Characterization of mechanical properties of metallic foams by instrumented indentation test

Abstract

In this study, the spherical indentation tests with a spherical rigid indenter of 5 mm radius were used. The inelastic behaviour of metallic foam was considered as an isotropic crushable foam constitutive model of Deshpande and Fleck which has been shown experimentally that their model can be applied to aluminum foams. The spherical indentation test was modeled by finite element method. A 2D axisymmetric model was developed. Practically, the size of the indenter tip should be reasonably large compared to the size of the cells/pores in the specimen and the indentation depth should also be reasonably large so that the indentation response does reflect the averaged material behaviours, which are described by the aforementioned constitutive model. The applied load on the indenter versus its displacement was obtained under different metallic foam mechanical properties. Numerical results from the finite element simulations are used to obtain the dependence of the indentation response on the metallic foam material parameters which characterizes the plastic deformation of metallic foams. Finally, the stress–curves and the elastic modulus of different foams are obtained by the indentation curve, which is obtained by FEM.