A quasi-zero-stiffness device capable of vibration isolation and energy harvesting using piezoelectric buckled beams

A quasi-zero-stiffness (QZS) device is proposed for both vibration isolation and energy harvesting based on a concept of converting part of the vibrational energy into electrical energy and concurrently reducing the energy transmitted to the vibration receiver. The proposed device is constructed by four piezoelectric buckled beams and a vertical spring. The structural layout of the piezoelectric buckled beams has two benefits: firstly it produces negative stiffness in the vibration direction and thus offers the benefit of lowering the beginning frequency of isolation; secondly it always enables large strain and stress for the piezoelectric patches and thus leads to higher electrical output. The harmonic balance method is employed for the dynamic analysis based on the electromechanical coupled equations. The isolation performance is compared with a linear isolator and a conventional QZS isolator, which indicates that the proposed device can achieve lower isolation frequency and lower peak transmissibility. The energy harvesting performance is compared with the cantilever-beam energy harvester, which indicates that the proposed device can achieve higher output power and lower operating frequencies. The superior performances are also demonstrated by experiments, in which the lowest isolation frequency of 2.5 Hz and the maximum output power of 8.31 mW are obtained.