1. Loading Apparatus for High Velocity Tissue Rupture Mechanical Engineering Dalhousie University Senior Design Project Winter 2010

2. Group 12 Geoff Beck Ben Breen Ruth Domaratzki Rachael Schwartz

3. SupervisorClient  Dr. Kujath  Mechanical Engineering Dalhousie University  Dr. Lee  Biomedical Engineering Dalhousie University

4. Background Final Design Testing and Performance Design Requirements Budget Future Considerations Presentation Outline

5. Application: Determine the mechanics of high-speed failure for a biological specimen Simulate impact trauma Presently: Dalhousie BME,  max = 10 s -1 Limited by servo-hydraulic actuation method Desired: To overcome current tensile testing limitations. Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions Background

6. Final Design Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

7. Final Design: Grip and Housing Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

8. Contents Background Design Requirements Design Selection Selected Design Budget Future Considerations Conclusions Questions Final Design: Drive Shaft Assembly

9. Final Design: Engagement Pin Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

10. DisengagedEngaged Final Design: Engagement Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

11. Final Design: Engagement Use optical encoder to determine pin position Functions using IR sensor Encoder has one hole located (180º) opposite pin position Able to sense when pin has passed solenoid Ensures the solenoid does not engage pin in a partial contact scenario Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

12. Minimize rotating masses. Encase in polycarbonate shield. No controls in immediate area. Started and Controlled via DAQ. Final Design: Safety Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

13. Final Design: Measurement Systems Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

14. Final Design: Measurement Systems Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

15. Final Design: Measurement Systems Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions Verification of LVDT data included implementing high speed video to determine velocities Flywheel angular velocity was verified comparing the controller output to the strobe frequency

16. Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions Final Design: Measurement Systems

17. Testing and Performance Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions Tested bovine pericardium tissue.

18. Testing and Performance Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

19. Testing and Performance Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

20. Testing and Performance Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

21. Testing and Performance Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions Shadwicke RE. Mechanical Design in Arteries. K Exp. Biol. 202, 3305-3313, 1999.

22. Testing and Performance Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

23. Testing and Performance Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions 1000RPM – 1000fps

24. Testing and Performance Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions 500RPM – 500fps

25. Design Requirements Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions Design RequirementStatus The device should fit on table top with face dimensions 30in x 30in. 23in X 22in Operator able to control extension rate Implemented frequency drive to vary flywheel speed Able to achieve a maximum strain rate of 1000 s -1 Achieved maximum strain rate of 800 s -1 Achieve a maximum of 1ms tension load application to fracture Confirmed 4ms

26. Design Requirements Design RequirementStatus Device should provide measurement of force and displacement with time LVDT and Load Cell incorporated in design. Data processed using DAQ The conditions of the test will be at 100% humidity and 37ºC Client selected implementation of high speed camera over conditions. Used spray bottle to keep sample at conditions. Designed to be safely operated by trained individuals. A shielding component will be incorporated if required Easy to operate. Shielding component was constructed. Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

27. Design Requirements Design RequirementStatus Device should be accompanied by a complete instruction manual Instruction manual supplied to client Device should last five years Robust design; Given client spare critical components Meet all requirements outlined in the MECH DP 2009/2010 handbook On track to meet all requirements Total Design Requirements Met: 7/10 Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

28. MECHANICAL Frame 50.00 Flywheel 40.00 Stainless Steel 173.00 Main Shaft 0.00 Other 536.00 ELECTRICAL Motor 230.00 LVDT & Function Generator 800.00 Solenoid 16.00 Frequency Controller 335.00 Force Transducer 260.00 Other 35.00 TOTAL $2475.00 Budget Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

29. Substitute stainless steel in place of plastic bath Reduce mass of moving parts in an effort to reduce inertia Reduce moment acting on engagement pin Create dedicated circuit boards or shield electrical components to reduce crosstalk Future Considerations Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

30. Constructed a device that in the future will lead to a better understanding of tissue mechanics Satisfied with dynamics and control of device Several design features that our client will continue to refine and develop Gained valuable knowledge and experience Conclusions Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions

31. Special Thanks To: Dr. Marek Kujath Dr. J. Michael Lee Mark, Angus, and Albert Dr. Julio Militzer Dr. Darrel Doman Jon MacDonald Peter Jones Acknowledgements

32. Senior Design Project Team 12 Dalhousie Department of Mechanical Engineering Winter 2010 Questions?

34. Mechanical / Electrical Crosstalk

35. Solenoid Selection and Performance

36. Machine Status: Angular velocity of the flywheel Position of the rotating impact surface (pin) Experimental Variables: Specimen stress Standard strain gauge load cell Specimen displacement Linear Variable Differential Transformer Final Design: Measurement Systems Contents Background Final Design Testing and Performance Design Requirements Budget Future Considerations Conclusions