Internal resonance vibration-based energy harvesting

Taking advantage of undesirable ambient vibration resources, vibration-based energy harvesters (VEHs) aim to power smart electronic devices by converting kinetic energy into electricity via the designed resonance regions for optimized power levels. Realistic environmental resources have led to the research field predominantly focused on the nonlinear themes-broadening operational bandwidth through inherent and externally induced nonlinearities. Internal resonance, associated with nonlinearity in a multi-degree-of-freedom system, has remained an active research topic due to its rich dynamic behaviors since the last century. The effects of nonlinear modal couplings permit energy transfer between the internally coupled modes and have yielded various applications from vibration control of large-scale facilities to sensing in micro-electro-mechanical systems (MEMS). With double-jump, saturation phenomena, and flexibility of scavenging high-amplitude vibration sources at low ambient frequencies and outputting higher frequency responses, the idea of internal resonance energy harvesters gradually emerged and matured within a decade. The review aims to summarize the utilization of the internal resonance in VEHs through underlying principles and mechanisms, assess the performance of the state-of-the-art devices from a mechanical and structural point of view, and provide tentative guidance for future investigations on internal resonance vibratory energy harvesting.