Topology optimization of contact-aided compliant mechanisms for tracing multi-kink paths

TL;DR

This paper introduces a topology optimization method for designing 2D contact-aided compliant mechanisms capable of tracing complex multi-kink paths, incorporating contact modeling and shape optimization techniques.

Contribution

It presents a novel topology optimization framework that integrates contact surfaces, boundary smoothing, and shape descriptors for designing complex compliant mechanisms.

Findings

Successfully designed mechanisms tracing multi-kink paths

Effective incorporation of contact modeling in topology optimization

Demonstrated path accuracy through optimized designs

Abstract

This paper presents a topology optimization approach to design 2D contact-aided compliant mechanisms (CCMs) that can trace the desired output paths with more than one kink while experiencing self and/or external contacts. Such CCMs can be used as mechanical compliant switches. Hexagonal elements are used to parameterize the design domain. Negative circular masks are employed to remove material beneath them and generate rigid contact surfaces. Each mask is assigned five design variables. The first three decide the location and radius of the mask, whereas the last two determine the presence of the contact surface and its radius. To ensure continuity in contacting surfaces' normal, we employ a boundary smoothing scheme. The augmented Lagrange multiplier method is employed to incorporate self and mutual contact. An objective is formulated using the Fourier shape descriptors with the permitted resource constraint. The hill-climber optimization technique is utilized to update the design variables. An in-house code is developed for the entire process. To demonstrate the method's efficacy, a CCM is optimized with a two-kink path. The desired and obtained paths are compared.