Blasting Resistance of Sandwich Bunkers with Carbon Fiber Reinforced Polymer Skins and Polymer Concrete Core

Abstract
The blast resistance of sandwich polymer concrete core bunkers (SPCB) with CFRP skins versus sandwich concrete core bunkers (SCB) is examined using ABAQUS/Explicit incorporating CONWEP feature. Investigation is conducted for varying TNT masses (1–25 kg), standoff distances (0.1–1 m), and core thicknesses (200–500 mm). Findings reveal that ABAQUS/Explicit with CONWEP accurately describes blasting behavior against existing laboratory and numerical results alongside the observation that increasing deflection, stress, and perforation damage correlate with higher blast masses, reduced distances, and thinner cores. SPCBs outperform SCBs, with the 500 mm thick SCB sustaining 34.8% more damage from a 25 kg TNT explosion at 1 m. SPCBs at 1 m demonstrate 80–99% greater performance while exhibiting superior blast resilience and seldom perforate compared to SCBs. From all results, robust regression equations for accurate predictions of principal and von Mises stresses based on core thickness, TNT mass, and standoff distance are established for future design convenience.