Splitting and curling performance of metal foam-filled circular tubes.

In this paper, analytical and experimental methods are used to study the deformation mechanisms of metal foam-filled circular tubes in axial splitting and curling modes. Metal foam-filled tubes with prefabricated cracks are placed on a die, and axial compressive experiments are conducted. In the experiments, the force–displacement curves of metal foam-filled tubes are measured, and the deformation modes of metal foam-filled tubes are observed. An analytical model is established for metal foam-filled circular tubes in axial splitting and curling modes. In the analytical model, energy is dissipated by splitting, curling, and plastic bending of the tubes, as well as by friction between the tubes and die and foam compression. The analytical, numerical and experimental results are compared. The analytical model captures the experimental results reasonably well, and the numerical results are in good agreement with experimental ones. It is found that, in the stage of steady deformation, the axial compressive force increases with the increase in the number of prefabricated cracks, the ratio of radius to the wall-thickness and the semi-angle of conical die. The axial compressive force decreases with the increase in the ratio of the prefabricated-crack length to the wall-thickness. Foam-filled tubes have a higher specific energy absorption than sandwich tubes. [ABSTRACT FROM AUTHOR]