Design and analysis of a Bioinspired auxetic metabeams energy harvester

This work investigates the effects of bioinspired auxetic meta-structures on bimorph piezoelectric cantilever energy harvester devices. Auxetic materials, characterized by a negative Poisson’s ratio, produce uniform stresses under mechanical loading, making them ideal for enhancing power generation in energy harvesters. Two bioinspired auxetic energy harvesters (BAEH), the full-sized auxetic (BAEH1) and the patch auxetic (BAEH2) piezoelectric energy harvesting devices with a tip mass, are presented for the application of transverse loads. The piezoelectric layers are assumed to be wired in parallel configurations. The objective is to achieve the optimum design solutions for auxetic systems that produce more output power than traditional energy harvesting systems. The Timoshenko beam model is developed to derive the coupled electromechanical equations of the auxetic harvesters, and an exact solution is employed to evaluate its electrical performance. 3D finite element (FE) models are also constructed to validate the analytical model, with convergence and comparison studies confirming its stability and accuracy. A parametric study and stress analysis explore how design parameters influence power harvesting. Under identical operating conditions, the bioinspired auxetic energy harvesters generate an output power nearly 70% greater than traditional harvesters. These findings emphasize the potential of auxetic structures and multifunctional composites in enhancing vibration-based energy harvesting technologies and various engineering applications.