Multi-scale impact resistance of flexible microporous metal rubber: Dynamic energy dissipation mechanism based on dynamic friction locking effect

Abstract

Flexible microporous metal rubber (FMP-MR) is widely used in national defense applications, yet its mechanical behavior under high-speed impact conditions remains insufficiently explored. In this study, dynamic and static experiments were conducted to systematically investigate the mechanical response of metal-wrapped microporous materials under impact loading that spanned 10⁶ orders of magnitude. By combining a high-precision numerical model with a spatial contact point search algorithm, the spatio–temporal contact characteristics of the complex network structure in FMP-MR were systematically analyzed. Furthermore, the mapping mechanism from turn topology and mesoscopic friction behavior to macroscopic mechanical properties was comprehensively explored. The results showed that compared with quasi-static loading, FMP-MR under high-speed impact exhibited higher energy absorption efficiency due to high-strain-rate inertia effect. Therefore, the peak stress increased by 141%, and the maximum energy dissipation increased by 300%. Consequently, the theory of dynamic friction locking effect was innovatively proposed. The theory explains that the close synergistic effect of sliding friction and plastic dissipation promoted by the stable interturn-locked embedded structure is the essential reason for the excellent dynamic mechanical properties of FMP-MR under dynamic loading conditions. Briefly, based on the in-depth investigation of the mechanical response and energy dissipation mechanism of FMP-MR under impact loads, this study provides a solid theoretical basis for further expanding the application range of FMP-MR and optimizing its performance.