A compact quasi-zero stiffness metamaterial for energy absorption and impact protection

Abstract

A compact mechanical metamaterial for impact protection is proposed in this study. During compression, the unit cell of the metamaterial exhibits quasi-zero stiffness (QZS) and quasi-zero Poisson’s ratio (QZPR) characteristics, along with large densification strain, making it suitable for protection against low-speed impacts. Firstly, the parametric geometric model of the metamaterial is established, with sinusoidal thin-walled structures serving as the primary load-bearing units. The grid structures are employed to connect the thin-walled structures into a unified system. Secondly, to shorten the design cycle, numerical methods for the mechanical properties of the buffer structure are developed. The motion equation of the thin-walled structure are expressed in terms of arc length coordinates and solved using the Runge–Kutta method and the shooting method. The grid structure deformation and the effect of material plastic reinforcement on the structural mechanical response are analyzed, and the energy absorption (EA) of the buffer structure is calculated. Both simulation and experimental results demonstrate the high accuracy of the proposed calculation method. Lastly, drop hammer experiments are conducted to evaluate the impact mitigation performance of the designed buffer structure. The results indicate that the structure exhibits excellent impact mitigation capabilities, highlighting its potential for practical applications.