Post-collapse characteristics of ductile circular honeycombs under in-plane compression

The post-collapse behaviour of a circular honeycomb material under in-plane compression is analysed in order to estimate the effect of the structural topology on the material strength. A structural approach using the limit analysis and the concept of an equivalent structure is employed to describe the large plastic deformations during post-collapse process. Based on some published experimental results (International Journal of Solids Structures 36 (1999) 4367-996) and our numerical simulations, certain deformation patterns are constructed depending on the direction of loading, and the corresponding post-collapse load-carrying capacities during large deformation until densification of cells are presented. The present analysis shows that the post-collapse stress associated with an equi-blaxial compression is not excessively larger than the corresponding uniaxial stresses, in contrast to those of hexagonal honeycombs in response to biaxial loading. This behaviour is attributed to the different deformation mechanism as the curvature of a cell wall invokes bending without stretching. The influence of the size of the connecting segment between two neighbouring cells is studied, showing that the "shape" of the limit surface varies significantly depending on this connection. (c) 2005 Elsevier Ltd. All rights reserved.