Acoustic energy harvesting using an array of piezoelectric cantilever plates for railways and highways environmental noise

This paper introduces a model of sound energy harvesting that operates at a low frequency of less than 200 Hz. This investigation focuses on the produced outcomes when the vibrations of sound energy are converted into electricity. Sound vibrations are received from outside sources and pass through a piezoelectric barrier (wall) equipped with 4*3 array of energy harvesting elements of lead zirconate titanate (PZT-5H) cantilever plates which are constructed to harvest noise in the form of sound from passing trains and vehicles on roads. This paper covers how sound vibrations change into electrical energy at two sound pressure levels (85 dB and 100 dB for environmental noise of road vehicles and railways, respectively). Furthermore, the effects of changing the pressure level on the generated voltage for the intended model have been studied as well as the effects of increasing the piezoelectric plate number on the voltage generated for the 85 dB pressure level. The simulation is conducted numerically using the Finite Element Method FEM (COMSOL). An analytical model of a literature paper is used and simulated using MATLAB to be compared with the FEM results and found to be completely converged. Afterward, to figure out the relationship between voltage and sound pressure level, an equation is derived analytically. According to simulation results, 15 V and 18.2 V are produced for an incoming acoustic pressure level of 85 dB and 100 dB, respectively. Two models are compared, an array of beams with similar dimensions and a single beam with a volume that equals the dimensions of all array beams; it is observed that the array of beams produced 33.9 % more voltage than a single beam with the same volume. The comparison of the proposed model results with experimental literature results is conducted and exhibited an excellent convergence.