Damage assessment of braided composite tube subjected to repeated transverse impact

In this study, damage behavior and failure mode of braided composite tube subjected to repeated transverse lowvelocity impact were investigated by combining experimental and numerical methods. The effects of impact energy (2.0 J, 5.6 J and 10.5 J) and impact position (identical, adjacent and opposite positions) on impact responses were evaluated. A finite element (FE) model with high computational efficiency was also established to predict the effect of single impact on the repeated impact response by varying boundary conditions. When subjected to single impact, the braided tube presented delamination-dominated damage behaviors caused by obvious structural deformation. The top part sunken and both lateral sides bulged, were found to have correlation with the mechanical response of tube with respect to initial scope and peak load, respectively. The delamination area increased at higher impact energies due to increasing shear stress caused by adjacent braided layers. Delamination induced by the first impact had different role on repeated impact responses. At identical position, it caused larger sinking deformation at top part of the tube and thus a lower initial scope. At adjacent position with impact energy of 5.6/10.5 J, the delamination damage caused a reduced resistance to bulging deformation at one lateral side of the tube, leading to a lower peak load. At opposite position, it had no obvious influence on repeated impact response.