Foam-based composites are advanced materials that combine lightweight design with high mechanical strength and stiffness, making them attractive for diverse engineering applications. Their mechanical performance is strongly influenced by foam morphology, including strut geometry in open-cell foams and cell wall topology in closed-cell foams. This study investigates the effect of these morphological features on the mechanical behavior of foam-based composites, considering both open-cell and closed-cell foams as matrix phases. A finite element-based numerical homogenization approach evaluates mechanical performance over a wide range of phase volume fractions and stiffness contrasts. The results reveal significant differences in stress distribution, load transfer efficiency, and overall mechanical response between the two foam morphologies. Open-cell foam composites, particularly those with cylindrical struts, show superior load-bearing capacity under high stiffness contrast. In contrast, closed-cell composites develop stress localization unless optimized with thin walls and dense reinforcement. The findings indicate that the mechanical efficiency is governed by three main factors: (i) phase stiffness contrast, determining how morphology affects performance; (ii) phase connectivity or interpenetration, controlling stress transfer through the stiff phase; and (iii) strut geometry, where rounded struts aligned with the load enable direct stress transfer while minimizing matrix deformation.

Due to the high degree of randomness in the microstructure of real closed-cell foams, many reported numerical models in the literature are not able to capture precisely the local morphological features found in solid foams geometry. This is still the main impediment that restricts the investigation of this novel material and motivates the development of a sophisticated 3D solid model, which describes properly the complex geometry of real closed-cell foams. In this regard, this paper presents an original approach to generate a realistic and accurate 3D computational model of irregular closed-cell foams with relative density control and detailed finite element analysis of their mechanical performance under quasi-static loading up to densification. The solid model is constructed based on spherical particles inflation simulation. It resembles the real foams in terms of local features such as cell walls irregularities and thickness variation. The modeling approach was successfully verified by comparing cell-morphological details of the generated models with those produced experimentally available in the literature and by the high-quality of obtained 3D printed models containing complex shapes and irregular cell wall thickness distribution. The evolution of spherical particles during the inflation process is analyzed based on finite element (FE) simulations. It was found that it can produce varying relative densities of foam due to the gradual decrease in the gap between the inflated particles, this makes the geometrical model of the foam suitable for studying the effect of local morphological characteristics on the mechanical performance of closed-cell foam material. To demonstrate that the compressive performance of the proposed closed-cell foam models can be controlled by relative density, 3D foam models were extracted from different inflation times and then subjected to quasi-static compression tests up to densification using the Abaqus software. The results confirm that the plateau stress can be expressed as a function of foam relative density, its accuracy is validated by comparing it to the closed-cell aluminum foam power law equation existing in the literature. The new design method offers suitable numerical models for AM technology, plenty of experimental works on closed-cell foam can be reduced for engineering applications.