Experimental research and finite element analysis on blast resistance of RRACFST columns

In order to research the dynamic response of rectangular recycled aggregate concrete-filled steel tubular (RRACFST) columns under blast loads, three contact blast experiments were carried out on three column models, and their different failure modes, dynamic strain rates and acceleration rates were determined. The numerical model was established using the arbitrary Lagrangian-Eulerian method and the fluid–solid coupling algorithm available in the explicit nonlinear finite element software LS-DYNA™, and the reliability and validity of the numerical model were verified by the experimental results. On this basis, the numerical model was used to analyze the parameters, as well as the effects of the replacement rate of recycled aggregate, column height, steel tube thickness and steel strength on the contact explosion resistance of RRACFST columns. Also, the advantages and disadvantages of overall refinement and local refinement are compared. The study results show that the RRACFST columns had basically no overall response to the action of contact blast loads, producing only a small explosion crater in the detonation area, without breaking the steel tube, and with no recycled aggregate concrete (RAC) overflows. The steel tube thickness was the decisive factor affecting the blast resistance performance of the RRACFST columns. In addition, for the numerical simulation of contact explosion, the local refinement was better than the overall refinement.