Dynamic response and failure mode of steel-concrete composite panels under low-velocity impact

There are two types of failure modes when a steel-concrete composite panel (SC panel) is subjected to low-velocity impact, local punching failure mode and overall flexure failure mode. Current studies have mainly focused on the former. To analyze the dynamic response process and mechanism of local punching failure, drop hammer impact test of seven SC panels, and static loading test of one SC panel have been completed. With increasing in impact energy, five types of damage patterns under the local punching failure mode appeared in turn. Comparing the residual deformation and the peak value of the membrane force, it could be concluded that reducing the spacing of tie bars improved the impact resistance of SC panels. The impact force-displacement curve of the drop hammer could be divided into five stages. Based on the dynamic response characterized curve and static loading test, a five-segment resistance function model for the entire process of impact response was proposed. The difference between the two failure modes of an SC panel under low-velocity impact reflected the different abilities to resist overall flexure failure and local punching failure. It also reflected the different method of energy dissipation. The criterion and formulas for distinguishing failure modes were proposed in this paper, and the calculation results were in good agreement with tests.