Research on the numerical simulation of dynamic explosion shock wave propagation characteristics between floors

This study addresses the assessment of dynamic explosive shock wave loads in building damage evaluation. Utilizing numerical simulation methods, we investigated the propagation process of shock waves between building floors, capturing the evolution of their wavefronts. We particularly focused on discussing the variation patterns of pressure peaks caused by vertical shock wave reflections. Computational analysis indicates that under static conditions, inter-floor explosive shock wave overpressure peaks are significantly stronger than those from free-field explosions. Specifically, within a distance range of 2–3 m/kg1/3, the overpressure peak from inter-floor explosions is approximately three times greater than that from free-field explosions. In scenarios involving an equivalent charge of 400 kg and initial velocities ranging up to 1200 m/s, it was observed that shock waves propagate as partially spherical wavefronts within a distance of 15 m between floors; beyond this range, they evolve into nearly planar wavefront propagation. Within this 15 m range, constraints imposed by floor slabs lead to non-uniform and continuously varying vertical pressure distributions. After two reflections, the vertical pressure distribution approaches uniformity. For cylindrical charges, the characteristics of vertical distribution changes in shock waves can be categorized into four stages (while spherical charges correspond to three characteristic stages). The intensity of these variations is primarily influenced by the initial velocity of the explosion source and shows insensitivity toward both the length–diameter ratio and equivalence weight of the charge. Moreover, a model capable of assessing this pressure non-uniformity feature has been established in this paper, which can estimate the pressure distribution characteristics under different initial velocity circumstances rather rapidly and accurately.