<p>This study investigates the mechanical properties and deformation behavior of closed-cell aluminum foam under quasi-static compression through a combined experimental and numerical simulation approach. An improved decahedral cell model was developed based on the periodic unit cell method and compared with the commonly used Kelvin cell model. Finite element simulations of the compression process were conducted using ABAQUS software to systematically evaluate the applicability of both models in predicting the mechanical properties and deformation modes of aluminum foams. The influence of pore size on mechanical properties was further analyzed. The results indicate that the decahedral model more accurately captures the “X-shaped shear collapse band” and exhibits smaller lateral expansion, demonstrating closer agreement with experimental observations. The deviations in mechanical property predictions were below 12% for both models, with a discrepancy of less than 2% between them. Additionally, the variation in pore size has a considerable influence on the mechanical properties and deformation patterns of the aluminum foam.</p>