Topology optimization design for two- material micro compliant mechanism with stress constraint

In this paper, the topology optimization design of two material micro compliant mechanism that allows for treating local stress constraint is investigated. A mathematical model is constructed in which the mechanical advantage of the mechanism is posed as objective function while displacement constraint, material constraint and stress constraint are considered simultaneously. The element free Galerkin (EFG) method based on the moving least squares (MLS) approximation is used as a tool for numerical analysis and the thickness of each material phase at the gauss point in the integration cells is taken as design variable, which well describes the local characteristic of the mechanism and improves the computing precision. The topological design of compliant mechanism is then solved as a problem of material distribution using SIMP model with sensitivity filtering technique. The solution of this problem is obtained by using the method of moving asymptotes (MMA). The effectiveness of the mechanism is verified by a numerical example for design of a micro gripper mechanism.