Micro-Inertia Effect and Dynamic Poisson'S Ratio of Closed-Cell Metallic Foams under Compression

A significantly decreasing influence of lateral constraint on the crushing stress with increasing loading rates has been found for a closed-cell aluminum foam. This interesting phenomenon may be interpreted by the micro-inertia effect and/or the decrease of Poisson's ratio in dynamic compression. In this paper, the three-dimensional Voronoi technique and the explicit finite element method are utilized to investigate the micro-inertia effect and dynamic Poisson's ratio of closed-cell metallic foams. The simulation results indicate that the micro-inertia effect plays little role in enhancing the plateau stress of metallic foams. The Poisson's ratio varies with the nominal strain and its peak value decreases as impact velocity increases.