Image-based modelling of open cell polymeric foams as simplified beam structures

Polymeric foams have many important applications in various industrial sectors, thanks to an excellent combination of properties. The study of the mechanical behavior of this type of material has important academic value and application prospects but poses important challenges because of their complex topology; numerical models faithful to their geometrical microstructure suffer from very high computational costs. This paper aims to develop a simplified beam element model of open-cell polymer foams based on X-ray computed tomography (CT) images, able to describe their compressive response with significantly improved computational efficiency. The images of the microstructure of a PPI20 polyurethane foam were obtained through CT scan. These images were then converted to 3D solid model, from which key morphological features were extracted. Based on these morphological features, an equivalent simplified beam element model was generated. A good quantitative agreement was found between simulations carried out with the two numerical models (solid and beam) and the compression experiments. In-situ compression tests performed in combination with CT scans also confirmed the ability of numerical models to describe the real deformation mechanisms of the foam. This simplified model demonstrates an accuracy comparable to the 3D solid model with vastly reduced computational effort, allowing for an efficient and accurate prediction of the mechanical properties of open cell foams.