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

In addition to the design of piezocomposite? material, discussed by Silva c t al. [1] another important. issue is the design of the piezoelectric trans ducer. This paper introduces this issue by discussing the design of low-fre quency flextensional piezoelectric actuators. They consist of a piezocerami c (or a stack of piezoceramics) connected to a flexible mechanical structur e that converts and amplifies the output displacement of the piezoceramic. The actuator performance depends on the distribution of stiffness and flexi bility in the coupling structure domain, which is related to the coupling: structure topology. The design of the coupling: structure can be achieved b y using topology optimization. By designing: other types of coupling struct ures connected to the piezoceramic. we fall obtain other types of flextensi onal actuators that produce high output displacements or forces in differen t directions, according: to a specific application. Therefore. in this paper, we propose a method for designing flextensional a ctuators by applying topology optimization technique based on the homogeniz ation design method developed by Bendsoe and Kikuchi [2]. It consists of fi nding the optimal material distribution in a perforated structure with infi nite microscale voids. The microscale voids are defined in each finite element subdomain by two di mensions 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 spec ified direction. Only static and low-frequency applications are considered. Although the method introduced is general and can Le applied to the design of three-dimensional (3D) transducers, the examples presented herein are l imited to two-dimensional (2D) models due to lower computational cost. Diff erent types of actuators for different applications call be obtained.