Multiscale analysis and mechanical characterization of open-cell foams by simplified FE modeling

Foam materials are experiencing a great diffusion in the industrial field because of their numerous properties and adaptability to different purposes. At the same time, research efforts are addressed to define new fields of application and methodologies of foam simulation, capable of combining their behavior at macroscale to phenomena at microscale, i.e. ligaments level. In this paper, a FE beam modeling strategy for open-cell foams acting on different scales of analysis is described. At first, on the microscale, the definition of the fundamental Kelvin unit cell is outlined with a particular characterization of the intersection zone between ligaments, that is a critical issue to obtain an accurate simulation instrument. The repetition of the unit cell within the material domain allows to obtain the overall foam material and operate at the macroscale. The elastic properties at macroscale are derived by means of FE analysis and compared with both solid model and experimental results. The proposed simplified FE modeling, using equivalent beam elements having suitable mechanical characteristics, demonstrates high accuracy levels and substantially relieve the computational efforts required by the commonly employed solid models.