Response of closed-cell aluminum foams under static and impact loading: Experimental and mesoscopic numerical analysis

Abstract

This paper investigates the mechanical behavior and mesoscopic deformation of closed-cell aluminum foam under static and impact loading. Two groups of closed-cell aluminum foam specimens are prepared for static and dynamic tests, respectively. The configurations of the specimen (such as porosity and base material) are considered. The mechanical response and the energy absorption capability are studied. In order to reveal the mesoscopic deformation mechanism, a mesoscopic model is developed considering the randomness of pores in size and distribution. The dynamic response under low and high impact velocity is investigated based on the mesoscopic model. Insights into the deformation mode are conducted. The collapse and the fracture of cell-walls under different impact velocity are discussed. It reveals that the mesoscopic deformation is closely related to the impact velocity. Porosity is also an important aspect on the dynamic property. At low impact velocity, the plastic deformation can be found in the middle domain of the specimen. At high impact loading, a dynamic mode is formed, in which the collapse and fracture of cell-walls is mainly located near the impact end. At a very high impact velocity, a shock mode can be found, forming a strain localization at the impact end for the metallic foam. It leads to significant improvements on the dynamic plateau stress and the energy absorption capability. This originates from the inertia effects.