Structure simulation optimization and test verification of piezoelectric energy harvester device for road

Abstract

The structure of piezoelectric energy harvester device has a significant impact on electromechanical conversion performance, and appropriate structural parameters are the important premise to ensure electromechanical conversion efficiency. In order to design the detailed structures which are more conducive to the electromechanical conversion in the d33 mode, and optimize or enhance the mechanical response of the piezoelectric energy harvesting unit, a finite element model was established to comprehensively analyze the influence of the detailed structures on the electromechanical response of the energy harvesting unit, based on the results, optimal detailed structural parameters are determined, and lateral mechanical environment of the energy harvesting unit is optimized. Finally, the stacked piezoelectric energy harvester device for road is made, and the rationality of optimization is verified by the MTS indoor comparative test. The results show that the protective pad with a fillet size of 3 mm, a thickness of 3 mm and an elastic modulus of 8000∼15000 MPa can effectively avoid edge stress concentration and obtain maximum top compressive stress for the energy harvesting unit, and also ensure durability and electrical output. Compared with the baseplate, the influence of the upper cover plate on electrical output is more significant, and the elastic modulus of the upper cover plate should be less than 2000 MPa, the thickness should be controlled within 8∼10 mm. The potential difference generated by the energy harvesting unit in lateral constraint environment is 40 % lower than that in no lateral constraint. Under load of 0.7 MPa-10 Hz, the terminal voltage of the optimization group is 2.2 times that of the control group, the average output power is 4.9 times, and the power density is 2.7 times, which shows the optimization rationality of detailed structures.