A mechanical model of cellular solids for energy absorption

Cellular materials have a variety of applications in the fields of packaging and mitigation in the case of impact of vehicles, due to their ability to protect goods by absorbing energy. To design energy absorption systems, it is necessary to use predictive models of cellular materials. The models must describe the stress-strain behavior then energy absorption characteristics can be evaluated. Moreover, it must consider affecting factors like strain-rate. Modeling the influence of the density helps designer in selecting the best foam solution. In previous works the authors already presented models able to describe the quasistatic stress-strain behavior of several cellular materials. The current paper presents a general model able to describe the mechanical characteristic of a much larger variety of cellular materials including metal foams and considers the influence of strain-rate. Among the considered materials there are the Foaminal® foam and APM® aluminum foams. The model is fitted to experimental tests with parameters identified based on experimental data. Tests include quasi-static, dynamic, and impact tests in different loading conditions. It will be shown that the proposed model is fundamentally suitable for most materials, virtually any foamed material, and it is a useful tool for designers in the mentioned areas.