Alternative Model of the Offset Deformable Barrier

The offset deformable barrier consists mainly of honeycomb blocks with highly anisotropic behaviour. These parts are made from several layers with aluminium foil that is glued and stretched to form the honeycomb structure. Simple compression tests show high stiffness and strength when the cell structure is folded while both stiffness and strength are significantly lower when the deformation mode is mainly bending of the thin foil. Remember that the strength of a honeycomb block is mainly determined by the width/thickness ratio of the cell walls. Therefore, shell elements are used to model the honeycomb structure, and an alternative model of the offset deformable barrier is made. Note that scaling is used extensively to limit the number of elements and thereby the computational time that is required. Both simulations and tests show that the typical deformation mode involve also transverse displacement of barrier parts, and when the honeycomb structure is folded this may be seen as the interaction between local and global buckling. This model seems able to predict both the force level and the transverse force components that are important to represent when designing bumper systems with respect to high-speed performance.