Numerical Design of Novel piezoelectric generating structure that effectively utilizes the force generated from human motion

One of the clean, freely and widely available sources of piezoelectric energy harvesting is from human induced strain while in motion. Piezoelectric materials are promising for energy harvesting from the force generated by human footsteps, into a useful form of electrical energy. The piezoelectric energy harvesting (PEH) module proposed in the present study consists of a novel mechanical structure with beams and helical compression spring. The mechanical structure and beams are made of SUS304 steel and the beams are glued with PZT 5A disks. The structure is optimized to generate maximum deflection in the beams with the applied force resulted from human walking. The maximum deflection in the beams, results in maximum output voltage generation in the PZT disks. The generated voltage is fed to the load through a full-wave rectifier. The restoring force for the mechanical structure is provided using phosphor bronze helical compression spring. A total of 40 PZT disks are used in the present energy harvesting module. The whole structure is enclosed in a wooden structure. The complete PEH module is numerically simulated in COMSOL 5.4. The optimized PEH module resulted in an output power of 0.64 mW for an applied force of 500 N which is equivalent to one step of human walking.