Explicit topology optimization for piezoelectric energy harvester with ensured connectivity of polarization profile

This paper proposes an explicit topology optimization approach for simultaneous design of both the structure and polarization profile of piezoelectric energy harvesters (PEHs), with particular emphasis on the connectivity of polarization profile. The approach is established under the Moving Morphable Component (MMC) framework. Two independent sets of MMC components are adopted to simultaneously describe the structural topology of the PEH and the polarization profile of the piezoelectric material. Resorting to the explicit geometry description of MMC, the connectivity of the polarization profile related to PEH manufacturability can be addressed in a straightforward manner using graph theory. A novel connectivity constraint is formulated by considering both connected and disconnected graphs. Meanwhile, the proposed approach is applicable to both subtractive and additive manufacturing strategies under different manufacturing processes. Some numerical examples are provided for cantilever-type PEH. The results demonstrate the effectiveness of the proposed approach in improving energy harvesting efficiency and the connectivity control of the polarization profile for PEH.