A microsphere-based material model for open cell metal foams

Abstract

Cellular materials, such as open cell metal foams, consist of a complex microstructure effecting the global material behaviour. The characterisation of the macroscopic material behaviour is complex and requires a multitude of different experiments. Material models that treat the metal foam as a continuum can describe the observed behaviour from the experiments, for example the yield surface. But for different metal foams, the experimental procedure has to be performed before the macroscopic material models can be adapted to the experimental results. Simulations with the entire microstructure lead to large computational effort and are not efficient for simulations on components. The aim of the present contribution is to describe the material behaviour on the macroscopic level with a material model explicitly related to the microscopic level. It is advantageous that the experimental effort for determining the macroscopic material behaviour is reduced by experiments on individual struts. The results of the experiments are described by 1D constitutive equations and are extended to a 3D material model achieved by generalising the 1D constitutive laws with a microsphere-based model. The macroscopic simulations are compared with tensile and compression tests on 10 ppi aluminium foams to validate the model.