Numerical analysis of metallic foam using microstructure model

Abstract

It has become a critical issue that the human life and civil facility have been threatened by the increasing terroristic explosive attack. The application of cellular materials is an effective and feasible measure to mitigate blast and impact loading on buildings due to their energy absorption capacity. The Finite Element code such as LSDYNA has been used to simulate the mechanical behaviours of cellular materials. However, most of numerical models regarded the cellular materials as homogeneous materials on the macro level which may affect the accuracy of simulation, because none of them can reflect the pore structure of cellular materials, especially for the irregular metallic foam structures. Therefore, in this study, two main microstructure models (2D/3D metallic foam) were developed for numerical simulation of closed-cell metal. In the microstructure model of metallic foam, the cell walls were represented by thin shell elements and the solid wall material of the cells is modelled as bi-linear stress-strain relationship based on the material properties of the cell wall material of metallic foam. The numerical models were validated through comparing simulated results with analytical values of plateau phase stress-strain response under static condition. With the validated microstructure models, a series of parametric studies were conducted, in order to have a better understanding about the mechanical properties of closed-cell metallic foam. The emphases of this study were on the differences between static and dynamic performances of closed-cell metallic foam specimens in both 2D and 3D cases, the relationship between dynamic increase factor and nominal strain rate.