New designed quasi-zero-stiffness metamaterial for aerospace low-frequency vibration isolation

In view of the core requirements for low-frequency vibration isolation in the aerospace field, as well as the problems of complex design of traditional quasi-zero-stiffness (QZS) structures and insufficient bearing capacity of soft materials, this paper proposes a parallel cosine-beam QZS metamaterial. The structure realizes a stable QZS effect within a specific displacement range, taking into account the characteristics of high static load-bearing and low dynamic stiffness. The force-displacement model of a unit cell is established. The dispersion relation is derived by coupling the lumped-mass-spring model and Bloch’s theorem to analyze its local resonance bandgap characteristics. The quasi-static and vibration attenuation performances are verified through finite-element simulation and experiments. The results show that the pre-compression can reduce the starting frequency of the bandgap by up to (Formula presented) (Formula presented). In the experiment, the overall bandgap occupation rate observed in the range of (Formula presented) (Formula presented) is approximately (Formula presented) (Formula presented), demonstrating excellent low-frequency wide-band vibration isolation ability. This structure features a simple design and flexible parameter tuning. It is suitable for additive manufacturing and can be transitioned to metal materials. It is applicable to scenarios such as micro-vibration suppression of spacecraft and protection of ultra-precision equipment, providing an engineering path for low-frequency broadband vibration isolation.