Compliant Mechanisms: Memory Lane, the Journey, and the Exciting Road Ahead Ashok Midha

1. Council of Graduate Students (CGS) Ignite Rolla: Breaking Barriers Compliant Mechanisms:Memory Lane, the Journey, andthe Exciting Road AheadAshok Midha

2. Dimitry Grabbe (1928-2011) • Director of Research & Technology (Retired); AMP, Inc. • Integral part of US space exploration • 500 US and foreign patents covering machine design, semiconductor packaging, electronics assembly, optoelectronic connector design, printed circuit board technology • Founded Maine Research Corporation (Apollo missions) • AMP Lifetime Achievement Award • ASME Leonardo da Vinci Award • IEEE Components, Packaging, and Manufacturing Technology Award

3. The Pursuit of Compliant Mechanisms The First Sparks that ignited …

4. AMP Crimping Mechanisms • Two Alternative Versions of Compliant Crimping Mechanisms Designed by AMP Incorporated

5. A Compliant Crimping Mechanism and its Rigid-Body Counterpart

6. Compliant Mechanisms (1982)

8. AMP Chip Carrier Extractor • A Compliant Chip Carrier Extracting Device Designed by AMP Incorporated

9. Compliant Mechanisms Defined • “… elastic or flexible mechanisms are necessarily those that undergo elastic deformations. Their response may or may not be vibratory. In this context, a high-speed mechanism may be regarded as elastic or flexible. … The Webster’s definition of the word compliant, on the other hand, is “ready or disposed to comply: SUBMISSIVE.” Midha, A., Ed. Ch. 9, “Elastic Mechanisms,” Modern Kinematics: Developments in the Last Forty Years, (Ed.: A. G. Erdman), John Wiley & Sons, Inc., New York, New York, 1993, pp. 369-449.

10. Opportunity Envisioned … • “… time has arrived for more challenging uses for thermoplastic materials in load-bearing applications.” He cited as advantages weight reduction, ease of fabrication of complex shapes, and cost reduction resulting from function integration. “Lack of development of the design technology was currently a barrier in their application.” He foresaw such developments as new opportunities for engineering science.” Stokes, V. K, “Thermoplastics in Load-Bearing Applications: New Opportunities for Engineering Science,” Visiting Fellow Presentation, School of Chemical Engineering, Purdue University, November 1987.

11. The Initial Proposal … • NSF proposal: Development of a Methodology for Compliant Mechanisms Design, 1989 • Identification of necessary kinematic properties and definitions • Categorization of mechanism synthesis types, both structurally as well as by virtue of their intended function • Development of efficient computational design methods • Application and computer simulation • Validation through prototyping

12. An Accelerated Pavement Testing Machine An Early Stimulant

13. Modified Single-Input Port and Multiple-Output Port Mechanism

14. A Constant-Force Mechanism Model

15. Output of Constant-Force Mechanism for Five Cycles of Displacement

16. Schematic of Pavement Testing Machine

17. Accelerated Pavement TestingFacility at Purdue

18. Force vs. Deflection for Full-Scale Pavement Testing Machine

19. Thus, Compliant Mechanisms … • Derive some or all of their mobility from deflection of flexible members • May involve large motions due to structural deformations • May be synthesized for prescribed motions, forces or torques, or energy absorption • May provide reduced part count, cost, weight, lubrication, lash, shock and noise; and improved ergonomics, assembly, manufacturability and miniaturization

20. Areas of Applications … • Aerospace (morphing wings) • Automotive (suspension, crashworthiness) • Biomedical devices and prostheses • Micro-electromechanical (MEMS) devices • Robotics and hand tools • Consumer goods (seating, footwear) • Infrastructure (deterministic load distribution)

21. Compliant Mechanisms

22. Compliant Mechanism Applications … • Flex-foot • TROCAR Surgical Tool

25. Compliant MechanismsExample: (a) AMPSTAR Compliant Electrical Connector in (b) Initial and Deformed Positions

26. Compliant MechanismsExample 5: Electrical Contact Design to Produce a Nearly Constant Force vs. Deflection Characteristic

27. Safing Mechanism

28. Research at Brigham Young University • Applications including Origami based designs

29. Commercialization Exploiting advantages of compliant mechanisms in products

30. BYU Spinal Disc

32. Challenges and Excitement Ahead … • Compliant Mechanisms are here to stay, and spreading across disciplines rapidly • Their behavior is less intuitive; a greater understanding must be developed • Continued development of enabling and pragmatic design methodologies • Consumer education and dissemination of information

33. Challenges and Excitement Ahead … • Tremendous knowledge base at work in support • Accelerated buy-in from industrial partners, academic institutions and federal agencies • High-speed applications with unique challenges

34. Challenges and Excitement Ahead … • A large interdisciplinary interest in place, and growing • As other disciplines advance, so does the compliant mechanism technology • Opportunities are endless, limited only by our imagination

35. Conventional Wisdom • Conventional wisdom can be like concrete; it’s good to walk on, and it gets you places fast. But nothing beautiful, rare or worthwhile will grow in it. However, if it is formed to cup a seedling in a nurturing environment, growth is but certain and its fruits are sure to follow. A.M.