Modeling and characterization of piezoelectric cantilever bending sensor for energy harvesting

The main aim of this work is to enhance the conversion of mechanical energy into electrical energy by using direct piezoelectric effect. Under the assumption of the Euler–Bernoulli Beam Theory, a piezoelectric cantilever bending of 31-effect was developed. The equations of motion for the global system were established by using Hamilton's principle and solved by using the modal decomposition method. It provided the transfer functions model between the inputs (force) and the outputs (voltage) allowing the description of its dynamic behaviour for energy harvesting. The model was implemented by using Matlab software and will be able to integrate with the circuit model of energy storage. The results obtained show a good agreement with the experiments and other previous works. The model and the experiment indicate that the second mode of resonant frequency provides the voltage and the bandwidth much larger than the first mode. While the mass at the free end increases, the voltage obtained by the first mode increases. In contrast, the voltage obtained by the second mode decreases.