Structure-property relationship of open-cell Cu foams under compression: A micro-CT-based finite element study

Open-cell copper foams are promising for energy absorption, yet the systematic influence of pore density (PPI) on their compressive deformation and energy absorption has not been fully explored. In this work, realistic CT-reconstructed finite element models of 20, 40 and 60 PPI foams were developed, and the annealed copper matrix was described by the Ludwik hardening law. Quasi-static compression simulations were validated through size convergence and kinetic-to-internal energy ratio checks. The results show that yield strength increases monotonically with PPI. The 20 PPI foam deforms via localized bending of struts, forming a collapse band and a lower plateau stress. The 40 PPI foam exhibits the highest energy absorption efficiency (0.349) and the largest densification strain (0.577), making it suitable for applications requiring large deformation at nearly constant stress. The 60 PPI foam achieves the highest energy absorption both at the densification strain (2.181 MJ/m 3 ) and at ε = 0.7 (3.760 MJ/m 3 ). These findings quantify how PPI governs the compressive behavior of open-cell copper foams and provide guidance for selecting optimal pore densities in energy-absorbing applications.