary Drop Platen Designs sss sese eee eee ee eee eee 26 Figure 11 Optimized two guide rail design 27 FHe re 12 Final Drop Platen Ds E 27 Figure 13 Interlocking en aaa kaki sl oi ak a EE ak BANG a EN E AGA e a ga Kaga ANK ga a kk ma ka EN ge a aga KANE 28 Howe EAR EE 35 Figure 15 Full Tower Assembly Drawing aaa REER ga aT aha ay ROTH ea r ROAR OT ETid 36 Figure 16 TOW CFB Susana Gen
19. ch test in an attempt to reduce friction Despite the grease this assembly still created large amounts of friction and caused the mass to slow from its theoretical maximum velocity Additionally the complexity and number of struts led to issues with rigidity required maintenance between each test to retighten all the connections This projects conceptual design will focus on reducing friction increasing rigidity by simplifying the drop platen It is hoped that this will increase accuracy of data and reduce the time between tests 15 3 Design Process The evolution of this project s design was not a single step process and went through several major design iterations all designs will be introduced in this section and then elaborated upon 3 1 Important Design Decisions and Tower Parameters The following are important initial design decisions based on ASTM standards simple calculations specifications of commercial drop towers and discussions with experts Dimensioning Dimensions of the base guide rail spacing and drop platen were determined based upon suggestions found in relevant ASTM standards as well as practical limitations The base was sized to fit through doorways for ease of transportation which constrained the dimensions of other components Maximum drop weight of 10 kg and reaction mass of 500 kg According to ASTM D1596 the reaction mass defined as the mass consisting of the impact surface and any other rigidly attached
20. de the box there are also two steel flat stock runners that serve dual purpose as added strength as well as making the base heavier The interior of the box is filled with concrete and scrap metal additives to bring the weight up The dimensions of the box have been changed one final time to now be 33 in X 30 in X 6 in This allows for the purchase of a more standard size steel plate for the top while still allowing the tower to fit through doors The dock bumper feet were replaced by urethane caster wheels to facilitate transportation The urethane caster would not be able to handle the impact of repeated tests nor would it dampen the impact to protect the floor of the lab To counteract this problem as well as lock the drop tower in place set screws with rubber feet were added to the corners of the base The casters were recessed into the base to reduce the distance the set screws have to travel Additionally the winch used to raise the drop platen was moved outside the Plexiglas casing to make it easier to access Lastly to add to the overall weight as well as add more strength to the base two more steel runners were added bringing the total up to four 22 Figure 7 Final Base Design This final base design fits all the design parameters laid out for this project It will be relatively easy to transport and with the concrete and scrap additives will weigh 850 Ibs The steel top also provides a convenient and relatively easy place to sec
21. f b Arr SAN gyw ka LES TITLE Latch Mechanism Platen SHE Diw Ho A latch mechanism Worcester Dote dmi mete SCALE 1 5 WEIGHT A Al SHEET OF az ukk Ea bo EA book Gulch Eslaecth book an ke SECHER EN Figure 29 Quick Release Mechanism Assembly 50 Wo cave Fol peechore Toe Latch Mech anem Asse mb hy cht EE HU TN Caten asembiy ECAI II FEF GFP IGFI 1 LHLES OTHE pwu E PECIFED Ha E DAE Worcester Polytechnic Institute OME DE AREH NGC nE DHAWAH SE 3 25 20 15 IOI ERA GES TITLE AHC AF MACH DEA EE CHE FACE DEC KAL DS EMC AFF Poet ETT RNG ay Halt Inch Im pactor HIEFFREICEGMEIFO DA FEGFR MART A K CEHMRDENTLAL DOT ER AHO FER ASAL TI as I HE IHHT RA DH ECO AE D H ln E AAA ERLA STE DWG NO REY FE EF COOP MT HAA E HERE E DRAM KEZ E IME SOIE PROPERTY GL Haln Carnan eel a we PEPRODUCION H FARI CF AS WADI E HHEN Lo A Inmpac tor PROHENED AFFI CANGH pG HOT SCALE DRAM IHC SCALE 1 1 WEIGHT 0 32 SHEET 1 OF 1 COMES lt PEER GAERA TY hina EN ERES AMT E NAH We IH T nE RI EN FE RESO GL MERI ATY USED Y 4 3 Figure 30 Half Inch Penetrator 51 eB os sa La cel 5 EES GI HERE SPECIHED HAE DALE ae DRS N SWE Tyne 2016 DAE HENNE ARE H IZ MES IGOR RA LC ES TITLE CHECLED ANG AR ACH Z DO Gut PLACE DEC M r 05 EHC APPR gt FIAC E DEC ynu BOUS wah APRE 3 4 Inch Impa ctor LH TTTFET Cro H MP GA PEO FEIL AEN AMD COMO LR IAL r a
22. f sizes ranging from 4X4 in up to 10X10 in The team worked to expand these ideas into a complete design by researching common aerospace materials commercially available drop towers as well as relevant ASTM standards for impact testing This report summarizes the background research performed the design process and the conclusions and recommendations for future work 2 Background Research 2 1 Introduction to types of Drop Tests Since 1898 ASTM international formerly American Society for Testing and Materials has been developing globally recognized voluntary consensus standards for a variety of different processes in an effort to improve product quality enhance safety facilitate market access and trade and build consumer confidence 1 Over the years standards have been developed for many different areas including impact tests using drop towers These standards explore different testing setups for various applications such as football helmets shoes and fencing surfaces as well as many other materials Within the world of impact tests there are two main designations based on setup the Charpy lzod Impact Tests and the Gardner Impact Test In Charpy lzod Impact Tests the dropping mechanism consists of a weighted pendulum which is brought to a pre determined height and dropped The striker at the end of the pendulum swings towards a sample to break it and the energy absorbed by the sample is measured In the Charpy Impact test
23. four guide rails were now arranged in a square pattern requiring the redesign of the drop platen To do this two additional guide arms were added perpendicular to the existing structure resulting in a design resembling a plus sign In order to reduce stress concentrators a radius was added to the inner joint A collar with a set screw was added to Figure 12 Final Drop Platen Design 27 the underside of the drop platen to allow for easy transition between differently sized penetrators On the top surface of the drop platen a rod was added to allow for the use of interlocking test weights to change the total drop mass At the top of the rod there is a pin to allow for the quick release to pick up the drop platen and bring it to the required drop height Figure 13 Interlocking Test Weights 3 6 Quick Release Design To allow for safe and simple operation of the drop tower a quick release latch was needed There are many types of quick release systems commercially available however most of them are expensive and almost none are designed for vertical loading It became necessary to design a new quick release that would handle vertical loads safely The design choices were narrowed down to the spring loaded hook assembly pictured below The hook will slide down on a separate carriage and pick up the drop platen The carriage will carry the 28 platen to the desired drop height A pull cord can then be attached and used to trigger
24. hanged was the base which was resized to accommodate the average door frame around campus since the tower would eventually need to be transported The base was also changed from a solid block of concrete to a box made of steel plate filled with concrete for additional weight Using the concrete cuts down on cost and the steel makes the structure of the tower easier to mount It was also suggested that the guide rails and drop platen design be rethought to prevent the drop platen hitching The original design of the sample mounting area was deemed too difficult to manufacture as well and new designs were developed to simplify fabrication and increase sturdiness Finally the top plate was replaced with a structure made from aluminum x bar extrusions for easier manufacture reduced cost and streamlined integration into the final structure 3 3 Base Design The design for the base of the drop tower underwent several iterations before being finalized The rest of the tower is designed and dimensioned off the base making it a critical piece in the design ASTM standard D 1596 requires that the reaction mass be 50 times greater than the mass of the drop platen In order to comply with this standard the tower is designed to have a base weighing at least 18 385 6 kg 850lbs concentrating the majority of the weight in the base makes the tower more stable The base must also be able to fit through doorways and be transported between different labs and
25. height all of which contribute to impact energy High energy towers can generate up to 100KJ of impact energy and are used to test high strength materials The energy range and size of these towers are well beyond the scope of test materials used in the project their parameters were not incorporated into the initial design 11 Drop weight kg E 37 5 Machine weight kg Test area dimensions m 0 49 x 0 45 x 0 565 0 7 x 0 72 x 0 55 Not specified Overall dimensions m 0 985 x 0 61 x 2 62 1 015 x 0 866 x 2 7 1x0 6x 2 6 Specimens note Suitable for tensile Versatile Can test from For plastic testing impact tests on plates composites to finished and Charpy tests products Table 1 Low to Medium Energy Drop Towers 12 Zwick Roell P550 Imatek IM10T 20 Imatek IM1 P Energy J 340 550 2 5 588 24 118 Impact velocity m s Up to 4 4 1 6 26 2 2 4 85 Drop height m 0 05 2 0 25 1 2 Drop weight kg 34 56 8 30 10 Machine weigh kg 2800 2800 800 Test area dimensions m 0 05 x 0 13 x 0 019 0 7 x 0 72 x 0 55 Not specified Overall dimensions m 1 36 x 0 84 x 2 7 1 42 x 0 76 x 4 5 1 x 0 8 x 3 0 Specimens note Used for composite plastic plaque and film testing Table 2 Medium Impact Energy Drop Towers The initial design for this project was based on the energy range of the Imatek IM1 P which is mainly used for testing composite and plastic plaques It should be noted that these comme
26. ht to the drop platen aligning the space of the interlocking test weights with the drop platen rod Close the Plexiglas door Unlock the winch Lower the quick release carriage until the hook picks up the pin on top of the drop platen Raise the carriage along with the drop platen to the top of the guide rails Lock the winch to prevent the weight from falling Open the Plexiglas door Insert the cut PVC pipes onto the rails Unlock the winch and gently lower the drop platen so that it rests on the PVC pipes Lock the winch again Unscrew the wing nuts on the t bolts fastening the test platforms Slide and adjust the inner edge of the indentation on which the sample will rest of one platform to the corresponding sample size indicated by demarcations along the grooved track Screw the wing nut and fasten the t bolts to hold the platform in place Place one side of the sample on this fixed platform and clamp the sample down using the toggle clamp Adjust and fasten the remaining three platforms so that the sample rests clamped on the four platforms The four sides of the sample should align with its size demarcation Make sure there is no debris in the test chamber Remove the PVC pipes from the guide rails Unlock the winch Lower the drop platen to the desired drop height Lock the winch Close the Plexiglas door Double check the data acquisition system When ready pull the quick release cord The drop platen will be released and the impacto
27. nnot be easily calculated Based on energy considerations it can be shown that mgh F where 6 is the deflection caused by the impact force F Using Newton s laws it can be stated that F MAmax At the impact site assuming that all gravitational potential energy is transferred into kinetic energy the equation can be simplified and solved for acceleration 30 yp 2 Amax 95 Solving for is an altogether more difficult task One empirical eguation for the deflection caused by a concentrated force applied at the center of a square plate that has been clamped on all four sides is presented below 6 0 061 EG Kerg Et3 In this case A is the area of the test sample E is the Young s modulus of the sample material and t is the thickness of the sample Using this equation in conjunction with the equation for ama a reasonable estimate for the acceleration produced by the created impacts can be produced ghEt max 19 061mA This is a rough estimate but should provide a baseline acceleration to work from when selecting the proper accelerometer The table below shows some typical aerospace materials and lists their Young s moduli maximum strain before breaking and predicted amax 31 Young s Modulus GPa kall as Amax 8 Table 3 Sample Materials and Predicted Peak Acceleration Carbon Fiber BMI Carbon Fiber Epoxy Selecting appropriate strain gauges for testing is a much less involved task than
28. other conditions faced these parts must be expertly engineered meticulously manufactured and made from high quality materials To meet the stringent performance and safety demands of the aerospace industry new materials are constantly being developed A thorough knowledge of the mechanical properties of these new materials is necessary to predict their behavior when they are used for their intended purpose There are numerous tests that can be performed to determine properties such as hardness yield strength and energy absorption The most common method for testing energy absorption is by conducting impact tests Drop towers have been developed for reliable repeatable impact tests There are several drop towers commercially available however these models are very expensive and in many cases are unsuitable for aerospace materials testing based upon their range of drop energy WPI currently has two drop towers in the civil engineering labs however neither is suitable for aerospace materials use Both towers are used for testing structural components in civil engineering applications This project focuses on designing a cost effective and reliable drop tower tailored specifically for aerospace applications The initial parameters and goals for this design were developed by the project team Completion of this project required the delivery of a conceptual design of a guided drop tower with a variable impact mass capable of testing samples o
29. r will fall onto the mounted sample Obtain data from the data acquisition system 64 12 Repeat steps 2 to 4 13 Unscrew the wing nuts of two drop platforms closest to the Plexiglas door Unclamp the sample on the two sides Slide the platforms out Unclamp the sample on the other two sides Remove the sample 14 A If conducting further tests using the same drop weights Simply repeat steps 5 to 13 B C If conducting further tests using different drop weights Return the drop platen and the quick release to their starting positions before changing weights Remove the PVC pipes close the Plexiglas door gently lower the drop platen until it rests on the flange mounts pull and hold the release chord raise the carriage to the top of the guide rails and lock the winch this may require an additional operator to hold the cord until the hook clears the drop platen pin Then repeat the process from step 1 to 13 If not conducting any further tests Return the drop platen and the quick release carriage to their starting positions see section B above Then remove the weights clean up the test chamber and close the Plexiglas door 65 Appendix D Quick Release Latch Mechanism Diagram 66 67 68 69
30. rcially available towers have built in velocity and drop height simulation systems to produce a larger range of impact energy In order to compensate for lack of such systems the initial design includes a drop height greater than that of IM1 P The resultant ideal velocity and impact energy will be discussed in section 3 8 13 2 4 Civil Lab Drop Towers WPI currently has two drop towers located in the Civil Engineering department One of them is a commercial tower produced by Instron and the other is a tower designed and built by a previous Civil Engineering MQP team These towers are designed to be used for testing Civil Engineering structural components and are unsuitable for testing aerospace materials The project team also spoke with technicians in the lab and received feedback on how to optimize drop tower functionality based on their experience Their feedback can be summarized as the following e Reduce friction to achieve closer to ideal velocity e Design simplified drop platen e Create more rigid drop platen and impact surface The drop tower built by the previous MQP as well as a close up of the drop platen used are pictured below in figures 1 and 2 Figure 1 Previous MQP Drop Tower 14 Figure 2 Close View of Drop Platen As seen in fig 2 the drop platen used is a very complex design which was developed separately from the main structure It is clamped around the four support columns which were greased before ea
31. reduce friction to a minimum including the use of linear bearings on polished guide rails Four guide rails with ball bearings The tower will have four guide rails as opposed to two providing stability while reducing the chance for the drop platen to hitch Linear ball bearings will also be used where the drop platen comes in contact with the guide rails to reduce friction Depending on how the bearings are clamped the rolling resistance of the bearings can be negligible F Cry N Where C is the coefficient of rolling friction and N is the normal force Typical values for rolling resistance coefficient can vary from between 0 001 to 0 0024 for railroad steel wheel and steel rail to between 0 3 for an ordinary car tire on sand 17 After these major decisions were made the first incarnation of the CAD model was created beginning with the drop platen and the base Included in the initial design were two guide rails used to guide a drop platen which rode on linear bearings a sample mounting system which instituted an adjustment system featuring guided threaded rods and tall platforms a base made entirely of steel and a top plate also made entirely of steel 3 2 CAD Modeling The original design concept would go through major changes following the group s meeting with a manufacturing expert Changes were made to simplify designs decrease fabrication time reduce costs and better overall performance The first piece of the design c
32. se carriage and drop platen 5 Do not leave objects inside the chamber during operation 6 Do not use impactor to strike non deformable objects 7 Frequently check the lifting cable for damage 8 Only add or remove drop weights when both the quick release carriage and the drop platen are in their starting positions see Operation below 62 Specifications Impact Velocity 5 42 m s Impact energy 146 9 Joules Inner guide rail clearance 0 2476 meters 9 748 inches Future teams should include a table of actual impact energy produced for different settings of drop weights and heights when the tower has been built and tested Preparing test site When choosing where to place the tower keep in mind that there should be enough space to operate the winch The feet mounts eliminate the need for the tower to be bolted to the floor or use of shock absorbing surface Still the impact will shake the surrounding area the tower should be placed away from delicate instruments and walls For accurate test results make sure that the floor is level Operation from starting position 63 The starting position of the quick release carriage should always be either the drop height used in a previous test or at the top of the guide rails with the winch locked The starting position of the drop platen is at the bottom resting on the flange mounts Close the Plexiglas door at the end of testing 1 10 11 Attached desired weig
33. t ASTM standards 2 2 ASTM Standards The first relevant standard explored was ASTM D1596 Standard test Method for Dynamic Shock Cushioning Characteristics of Packaging Material The similarity of this standard to the current design problem allowed for many important design characteristics to be determined 3 e The reaction mass or the entirety of the structure not including the drop platen must be at least fifty times the mass of the drop platen so that less than two percent of the impact energy is absorbed by the structure instead of the sample e The use of three test specimens per material and proper conditioning of materials is also stressed in the standard The source material should be tested at various parameters such as temperature humidity thickness etc in order to obtain a more complete analysis of its properties D3763 Standard Test Method for High Speed Puncture Properties of Plastics Using Load and Displacement Sensors is also relevant This standard helps specify a baseline velocity of the drop platen at impact that allows the definition of the maximum drop height 4 F429 Standard Test Method for Shock Attenuation Characteristics of Protective Headgear for Football is another ASTM standard involving Gardner type drop tests that was scrutinized during the literature research While the application is very different from the scope of this project the standard provides new knowledge on sample choice and conditioning Before
34. that for selecting accelerometers Looking at table 3 it can be observed that the range of ema stretches from 0 76 to 16 3 There are commercial models available capable of measuring strains from 0 20 and one of these will be selected at a resistance of 1200 to be compatible with the Wheatstone bridge assembly that is currently available Further selection criteria will be size cost and availability 32 5 Conclusions and Recommendations for Future Work The final design focuses on optimizing the functionality and safety of the drop tower while keeping the total cost as low as possible This means that the final design does not include advanced functions available in expensive commercial drop towers such as a pneumatic brake system and a velocity augmentation system to simulate higher drops Further improvements for future work may include the design of these systems the brake system can help prevent the impactor from striking the test specimen twice in the event that it bounces and the velocity and height adjustment allows for a wider range of impact energy Also not included in the final design is a finalized data acquisition system which was initially to be incorporated when the tower was to be built Future project teams may explore the best options for data acquisition including a refined estimate for the G force loading on the accelerometers generated by impact This will require actual impact test on all available ranges of impact energy
35. the actual testing three initial dry 10 runs of the tower should be performed to check the functionality of the instruments Then after the actual tests three more dry runs should be performed to ensure that the instrumentation functioned properly during testing and that the collected data is reliable Moreover F429 requires that each sample be conditioned for a minimum of four hours before testing and that the test be conducted within five minutes upon removal from the conditioning environment to limit the amount of un conditioning within the sample For every five minutes out of the conditioning environment the sample should be placed back in the conditioning environment for fifteen minutes to reacclimatize itself to the desired conditions These propositions ensure that all data acquisition is working optimally and that testing conditions remain consistent to reduce the amount of error 5 2 3 Commercially Available Drop Towers There are many commercially available towers on the market One of the purposes of this project is to design a more cost effective drop tower The major brands that produce drop towers are Instron Imatek and Zwick Roell These brands offer a wide range of towers with different energy ranges for different types of materials Medium energy towers used for testing aerospace materials were referenced when making initial design choices Primarily the parameters investigated were impact velocity drop weight and drop
36. the sample is mounted horizontally with either a U notch or a V notch oriented away from the striker providing reliable collision data 2 Whereas the Izod Impact test orients the sample vertically with the notch facing the striker on the pendulum evaluating the quality and hardness of the materials Both the Charpy and Izod tests are limited to non compound materials due to their inconsistent failure modes 2 The second major type of drop test and the one that is most similar to the purpose designated for this project is the Gardner Impact test This type of impact drop test is characterized by the vertical dropping of a variable mass impactor striking a sample at the bottom The energy of the impact is determined as a function of the drop height and drop mass In this form of drop test the sample can vary in size shape and orientation ranging from the rubber used in shoes to the plastic used in football helmets The test can be conducted for normal or oblique impacts and in some instances the test specimen itself can be dropped In these tests the energy absorption of the sample is measured by calculating the area under the stress strain curve The force of impact on the specimen can also be determined using accelerometer data and the drop mass 2 While both subsets of impact tests have wide use in the manufacturing and processing world the current project focuses solely on Gardner type impact tests The next section describes relevan
37. the vertical risers While concrete is incredibly strong in compression it is poor when a tensile or bending load is applied Even small non axial forces applied to the tube sleeves could cause the concrete to crack compromising the structure of 20 the tower as a whole Additionally mounting the dock bumper feet would be nearly impossible due to the size and mass of the slab Figure 5 Box filled with concrete A hybrid design was developed for the third iteration To provide support to the concrete a thinner steel plate was placed on top of the concrete slab This cut down on cost from the first iteration and reduced the load on the concrete from the second iteration It also added an easier place to anchor the other components on the top of the base This still left the issue of mounting the dock bumpers below the concrete as well as issues of concrete cracking during transport Creating the frame for the concrete mold and attaching the metal sheet over the top still needed to be addressed The dimensions of the base were also changed at this stage to accommodate transportation through doorways and between labs 21 Figure 6 Third Iteration Base Assembly Design The third iteration of the design builds off of the hybrid design As seen in figure 6 design features a more substantial steel box constructed from a 01 m 5 in steel plate and several pieces of 2 m 7 5 in wide flat stock welded to be edges and an open bottom Insi
38. ure 38 Sample Mounting Platform Assembly 59 non seme ET HET Ped da Manm M A o ET h ev wan e C top assembly cet tw mm a Figure 40 Top Assembly Model 60 Appendix B Bill of Materials Plate Mounts Meester a47065765 872 8 er L Bracket Fasteners McMaster ges 185 Jul 666 Acrylic Panels Miete BS60K228 19694 Al 78776 Door Hinges McMaster 70651162 915 l 366 Corner Brackets McMaster 470651177 670 ei 402 Guide Rail Holders McMaster Lopes 3410 4 1364 o PA AAA Mounts McMaster 49361416 26 73 106 92 Pr ai min lim ai au Linear Bearings Linear SSUFB 16 N A n o S 16 TEN ss il tu Guide Rails Linear 16 TEMP N A mot pp 209734 61 Appendix C User Manual User Manual General Safety Precautions Impact testing for materials involves hazards from high impact forces Users must be aware of all moving components of the assembly especially the drop platen and weight raising mechanism Take care when installing or removing a specimen or assemble Warning 1 Keep any part of body out of the path of falling weight and impactor at all times 2 Only one operator should operate inside the test chamber at any given time Also when a person is operating inside the test chamber no other person should operate the winch 3 Perform regular maintenance 4 Keepthe protective Plexiglas door closed at all times during drop and when raising or lowering the quick relea
39. ure the other components of the drop tower 3 4 Sample Mount Design One of the design requirements given to the team at the beginning of the project was the ability to accommodate samples of various sizes This led to a preliminary design including four sample mounts with a height of 5 in that included a 375 in indentation at the top creating a resting area for the sample to sit in The four sample mounts would be adjusted by tightening threaded rods that ran through the center of the vertical face of the mount The threaded rods were further supported by an a frame structure located behind the mount The sample mounts would follow a grooved track on the platform which would include inch demarcations for accurate adjustment Once the sample was seated in the 23 grooves and the mounts were adjusted a clamping mechanism mounted to the top of the platform would hold the sample in place Figure 8 Initial Sample Mounting Kevin Arruda the manufacturing lab correspondent suggested that this original design was unfeasible to manufacture and too unstable to provide accurate measurements He suggested simplifying the mount by bringing it closer to the supporting plate to reduce horizontal motion during impact He also suggested doing away with the threaded rod and a frame completely and securing the sample from underneath originally with a tapped hole in the bottom of the platform and a bolt and then with a t slot bolt going through the bottom
40. y 2014 Available from http enterprise astm org SUBSCRIPTION NewValidateSubscription cgi D1596 HTML Accessed 9 18 2014 4 Subcommittee D20 10 Standard Test Method for High Speed Puncture Properties of Plastics Using Load and Displacement Sensors online July 2010 Available from http enterprise astm org SUBSCRIPTION NewValidateSubscription cgi D3763 HTML Accessed 9 18 2014 5 Subcommittee FO8 52 Standard Specification for Shock Attenuation Properties of Fencing Surfaces PI May 2014 Available from 3 htm D Accessed 9 18 2014 34 Appendix A CAD Drawings Figure 14 Full Tower 35 Ho FART dur BER DESC FIFI H ar nim asia m oly tina SITS al bose ii m oly BEU 06515 Parera nr kan 1 2060 ME 7D SJ 122 SI 2050 T5 Exrmisiar a Des laz Harg AOL ko sr Te R He ae ee pena Som pi maune As nok keen T aan CE en O AE E menn on menn 3 EA pe Hr Poo aure o O lingar Beorlng ang Culas Foi EN P Aiia m oly EA pey HEO HA BE EE We os ees toreros emase Dron Floren laren noo WE mnacrarz TE ln Ham erer Fe nera nor Daor acc arch me paeran uk Fake ia Haar Flore n 3 ar Nod se mo S farcnaseman Aim oly IU LN SEC IO A A SCAIET IF MIT OH D EFE UI E Heat TE A re uw mann Morcester Polytechnic Ietiite HAD HALE EHEDE mir AHC WAN WF fH leit mes lae ann Full Tower 1HE Fir EE MAJ a E AA hl SE T Assembly Lnb LE ALL FE MALL P
Download Pdf Manuals
Related Search