Meso-mechanical study of collapse and fracture behaviors of closed-cell metallic foams

Metallic foam is a typical porous material with heterogeneous mesostructure. The complex influences of the porous structure on the mechanical properties of metallic foam are not well known yet and this remains a crucial problem in the ability to predict and optimize the mechanical properties of foam materials. Here we explored the three dimensional Voronoi structure to model the meso-structure of metallic foam. The average pore size was controlled by the number of seeding points used to construct the Voronoi structure and the porosity was controlled by calibrating the cell wall thickness. In addition, the concept of pore irregularity was introduced to try to further quantify the description of the heterogeneous structure. The correlation between the pore irregularity variation and the plastic response variation suggests inclusion of the measurable meso-structural parameter would improve the constitutive modeling of foam materials. The plastic and the cracking behavior of pores at the mesoscale under large compressive deformation and tensile deformation were studied and the excellent compressibility of metallic foams can be attributed to the formation of multiple plastic bands while the poor stretchability is due to that only one damaged plastic band can be formed. (C) 2013 Elsevier B. V. All rights reserved.