Simulation of cellular materials using micro-scale model

Abstract

Cellular material is a typical micro-scale crushable material due to its special pore microstructures. The mechanical properties of a cellular material are usually determined from experimental testing and based on stress-strain curves for normal and shear loading. Since such tests are associated with a large amount of time and cost with regard to specimen preparation and test devices, an alternative way of determining the effective mechanical properties can be investigated using micro-scale modelling that is through virtual material testing. In this paper a finite element program LSDYNA is used to develop a micro-scale model for a cellular material honeycomb. In the micro-scale model of honeycomb, the cell walls are 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 cellular materials. The developed micro-scale model is validated through comparing the simulated results with the experimental information. The validated micro-scale model is then used to simulate the material responses under the static conditions. With the micro-scale structure model, the impact response such as progressive crushing of the honeycomb and layer by layer cell collapse can be also simulated, and consequently the dynamic material properties of honeycomb can be derived such as the plateau stress enhancement increase in the energy absorption capacity of honeycomb under different loading rates.