Study on the dynamic response of concrete open-web sandwich plate under close-range blast loading based on the CEL method

A novel large-span floor system called concrete open-web sandwich plate (COSP) has been studied recently due to its apparent advantages in reducing self-weight, high stiffness, and convenience for installing equipment pipelines. To investigate the dynamic response of COSP under close-range blast loading, a series of finite element models of COSP have been developed based on the Coupled Eulerian-Lagrangian (CEL) method. The influences of four parameters, including TNT masses, blast height, shear key width, and charge shapes, on the dynamic responses of COSP are systematically investigated. The results show that: (1) The damage degree of the COSP decreases as the blast height increases when the TNT mass remains constant and increases as the mass of explosives rises when the blast height remains constant. Moreover, the maximum vertical displacement of the center of the COSP is positively correlated with the mass of explosives, such that doubling the quality results in a 30-100 % increase in maximum displacement. In most cases, the increase is around 100 %. (2) The top and bottom ribs of COSP, along with the local bending moment of the shear key, significantly influence the overall displacement response. Widening the shear key can reduce the dynamic response of COSP and improve its stability. (3) Variations in Mises stresses are observed in the reinforcement of the COSP under different TNT masses and charge shapes (cube, sphere, cylinder, and rectangular) and arrangements (axial and radial). The bottom rib's lower layer experiences higher stresses than the upper layer, while the upper layer of the top rib undergoes higher stresses than the lower layer. (4) The displacement response and damage ranking of the COSP following explosions with different charge shapes and arrangements are as follows: cylinder radial > rectangular radial > cube > sphere > rectangular axial > cylinder axial.