This study investigates the trend and reason for the decrease in compressive stress with increasing pore-arrangement irregularity in directional porous metals. Compressive simulations were conducted on models with regular and various degrees of irregular pore arrangements via finite-element analysis, with A6061-O used as the base material. An irregular arrangement was generated by randomly shifting each pore of a regular arrangement while maintaining the porosity. The degree of irregularity in the pore arrangement was evaluated as the average displacement of the pores normalized by the pore diameter. As the irregularity of the pore arrangement increases, a localized plastic strain is observed from small compressive strains in band-like regions, which later exhibits deformation bands at large compressive strains. A decrease in the compressive stress is identified as an increase in the average plastic strain within these band-like regions. This relationship is well described by an approximate linear correlation with a coefficient of determination of 0.76.
Yano et al. (Tue,) studied this question.