Hybrid explicit–implicit topology optimization method for the integrated layout design of compliant mechanisms and actuators

Increasing the working stroke of compliant mechanisms in a limited space has always been an important topic in mechanics. One effective method is to develop a more fundamental design model that considers the multi-physical coupling characteristics of compliant mechanisms and actuators. This paper presents a new method for the integrated design of compliant mechanisms and piezoelectric actuators, which incorporates the projective transformation-based moving morphable components method with the parametric level set method (PMMC-PLS), based on the use of explicit and implicit topology optimization methods to drive the layout evolution of the embedded actuator and host structure, respectively. The extended finite element method (XFEM) is adopted to accurately capture the boundary of the multi-component system, thereby increasing the accuracy of the structural response and sensitivity analysis. To circumvent defacto hinges and thin wall features, a global manufacturability constraint is proposed by applying the minimum length scale control to the host structure and a non-overlap constraint to embedded actuators. Moreover, the output stiffness is considered to enhance the mechanical performance of the mechanism. The effectiveness of the proposed method is verified considering numerical examples.