End cap profile optimization of a piezoelectric Cymbal actuator for quasi-static operation by using a genetic algorithm

This article describes how an extrinsically amplified Cymbal-type piezoelectric actuator is optimized for displacement generation by using genetic algorithms in combination with COMSOL Multiphysics finite element method modeling software. The research was focused on optimizing the shape of the end cap profile in a quasi-static operation scheme in order to keep the number of parameters and calculation times at a reasonable level. In contrast to conventional linear end cap profiles, a genetic algorithm tends to generate more complex shapes and especially a corrugated structure in the vicinity of the output point of force and displacement. Modeling showed that about 26.9% higher displacement could be produced with a complex shape derived by the algorithm compared with a linear end cap profile. Moreover, about the same level of displacement as achieved with a wagon wheel transducer was obtained simply by profile optimization without material removal, which could, however, improve performance even further. The developed genetic algorithm proved to be a feasible tool for complex multi-parameter optimization, utilizable in a wide range of shape and structure optimizations for future electromechanical components.