Closed cell porous Al has extremely low mass and provides high energy absorption performance. However, because of its low tensile strength, it has been expected to be used as porous Al filled members with a dense surface material, as well as to clarify its axial crushing performance.
   In this study, the effect of the axial crushing performance by porous Al filled members, the impact crushing test using several hollow forms and porous Al filling in different ways were examined, and FEM analysis was carried out.
   As a result, the energy absorption was increased about 1.6 times by press filling, and about 2.0 times by glue-press filling porous Al from the sum of individual one of hollow forms and porous Al; thus, the porous Al filled members provided the interaction effect. Based on the test result and the elastic-plastic FEM analysis in which the crushing behavior matched the test result, it was proved that the energy absorption was increased since the buckling transformation to inside forms was restrained. Moreover, porous Al penetrates inside transformation by glue-press filling and press filling porous Al, and accordingly the deformation resistance in the compression direction increased. This increase of the deformation resistance in the compression direction causes forms axisymmetric collapse mode, and the interaction effect of porous Al filled members can be expressed in as much that the form thickness apparently increases due to the effect of the mass of filling material. The estimate equation of the mean crushing stress as an index of the energy absorption well-matched the test result. Therefore, it was proved that the mass of filling material contributes as an additional thickness of forms. In addition, the interaction effect is decided by a filling method.