An experimental and theoretical piezoelectric energy harvesting from a simply supported beam with moving mass

Abstract

The feasibility of harvesting electrical energy from mechanical vibration is demonstrated in the thesis. In the technique, energy is harvested from simply supported beam vibration under a moving mass using a thin piezoelectric material.The structure is represented by a basic beam of length L that is supported at both ends and traversed by a moving mass M travelling at a constant velocity v. The Euler-Bernoulli differential equation describes its behaviour. The dynamic analysis of a beam is performed by using three moving masses of (35.61, 65.81, and 79.41) gr each travelling three uniform speeds of (1.6, 2 and 2.4) m/s. A differential equation of the electromechanical system is obtained by transforming the piezoelectric constitutive equation and solved numerically by MATLAB.The results indicate that the numerical and experimental values for the midpoint deflection of the beam and the piezoelectric voltage are very close.Using the COMSOL programme, the proposed approach is checked by comparing results with data obtained by the finite element method (FEM). An experimental setup was also built and constructed to determine the voltage created by the piezoelectric patch and the beam response as a result of the mass travelling along the beam.The results show that the dynamic deflection, piezoelectric voltage, and piezoelectric energy harvesting all increase as the speed and magnitude of the moving mass increase. The harvesting power vs. load resistance curve begins at zero, increases to a maximum value, and then remains almost constant as the resistance is increased further. The optimal length of the piezoelectric patch was obtained to be 0.63 m. When the length of the beam increases, the resonant frequency decreases, and at the same time the harvested energy increases. However, increasing the beam thickness has the opposite effect; whereas raising the beam width does not affect the resonant frequency but decreases energy harvesting.The most essential point here is the need to have correctly built scale models. They can provide a substantial amount of information at a low cost, accommodate a variety of test settings, and aid in the selection and verification of the most effective analytical model to resolve the actual issue.