Abstract:

Quasi-zero-stiffness (QZS) isolators hold considerable promise for the development of low-frequency broadband vibration isolation platforms, particularly in aerospace, transportation, and civil engineering. However, stringent requirements for integration, lightweight design, reliability, and customization in high-end equipment limit the practical application of conventional QZS isolators. To address this challenge, this paper proposes a novel modular reconfigurable QZS isolator (MRQI) composed of elastic modules and complementary rigid modules, which is lightweight and exhibits programmable QZS characteristics. The elastic modules adopt a multi-section beam configuration with compliant joints to reduce stress concentration. Notably, this modular design not only endows the MRQI with reconfigurable and programmable properties but also simplifies fabrication from a three-dimensional (3D) additive manufacturing process to a two-dimensional (2D) planar process, thereby reducing manufacturing errors caused by spatial structural distribution. The results reveal that the MRQI achieves multi-stage QZS characteristics, enabling decoupled control of the QZS range and loading capacity, while each QZS range covers 80% of its corresponding stroke range. Moreover, the MRQI maintains robust low-frequency isolation performance against variations in excitation amplitude and loading mass under both displacement and force excitation conditions, provided that the displacement remains within the QZS ranges. Compared with linear isolators, the MRQI reduces the starting isolation frequency by more than 84%. Both the static and dynamic tests confirm the accuracy of the theoretical analysis. Overall, this work presents a novel approach for constructing scalable, integrated, lightweight, and customizable QZS structures, offering a promising framework for the practical engineering applications of QZS isolators.

Key words: passive vibration isolation, quasi-zero-stiffness (QZS), discrete assembly, user-defined mechanical properties, multi-section buckling beam