Numerical Study On Yield-Surface Of Metal Foam Material

Foamed pure aluminum and various foamed aluminum alloys are a kind of novel light-weighted functional materials characterized by mass holes dispersed in the parent material, which has many advantages that are superior to those of traditional metal and polymer foam. It has the properties of both functional material and structural material. Moreover, it is a new-style material with great potential.In this paper, we discuss the yield surface and subsequent yield surface of the open cell aluminum in micro-mechanical analysis method with FEA (Finite Element Analyses) software. An open cell aluminum model of micro-mechanical was established with 3D Voronoi Cell. The deformation of the model in some typical loads was simulated with FEA method, and two major deformation mechanism of the metal foam material was analyzed via results above. When tension, elasto plasticity deformation is the mainly way of the deformation, while compression, buckling is also an important way of the model deformation besides the elasto plasticity deformation. The yield surface of the model may not a cylinder, but a surface with taper along the hydrostatic pressure line and with some depression on it, which are mainly due to the inexistence of incompressibility of the plastic volume of the model.The subsequent yield surface of the model was also calculated by FEA method. The revolution law of the subsequent yield surface was considered with Lode parameter and the invariant value of the stress component, which was induced by the inexistence of incompressibility of the plastic volume of the model either.