Shape optimization of non-uniform parametric piezoelectric energy harvester beam

Abstract

This study presents an efficient electromechanical model for the analysis of piezoelectric energy harvesters (PEHs) with varying cross-sectional widths along their length. The model, validated through finite element method (FEM) simulations and experimental data, enables rapid analysis and optimization of PEHs. The Nelder-Mead optimization algorithm was employed to enhance power generation performance across three cross-sectional configurations: rectangular, trapezoidal, and quadratic. Results indicate that optimization significantly improves the power density of conventional cantilever piezoelectric beams, achieving high power outputs without the need for complex structures. Among the configurations, the quadratic PEH demonstrated the highest normalized power (31.31 mW/g²) and safety factor (13.79) in the linear region. Although the trapezoidal PEH showed superior safety under large deformations, the quadratic design achieved the highest peak power (166.9 mW) and peak power density (43.80 mW/cm³) at the maximum base acceleration. The optimized quadratic energy harvester thus represents one of the most effective designs reported in the literature for PEHs.