Behavior of CFRP-UHPFRC-steel double skin tubular columns against low-velocity impact

Abstract

In this study, a total of six specimens were prepared and tested, and the dynamic response and damage mechanism of carbon fiber reinforced polymer (CFRP)-ultra-high performance fiber-reinforced concrete (UHPFRC)-steel double skin tubular (DST) columns against low-velocity impact were investigated. The effects of CFRP, impact energy, hollowness ratio and infilled concrete on the behavior of CFRP-UHPFRC-steel double skin tubular columns against low-velocity impact were studied. Moreover, the software LS-DYNA was used to simulate the CFRP-UHPFRC-steel DST columns against low-velocity impact, and the feasibility of the model was verified by comparing the simulation and experimental results. Based on the verified model, the damage evolution of the infilled concrete was investigated. Afterwards, parametric analyses were carried out using the validated finite element model. The results show that increasing the steel ratio and decreasing the slenderness ratio can improve the lateral stiffness and the lateral impact resistance of specimens. When the impact position is closer to the fixed end of the specimen, the global deflection decreases. Only binding CFRP within a certain range at the impact region can also have a good restraint effect on the specimen and can enhance the lateral impact resistance of the specimen. Furthermore, indenters with different shapes have different effects on the behavior of specimens against low-velocity impact.