Image-based finite element analysis of porous aluminum and its accuracy examination

Porous aluminum can be a good shock absorber, and its collapse behavior and shock absorbing property is desired to be optimized by the pore structure. To unravel the collapse mechanism, we have utilized the image-based finite element analysis. The pore structure was captured by the micro-focus X-ray computed tomography, and the finite element model was automatically and easily generated by using the uniform cubic element, that is, voxel element. The elastic property of two samples of porous aluminum was evaluated by the finite element analysis, and compared with the experimental result of static compression test. The effect of element size on the elastic numerical results was also investigated by changing the size of voxel element. However, the elastic property obtained by the finite element analysis completely differed from the initial gradient of the stress-strain curve obtained by the experiment. On the other hand, the elastic-plastic analysis gives a good estimation of the initial gradient of the stress-strain curve. We concluded that the compressive collapse behavior was affected by the elastic-plastic property of material along with the high stress concentration from the beginning of contact with the compression plate and the plateau region was realized by the finite deformation of the cell walls.