Investigation on the damage features and dynamic response of reinforced concrete slabs with polyurethane sacrificial cladding under close-range explosions

Sacrificial cladding has been widely used in the blast mitigation and protection of engineering structures, and its protection performance and mechanism have also attracted the extensive research interest of scholars. In order to study the blast damage mitigation effect of polyurethane (PU) sacrificial cladding on reinforced concrete structures, close-range explosion tests of the reinforced concrete slabs with polyurethane sacrificial cladding (PU-RCS) were carried out. At the same time, the reinforced concrete slabs (RCS) without polyurethane sacrificial cladding were set as the control group, and the influence of sacrificial cladding on the damage mode of the reinforced concrete slab was compared and analyzed. In addition, the SPH-FEM coupling model corresponding to the field explosion test was developed and verified by comparison with the test results. On this basis, numerical simulation analysis was used to investigate the dynamic response process of PU-RCS. Furthermore, the effects of the explosive charge and the thickness of polyurethane sacrificial cladding on the damage features of PU-RCS. Based on a large number of numerical simulation analyses, the prediction formula for the mid-span displacement of PU-RCS was proposed. The results show that under close-range explosion, the polyurethane sacrificial cladding can effectively disperse the blast loads, change the damage mode of the reinforced concrete slab, and demonstrate good mitigation ability. The proposed prediction formula can well predict the mid-span displacement of PU-RCS.