Modelling of MHS cellular solid in large strains

The stress-strain characteristics of metal hollow sphere (MHS) material are obtained in relatively large strains under uniaxial compression in two characteristic loading directions. Based on the hypothesis of periodic repeatability of a representative block, large deformations of the material are modelled when assuming point connections between the spheres. The elastic deformations are neglected and a rigid perfectly plastic model is assumed for the base material. A structural approach using the limit analysis and the concept of an equivalent structure are then employed to describe the large plastic deformations during post-collapse process of metal hollow spheres, which undergo mainly a snap-through deformation. Stress vs. material density relationships are proposed for different strain levels in each direction of loading. The obtained results can be used to estimate the energy absorbing capacity of MHS materials under quasi-static loading. The theoretical predictions are compared with some test results and reasonable agreement is shown. (C) 2006 Elsevier Ltd. All rights reserved.