Numerical simulation of internal explosions in chambers using blast scaling laws

This study numerically investigates the application of blast scaling laws to internal explosions in chamber structures. The chamber consists of a steel/polyurea/aluminum foam/polyurea/steel laminated heterogeneous structure designed to improve deformation resistance through the combined action of heterogeneous layers. A coupled finite element method (FEM) and smoothed particle hydrodynamics (SPH) approach was validated against experiments, with prediction errors within 3.5% for wall deflections. Two scaling strategies, namely size scaling (SZ) and thickness scaling (TH), were adopted to investigate the influences of chamber scale and wall thickness on blast resistance behavior. The results indicated that, under a fixed scaled explosive distance, geometric enlargement significantly increased the side-wall deflection responses. However, the corresponding deflection ratio per unit weight did not increase proportionally and even decreased by approximately 7% in SZ-5, indicating a design trade-off between deflection amplification and structural mass increase. In contrast, the TH strategy effectively reduced structural deflection, but its deformation mitigation effect gradually saturated under high blast pressure. A preliminary engineering estimation relation was developed based on geometric scaling, incorporating explosive scaled distance and relative wall thickness. The results indicated that the side walls were the most sensitive components.