Mechanical electrical coupling analysis of a 3D braided composite piezoelectric energy harvester with spring support to expand the frequency domain

In this paper, 3D braided composites are considered for high-performance piezoelectric energy harvester designing, and a 3D braided composite piezoelectric energy harvester (3D BCPEH) is proposed. The advantage of 3D BCPEH is that the natural frequency of the device can be adjusted by adjusting the stiffness of the spring, making the natural frequency of the device close to the vibration frequency of the environment, thereby achieving the best harvesting effect of the energy harvester. During the vibration process, spring support can cushion the impact and stress on the piezoelectric energy harvester, thereby protecting the device from damage and helping to improve the stability and performance of the system. Finite element analysis is used to obtain the elastic modulus, shear modulus, and Poisson’s ratio of 3D braided composites with varying braiding angles. Based on Hamilton’s variational principle, the vibration control equation of the spring supported 3D BCPEH is derived. The effects of spring rate, braiding angle, external excitation acceleration, external load resistance, and structure size on the output response of 3D BCPEH are simulated and analyzed. The validity of the proposed 3D BCPEH with spring support is confirmed by the simulation results.