Multi-Criteria Analysis of Steel–Concrete–Steel Slab Performance: Dynamic Response Assessment Under Post-Fire Explosion

Steel–concrete–steel (SCS) composite slabs are widely used in critical infrastructures such as nuclear power plants, where systematic performance evaluation through multiple criteria is crucial due to their safety functions. During their use, fires may occur due to fuel or gas leaks, leading to explosions. This article uses ABAQUS 2020 finite element software and combines the different advantages of the implicit heat transfer algorithm and explosion display algorithm to establish a numerical simulation method for dynamic analysis of SCS slab under explosion after fire. Based on different fire conditions and the propagation laws of explosion shock waves, some key dynamic indicators and failure modes of the slab were studied. The results reveal progressive damage mechanisms with increasing fire duration, characterized by expanding damage areas, significant stress fluctuations, and increasing displacement rates. Additionally, the fire surface shows greater vulnerability than the back fire surface. The results provide multiple evaluation criteria for assessing structural performance, including temperature distribution, stress evolution, and damage patterns, which can support engineering decision-making in structural safety management.