Open Access

ARTICLE

A Multi-Criteria Topology Optimization for Systematic Design of Compliant Mechanisms

Zhen Luo^1,2, Nong Zhang,^1,3

1 School of Electrical, Mechanical and Mechatronic Systems, The University of Technology, Sydney, NSW 2007, Australia
2 State Key Lab. of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian, 116024, China
3 Author to whom all correspondence should be addressed, Tel: +61-2-9514 2662; Fax: +61-2-95142655. E-mail address: nong.zhang@uts.edu.au(Prof. N. Zhang)

Computers, Materials & Continua 2012, 28(1), 27-56. https://doi.org/10.3970/cmc.2012.028.027

Abstract

This paper attempts to present a new multi-criteria topological optimization methodology for the systematic design of compliant micro-mechanisms. Instead of employing only the strain energy (SE) or the functional specifications such as mechanical efficiency (ME), in this study an alternative formulation representing multiple design requirements is included in the optimization to describe the performance of compliant mechanisms. In most conventional designs, SE is used to only measure the design requirement from the point of view of structures, while ME is usually applied to describe the mechanical performance of mechanisms. However, the design of a compliant mechanism is required to comprehensively consider both the structural and mechanical performance quantities. Displacement, material usage and dynamic response are imposed as three external constraints to narrow the searching domain. In doing so, the multi-criteria optimization problem involving the SE and ME can reasonably embody the mechanical structural characteristics of compliant mechanisms. A sequential convex programming, the method of moving asymptotes (MMA), is applied to solve the topological optimization problem, which can not only ensure numerical accuracy but also both the monotonous and non-monotonous structural behaviors. SIMP model (solid isotropic material with penalization) is used to indicate the dependence of elastic modulus upon regularized element densities. Several typical numerical examples are used to demonstrate the effectiveness of the proposed methodology, and the prototype of a resulting mechanism has also been manufactured to validate the design of the compliant mechanism.

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