An Ants-Search Based Method for Optimum Synthesis of Compliant Mechanisms

Abstract

Compliant mechanisms are widely used in the industry and have gained more popularity in the past few decades with the advancements in smart materials and micro-electro mechanical systems (MEMS). Compliant mechanisms offer huge advantages over the classical rigid linkages due to their flexible behavior. Such flexible mechanisms reduce production time and cost especially that they eliminate the need of joints that can get pretty hectic especially at micro level manufacturing and assembly. By avoiding multi-joints in the design and their consequent clearances, a compliant mechanism can offer higher precision over its rigid counterpart. However, these advantages come with a price; compliant mechanisms are more challenging in terms of design and analysis. Many compliant mechanisms are designed to undergo relatively large deflections which in turn impose geometric nonlinearities. In the past, many compliant designs were based on intuition, experience, and trial and error. Later on, many theories developed to assist in designing and analyzing compliant mechanisms before proceeding with the manufacturing phase. This paper covers topology optimization of compliant structures using beam elements. The swarm intelligence technique known as Ant Search (AS) is used to find the optimum design that satisfies the required mechanism performance. A case study that involves the topology design of a miniature compliant displacement amplifier is presented and results are compared with the finite element solver ANSYS. The optimized topology mechanism produced a much larger amplification ratio as compared to that * Address all correspondence to this author presented in literature. Results produced show the high potential of swarm intelligence and AS in particular at solving multidisciplinary optimization problems that should not be limited to designs that involve physical paths. NOMENCLATUREAS Ant search PRBM Pseudo-rigid-body model SE Strain energy MSE Mutual strain energy l Beam element length b In-plane width t Out-of plane thickness A Beam element cross-sectional area ν Poisson ratio E Young's modulus δ out Output displacement