Energy Harvesting from Clustered Piezoelectric Beams for Aircraft Health Monitoring Systems

Energy harvesting has emerged as a promising solution for powering aircraft structural health monitoring (SHM) systems by exploiting ambient vibration energy. This work presents a novel clustered piezoelectric energy harvester (CPEH) designed to enable autonomous sensing and wireless data transmission in aircraft structures. Aircraft sections experience complex, multiple vibration modes during flight; however, the proposed harvester is specifically designed to exploit the oscillatory motion of the vertical tail unit (VTU) of a VUT-100 Cobra aircraft during the cruise phase. The energy harvester employs a clustered piezoelectric cantilever configuration incorporating magnetic stiffness nonlinearity, which enhances vibration-induced strain and enables effective frequency tuning. The nonlinear magnetic interaction broadens the operational bandwidth and improves energy conversion performance under low excitation amplitudes. The system is tuned to operate over a broadband frequency range of 110–130 Hz, with optimal performance achieved at acceleration amplitudes of less than 0.5 g, corresponding to the measured VTU vibration levels during the cruise phase of the flight. An experimental prototype was tested in the laboratory under aircraft cruise-phase vibration conditions, successfully achieving maximum power of 0.041 mW at optimum resistance of 390 KΩ and 5.45 mJ of stored energy in a 1000 µF capacitor within 10 min, confirming the feasibility of the proposed harvester for aircraft SHM applications.