Design of piezocomposite materials and piezoelectric transducers using topology optimization—Part II

Summary

In addition to the design of piezocomposite material, discussed by Silvaeet al. [1], another important issue is the design of the piezoelectric transducer. This paper introduces this issue by discussing the design of lowfrequency flextensional piezoelectric actuators. They consist of a piezoceramic (or a stack of piezoceramics) connected to a flexible mechanical structure that converts and amplifies the output displacement of the piezoceramic. The actuator performance depends on the distribution of stiffness and flexibility in the coupling structure domain, which is related to the coupling structure topology. The design of the coupling structure can be achieved by using topology optimization. By designing other types of coupling structures connected to the piezoceramic, we can obtain other types of flextensional actuators that produce high output displacements or forces in different directions, according to a specific application. Theorefore, in this paper, we propose a method for designing flextensional actuators by applying topology optimization technique based on the homogenization design method developed by Bendsøe and Kikuchi [2]. It consists of finding the optimal material distribution in a perforated structure with infinite microscale voids. The microscale voids are defined in each finite element subdomain by two dimensions and one orientation which are the design variables in the problem. The problem is posed as the design of a flexible structure coupled to the piezoceramic that maximizes the output displacement (or force) in some specified direction. Only static and low-frequency applications are considered. Although the method introduced is general and can be applied to the design of three-dimensional (3D) transducers, the examples presented herein are limited to two-dimensional (2D) models due to lower computational cost. Different types of actuators for different applications can be obtained.