Insights on the crack modeling and effectiveness of piezoelectric energy harvesters

Abstract

A damage model for investigating the performance of cracked piezoelectric vibrational energy harvesters (VEHs) is developed. The crack model adopted does not alter the piezoelectric properties of the lead zirconate titanate patch but modifies the structural stiffness at the crack location following the Griffith’s strain release formulation. Multiple VEH configurations are considered to determine how the performance of various sized piezoelectric patches are impacted by multiple edge cracks. It is demonstrated that thicker piezoelectric patches are more severely impacted by cracks than thinner patches. The number of cracks, proximity of the cracks to the base of the VEH, and crack depth are shown to affect VEH performance. It is shown that severe cracks have a pronounced influence on the stiffness of the energy harvesting system, thus causing a deviation in the resonance region and amplitudes of the damaged system. The increased flexibility of the cracked piezoelectric patches increases the tip deflection and decreases the resonant frequency which can shift the initial optimal resistance to some higher value thus, greatly affecting the efficiency of piezoelectric energy harvesters.