Effect of morphology, topology and anisoptropy of open cell foams on their yield surface

Abstract

An efficient numerical method (Storm et al., 2016) is applied to determine the limit of the macroscopic elastic domain and the evolution of the yield-surface of open-cell foams. The influence of several important morphological properties of foams, as anisotropic foam pores, material distribution and strut curvature, is investigated. Furthermore, an analytical solution for the initial yield surface of the Kelvin cell model with anisotropic pores is presented. The impact of topology is analysed by comparing the Kelvin cell to a Weaire–Phelan and a relaxed Voronoi foam. Through the comparison of the results obtained by a structural mechanics approach (beam model) and a continuum model, the strong limitations of beam models become evident. To benefit from the numerical efficiency of beam models, hybrid-models are proposed and are shown to give accurate results. Finally, a modified Bigoni–Piccolroaz criterion is presented, which allows to describe the presented isotropic yield surfaces and simplifies the parameter identification.