A distributed-parameter electromechanical coupling model for a piezoelectric energy harvester with variable curvature

Enabling technologies for harvesting ambient vibration energy have attracted considerable attention in research communities from different disciplines in the last decades. Among the various devices, straight cantilever-based energy harvesters have been widely investigated from the perspective of designs, modeling, simulation and experiments. In this study, we propose curved piezoelectric energy harvesters (PEHs) with variable curvature to further broaden application scenarios. Within the framework of the Euler-Bernoulli beam theory, we develop a distributed-parameter electromechanical coupling model for a curved segmented unimorph with variable curvature by Hamilton's Principle and solve it using the Rayleigh-Ritz method. The convergence and accuracy of the model are validated by finite element simulation and experiments. Based on the proposed model, we perform a systematic parameter study and discuss the effects of the proof mass, Young's modulus of the substrate, the thickness ratio of the substrate to the total thickness, the curvature of the substrate and the piezo patch on the mechanical and electrical responses of the structures. The theoretical model will help engineers to design and optimize new PEHs and serve as a benchmark solution for future research in this field.