Analysis of tension-tunable clamped–clamped piezoelectric beams for harvesting energy from wind and vibration

This article presents a nonlinear structural modeling framework to analyze a tensioned doubly clamped energy harvesting device. The device is investigated for energy harvesting under base excitation loading, where the structure undergoes bending motion and aerodynamic loading, where the structure undergoes combined bending–torsion motion. Transfer-matrix method for analyzing torsional motion is modified to include the effects of applied axial preload tension. The tension-modulated mode shapes and natural frequencies of the structure, obtained using transfer-matrix method, are found to be in good agreement with the results obtained using a commercially available Finite Element software. Under base excitation loading, it is shown that the effects of tension on electromechanical coupling and stiffness create competing influences on the power efficiency of the system. For aerodynamic loading, increasing preload tension increases the cut-in wind speed of the device. However, beyond the cut-in wind speed, with proper selection of the preload tension, the tensioned structure can produce an order of magnitude more power than the untensioned case at the same flow speed.