Nonlinear synthesis of compliant mechanisms with selective compliance

TL;DR

This paper introduces a nonlinear synthesis method for compliant mechanisms that ensures reliable path generation under various loads, including a novel shape-adaptive mechanism, addressing limitations of previous linear approaches.

Contribution

It extends existing load case insensitive synthesis methods to include nonlinearities, enabling the design of more robust, path-generating compliant mechanisms with shape adaptability.

Findings

Successfully synthesized nonlinear path-generating mechanisms

Demonstrated shape-adaptive compliant mechanism design

Validated approach with practical design examples

Abstract

The synthesis of compliant mechanisms (CMs) is frequently achieved through topology optimization. Many synthesis approaches simplify implementation by assuming small distortions, but this limits their practical application since CMs typically undergo large deformations that include geometric and material nonlinearities. CMs designed to generate a desired deformation path at the output points under specific loads are known as path-generating CMs. However, these CMs face significant challenges in topology optimization, resulting in the development of only a few optimization methods. Existing approaches often include only certain load cases in the optimization process. Consequently, if a CM designed this way encounters different load cases in practice, its path-generating behavior cannot be guaranteed. The authors have previously contributed to the development of an approach suitable for synthesizing load case insensitive CMs. This paper extends that approach to account for nonlinearities, enabling the synthesis of path-generating CMs. The effectiveness of this extended approach is demonstrated through appropriate design examples. Additionally, the paper presents, for the first time, a shape-adaptive path-generating CM.