Multiphysics Finite Element Analysis of a ZnO Chevron Piezoelectric Cantilever for Raindrop Impact Sensing and Energy Harvesting

This paper presents a thorough Multiphysics finite element analysis (FEA) of a proposed chevron-shaped zinc oxide (ZnO) piezoelectric cantilever designed for dual-function raindrop impact sensing and micro-energy harvesting. The proposed sensor involves a ZnO piezoelectric top layer (2 µm), an aluminum (Al) electrode (1 µm), and a flexible polyethylene terephthalate (PET) substrate (50 µm), forming a robust and highly sensitive structure. The chevron configuration improves strain localization at the apex, thereby improving mechanical-to-electrical energy conversion efficiency. Coupled electromechanical simulations disclose a maximum von Mises stress of 1.8×10⁸ Pa concentrated near the apex, resulting in a tip displacement of 0.9 nm. The ZnO layer produce an open circuit voltage of approximately 150 mV under a 100 µN impact load, corresponding to a voltage sensitivity of 1530 V/N — meaningfully higher than that of conventional Si/SiO₂ cantilevers. These results prove strong electromechanical coupling and high energy conversion efficiency. The novelty lies in integrating a chevron-based multilayer ZnO/Al/PET structure for simultaneous raindrop sensing and self -powered operation. The proposed sensor is low-cost, strong MEMS architecture for autonomous environmental monitoring and precision agriculture.