Effect of strain rate on dynamic responses of laterally impacted steel plates

Abstract

Quasi-static punching tests and low-velocity impact tests have been conducted to examine the plastic response and failure of clamped rectangular steel plates struck by hemispherical indenters. The length, width and thickness of plate specimens are 127, 76 and 1.4 mm, respectively. Experimentally obtained quasi-static and dynamic force-displacement responses are compared to reveal the influence of dynamic material characteristics on the impact behaviour of steel plates. The failure mode of laterally impacted plates is exposed to further illustrate the dynamic material properties. The experimental results are compared with numerical simulations performed by the LS-DYNA finite element solver. The finite element model includes defining the material strain hardening, strain rate sensitivity and critical fracture strain. A simplified method is proposed to characterise the material strain rate effect at varied plastic strains in the simulations. A good agreement is observed between experimental and numerical results, demonstrating the rationality of the material definitions in low-velocity impact. The paper contributes to enhance the industry practice in impact simulations of steel structures when only material quasi-static tensile tests are available.