Design optimization of a twist compliant mechanism with nonlinear stiffness

Yashwanth Tummala, Mary Frecker, Aimy Wissa, James E. Hubbard

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

A contact aided compliant mechanism called twist compliant mechanism is presented in this paper. This mechanism has nonlinear stiffness when it is twisted in both directions along its axis. The inner core of the mechanism is responsible for its flexibility in one twisting direction. The contact surfaces of the cross-members and compliant sectors are responsible for its high stiffness in the opposite direction. A twist compliant mechanism with desired twist angle and stiffness can be designed by choosing the right thickness of its cross-members, thickness of the core and thickness of its sectors. A multi-objective optimization problem with three objective functions is proposed in this paper, and used to design an optimal twist compliant mechanism with desired deflection. The objective functions are to minimize the mass and maximum von Mises stress observed, while minimizing or maximizing the twist angles under specific loading conditions. The multi-objective optimization problem proposed in this paper is solved using an ornithopter flight research platform as a case study, with the goal of using the twist compliant mechanism to achieve passive twisting of the wing during upstroke, while keeping the wing fully extended and rigid during the downstroke. Prototype twist compliant mechanisms have been fabricated using a waterjet cutter and will be tested as part of future work.

Original languageEnglish (US)
Title of host publicationMechanics and Behavior of Active Materials; Structural Health Monitoring; Bioinspired Smart Materials and Systems; Energy Harvesting
PublisherAmerican Society of Mechanical Engineers
ISBN (Print)9780791856048
DOIs
StatePublished - Jan 1 2013
Externally publishedYes
EventASME 2013 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2013 - Snowbird, UT, United States
Duration: Sep 16 2013Sep 18 2013

Publication series

NameASME 2013 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2013
Volume2

Other

OtherASME 2013 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2013
CountryUnited States
CitySnowbird, UT
Period9/16/139/18/13

ASJC Scopus subject areas

  • Artificial Intelligence
  • Civil and Structural Engineering

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