Post on 26-Dec-2015
Loading Apparatus for High Velocity Tissue Rupture
Mechanical EngineeringDalhousie University
Senior Design ProjectWinter 2010
Group 12
Geoff Beck
Ben Breen
Ruth Domaratzki
Rachael Schwartz
Supervisor Client
Dr. Kujath
Mechanical Engineering Dalhousie University
Dr. Lee
Biomedical Engineering Dalhousie University
• Background• Final Design • Testing and Performance • Design Requirements• Budget • Future Considerations
Presentation Outline
Application:
• Determine the mechanics of high-speed failure for a biological specimen
• Simulate impact trauma
Presently:
• Dalhousie BME, emax = 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
Final Design
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
Final Design: Grip and Housing
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
Contents• Background• Design
Requirements• Design Selection• Selected Design• Budget • Future
Considerations• Conclusions• Questions
Final Design: Drive Shaft Assembly
Final Design: Engagement Pin
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
Disengaged Engaged
Final Design: Engagement
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
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 scenarioContents
• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
• 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
Final Design: Measurement Systems
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
Final Design: Measurement Systems
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
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
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
Final Design: Measurement Systems
Testing and Performance
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
• Tested bovine pericardium tissue.
Testing and Performance
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
Testing and Performance
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
Testing and Performance
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
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.
Testing and Performance
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
Testing and Performance
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
1000RPM – 1000fps
Testing and Performance
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
500RPM – 500fps
Design Requirements
Contents• Background• Final Design• Testing and
Performance• Design
Requirements• Budget • Future
Considerations• Conclusions
Design Requirement Status
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
Design Requirements
Design Requirement
Status
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
Design Requirements
Design Requirement
Status
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
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
• 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
• 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
Special Thanks To: Dr. Marek KujathDr. J. Michael LeeMark, Angus, and
Albert Dr. Julio MilitzerDr. Darrel DomanJon MacDonaldPeter Jones
Acknowledgements
Senior Design Project Team 12
Dalhousie Department of Mechanical Engineering
Winter 2010
Questions?
Mechanical / Electrical Crosstalk
Solenoid Selection and Performance
• 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