Random equilateral Kelvin open-cell foam microstructures: Cross-section shapes, compressive behavior, and isotropic characteristics

Abstract

Representative volume elements of random equilateral Kelvin open-cell microstructures were modeled for the open-cell foam. We adopted the periodic boundary conditions developed in our previous research. The quasistatic compression properties of the representative volume elements in random Kelvin open-cell aluminum foam samples, both with different relative densities and different cross-sections of the beams in the structures were investigated. The results show that the features of the stress–strain curves in the representative volume elements with different relative densities and different cross-sections were similar, and the relationships between the yield strengths and relative densities of representative volume elements with four different cross-sections all agreed well with the quadratic power function. Among the representative volume elements with four different cross-sections, the yield strengths of the representative volume elements with a Plateau border cross-section were significantly larger than in representative volume elements with other cross-sections, while the yield strengths of representative volume elements with circular cross-sections were smaller than in representative volume elements with other cross-sections. This indicates that the simulation results of the compression strengths for open-cell foam in which the representative volume elements with circular cross-sections were employed are significantly smaller than their actual values. The main reason for this is that the moments of inertia in the Plateau border cross-sections are significantly greater than in the circular cross-sections of the same area. Our investigation results revealed that the compression responses of the representative volume elements for random equilateral Kelvin open-cell microstructures demonstrate isotropic behavior on the xoy plane, the yoz plane, and the xoz plane.