Crushing analysis of metal honeycombs

A method for determining the crushing strength of hexagonal cell structures subjected to axial loading is given. The method is based on energy considerations in conjunction with a minimum principle in plasticity. The problem is shown to be equivalent to the analysis of a system of collapsing angle elements undergoing bending and extensional deformations. The theory is first developed for an arbitrary angle between panels and then is specified for the 120° angle, appropriate for the hexagonal cell structures. Simple formulas are derived relating the crushing force and the wavelength of the local folding wave to the wall thickness and diameter of the cell. The theoretical solution has been compared with experimental results published in the literature and an excellent correlation has been obtained for the wide range of geometrical parameters involved. This solution replaces the less accurate earlier analysis of the same problem due to McFarland. The purpose of this study was to provide a simple and rational means by which hexagonal cell structures can be designed for use as energy absorbers in impact or impulsive loading situations.