Modeling of ductile damage in metal foams

摘要

A numerical model for the elasto-plastic and ductile damage behaviour of a low-density open-cell metal foam is presented based on a three dimensional random network of slender struts. The finite element formulation for the behaviour of the struts makes use of the Timoshenko beam theory. A layered approach is adopted to simulate the progressive growth of plasticity and void volume fraction in the struts due to ductile damage effects from the extreme fibers towards the neutral axis. The result is an efficient numerical model for a representative volume element of the foam which can be used as material model in each integration point of a macroscopic Finite-Element-Model. The numerical studies indicate that the collapse of the foam structure on the meso-scale is initiated by a few randomly distributed struts. The bending and buckling of the struts lead to formation of plastic hinges with localized growth of ductile damage.