Topology Optimization of Piezoelectric Plate Energy Harvester Under External In-Plan Force Considering Different Boundary Conditions

In this paper, the goal is to optimize the electrical power of a rectangular piezoelectric plate which is under application of external in-plan force. The most challenging problem for in-plane force is the charge cancellation which is due to combination of tension and compression in different parts of the plate resulted by the external force. To remedy, the topology optimization method is utilized to find the best possible design of the piezoelectric plate to overcome the charge cancellation and produce maximum voltage. To do so, first a detailed two dimensional finite element modelling of the piezoelectric material suitable for topology optimization is presented. Then, the topology optimization method known as solid isotropic material with penalization (SIMP) is extended for the 2D FEM piezoelectric model which is faster than the 3D FEM modelling in case of in-plan force and stress. The performance of the topology optimization is investigated for different boundary conditions in addition to classical cantilever plate with clamped-free boundary condition. Finally, the optimized designs for different boundary conditions are implemented in COMSOL multiphysics platform. The results demonstrate that the optimized design by topology optimization method can produce more voltage in comparison to simple full plate while having less volume of piezoelectric material.