Unit-cell models were developed for open-cell metallic foams in order to predict their effective elastic moduli and the plastic collapse strengths. One was for the empty open-cell and the other for the open-cell filled with elastic material. The models are based on the metallic ligament frames of tetrakaidecahedral shape. The elastic filler was modeled as elastic foundation to the metallic ligament frames. The frame structures of the unit-cells were analyzed using the finite element method. The plastic collapse strength was determined when the joints of ligaments became plastic hinges under the assumption of elastic-perfectly plastic material behavior of the metallic material. Both elastic modulus and plastic collapse strength were computed using a single step of finite element analysis using a very small number of finite elements without any iterative or incremental procedure. As a result, the unit-cells are computationally very efficient. In order to validate the unit-cell models, experiments were also conducted. The experimental data agreed very well with the predicted values of both stiffness and strength. In addition, the SEM (Scanning electronic microscope) image confirmed the failure modes assumed in the study, i.e. plastic collapse of ligaments.
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