A multi-cell FE-model for compressive behaviour analysis of heterogeneous Al-alloy foam

摘要

Compressive mechanical behaviours of closed cell Al-alloy foams produced by melt based and powder metallurgical methods were investigated by a finite element model composed of multiple unit lattices. The unit lattice consists of spherical and cubic sections possessing a thickness ratio between them. A Gaussian distribution of the relative density among the lattices and the random allocation of lattices were implemented in the model to address the structural heterogeneity. The constitutive relation for the lattice material was determined by a nondestructive instrumented sharp indentation test on the cell wall. The simulated compressive stress - strain curves for the ductile Al - Si - Ca foam were found to be in good agreement with the experimental ones over the entire strain range while the resistance of brittle Al - Si - Cu - Mg foam to the deformation turned out to be lower than that predicted by the model after about 0.50 strain. The discrepancy between experimental and simulation results for Al - Si - Cu Mg foam in high strain range was associated with the disintegration of cell walls broken by the large deformation.