Topology synthesis of a 3-kink contact-aided compliant switch

TL;DR

This paper presents a topology synthesis method for designing 2D contact-aided compliant mechanisms with complex output paths featuring multiple kinks, using various external contact surfaces and stochastic optimization.

Contribution

It introduces a novel synthesis approach combining multiple contact surface types and a network-based topology generation for complex compliant mechanisms.

Findings

Successfully designed a 3-kink contact-aided switch

Demonstrated effectiveness with friction and wear considerations

Utilized stochastic search for topology optimization

Abstract

A topology synthesis approach to design 2D Contact-aided Compliant Mechanisms (CCMs) to trace output paths with three or more kinks is presented. Synthesis process uses three different types of external, rigid contact surfaces: circular, elliptical and rectangular: which in combination, offer intricate local curvatures that CCMs can benefit from, to deliver desired, complex output characteristics. A network of line elements is employed to generate topologies. A set of circular subregions is laid over this network, and external contact surfaces are generated within each subregion. Both, discrete and continuous design variables are employed: the former set controls the CCM topology, appearance and type of external contact surfaces, whereas the latter set governs shapes and sizes of the CCM constituents, and sizes of contact surfaces. All contact types are permitted with contact modeling made significantly easier through identification of outer and inner loops. Line topologies are fleshed out via a user-defined number of quadrilateral elements along lateral and longitudinal directions. Candidate CCM designs are carefully preprocessed before analysis via a commercial software and evolution using a stochastic search. The process is exemplified via a contact-aided, 3-kink mechanical switch which is thoroughly analysed in presence of friction and wear.