Elastic finite element analysis on cross-sections of random hollow sphere structures

Abstract

This paper addresses elastic analysis based on 2D finite element models for metallic hollow-sphere structures. In the first part, the influence of micro-porosity on the elastic behavior of sintered metallic hollow sphere wall material is investigated. Young's modulus of the metallic hollow sphere wall material is found to linearly decrease with increasing micro-porosity ranging up to about 45%. In the second part, elastic parameters for metallic syntactic foams (MSF) consisting of thin or thick walled hollow spheres, and for epoxy containing spherical pores are studied. Data obtained from finite element models are compared with theoretical predictions based on the rule of mixtures developed elsewhere and found to be in good agreement with each other for MSF but not for porous epoxy. The shear modulus of MSF with thin-walled hollow spheres was found to increase with increasing volume fraction of matrix whereas that of MSF with thick walled hollow spheres was found to decrease. Specific Young's modulus of MSF with thin-walled hollow spheres was also found to increase with increasing foam density whereas that of MSF with thick walled hollow spheres was found to decrease. Poisson's ratio obtained was relatively low for porous epoxy matrix material but high for MSF with thin or thick-walled hollow spheres.