Hadi Partovi Aria - M.Sc. Student, School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran
Arash Bahrami - Assistant Professor, School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran
Ali Sadighi - Assistant Professor, School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran

The present article proposes the idea of multi-frequency excitation to harvest energy from low-frequency ambient vibrations. A nonlinear piezomagnetoelastic set-up, operating in the monostable mode, is considered. Due to nonlinearities being present in the system, a multi-frequency excitation gives rise to complicated phenomena such as combination and simultaneous resonances. We propose the idea of multi-frequency excitation and employing secondary resonances such as combination and simultaneous resonances occurring in nonlinear systems. Nonlinear differential equations governing the harvester dynamics are obtained based on the Hamilton extended principle and solved using the direct harmonic balance method. Numerical results are presented for an actual energy harvester subjected to a dual-frequency excitation. It is ascertained that multi-frequency excitation and exploiting combination and simultaneous resonance result in a significant enhancement in the harvester output voltage and power. It is also found that simultaneous resonance is more effective in improving the harvester performance than combination resonances

Energy Harvesting, multi-frequency excitation, nonlinear resonances, piezomagnetoelastic