Dual-function of isolation and energy harvesting via a spatial cam-induced multi-region quasi-zero-stiffness mechanism

With the rapid development of smart industrial systems, low-frequency vibration isolation and energy harvesting have attracted increasing research interest. Inspired by spatial cam mechanisms, this study proposes a dual-functional integrated design that simultaneously achieves low-frequency vibration isolation and piezoelectric energy harvesting. The proposed device combines a spatial cam, piezoelectric flexible beams, and linear springs to realize quasi-zero-stiffness (QZS) behavior. Owing to the multi-periodic profile of the spatial cam, the structure exhibits multiple QZS intervals, enabling effective low-frequency isolation under varying payloads and alleviating response coupling and alignment issues commonly encountered in series-type QZS configurations. The piezoelectric beams undergo controllable deformation imposed by the cam profile, allowing efficient conversion of low-frequency vibration energy into electrical energy while preventing excessive stress in the piezoelectric material. In addition, tailoring the Poisson’s ratio of the piezoelectric beam substrate further enhances the harvested power. Theoretical analysis clarifies the effects of the spatial cam contour and the structural parameters of the piezoelectric beams on the static characteristics of the proposed CS-QZS-VIEH, establishing the conditions required to achieve multiple QZS regions. A nonlinear electromechanical coupled dynamic model is developed to investigate the system response, revealing how key mechanical and electrical parameters jointly govern vibration isolation and energy-harvesting performance. The negative Poisson’s ratio configurations of three piezoelectric beams are optimized using a genetic algorithm and experimentally validated. Static experiments demonstrate QZS behavior at loads of 6.6 N and 14.0 N. Under a displacement excitation of 6 mm, the CS-QZS-VIEH exhibits initial isolation frequencies of 2.6 Hz and 2.3 Hz for the two loading conditions, representing reductions of 56.8% and 47.7%, respectively, compared with an equivalent linear isolator. The corresponding peak transmissibility is reduced by 35.5% and 16.7%. Moreover, stable energy-harvesting performance is maintained within the isolation band, and the peak output power of the negative Poisson’s-ratio piezoelectric beams is increased by 65.6% relative to the conventional configuration. Both theoretical and experimental results indicate that the proposed CS-QZS-VIEH effectively integrates low-frequency vibration isolation and piezoelectric energy harvesting, offering a promising solution for vibration mitigation in marine, terrestrial, and aerial platforms, as well as for self-powered microsensing applications, and providing useful guidance for the design of multi-load QZS systems.