Energy of quasi-zero stiffness energy harvester under strange non-chaotic attractor.

This study investigates the Quasi-Zero Stiffness Energy Harvester (QZEH), a nonlinear, multi-stable system designed for enhanced energy extraction from vibrating mechanical devices. Nonlinear harvesters, like QZEH and bistable systems, operate over a wider frequency range, effectively capturing energy from broadband or irregular inputs, but can lead to complex behaviors. Maintaining a quasi-periodically forced QZEH in a periodic state is challenging due to the intricate interaction between the system's nonlinear dynamics and the input's incommensurate frequencies. While periodic solutions are typically associated with higher energy yields than chaotic ones, we report a novel dynamical domain under quasi-periodic excitation. Surprisingly, this regime, characterized by a strange non-chaotic attractor, demonstrates a significantly higher energy harvesting efficiency than chaotic motion. This finding challenges conventional expectations and opens new avenues for optimizing energy harvesters. We examine robustness under practical conditions by analyzing the effects of additive white noise on the QZEH system. The results show that increasing noise intensity progressively erodes the basin of strange nonchaotic attractors, while energy harvesting performance remains stable in the single-attractor regime. This discovery represents a significant advancement in energy harvesting technologies, offering a pathway to achieve higher energy extraction by utilizing nontraditional dynamical behaviors.