Effect of low-velocity impact damage location on the stability and post-critical state of composite columns under compression

This study investigates the effect of low-velocity impact damage location on the stability and post-critical states of thin-walled channel section columns under compression. The profiles were made of GFRP with a symmetric ply orientation relative to the mid-plane of the laminate. The damaged area (its shape and size) was defined based on the results of experiments performed on composite plates and reported in the literature. The composite damage was modelled using a simplified damage model (SDM), in which the thickness of individual plies of the laminate was reduced depending on the impact energy. The numerical analysis by the finite element method led to development of a series of numerical models of the thin-walled channel section column with the SDM by placing the damaged area in different places of the walls and web of the C column. The composite damage in the post-critical state was determined by the progressive damage criterion according to which composite damage initiation is described by the Hashin criterion whereas damage evolution is described by the energy criterion.