Penetration resistance of fiber-reinforced basic magnesium sulfate concrete: Experimental and numerical investigations

• Penetration depth in FRBMSC rises markedly with projectile velocity but is effectively mitigated by fiber reinforcement. • Incorporating 2 vol% fibers cuts penetration depth by over 30% at 200 m/s. • Raising fiber content to 3 vol% yields only marginal additional benefit, pinpointing 2 vol% as optimal. • Mesoscale simulations uncover linear and power-law dependencies and underpin a predictive penetration-depth model. Basic magnesium sulfate cement offers significant potential for protective engineering due to its high strength and toughness. Understanding the penetration resistance of fiber-reinforced BMSC (FRBMSC) under high-velocity impact is crucial for such applications. This study aims to systematically investigate the ballistic penetration resistance of FRBMSC, elucidate its failure mechanisms under high-strain-rate loading, and develop a predictive model for penetration depth. Ballistic penetration experiments and mesoscopic numerical simulations were employed to assess FRBMSC performance against projectile impact. The penetration depth increased significantly with the initial projectile velocity but was substantially mitigated by fiber incorporation. This reduction was most pronounced at fiber contents between 0% and 1%, and became more gradual from 1% to 3%. Regarding crater morphology, the crater size was significantly reduced as the fiber content increased from 1% to 2%, with only marginal further improvement at 3%. Based on an integrated analysis of penetration depth and crater dimensions, it is recommended that a fiber content of 2% be used for FRBMSC. Furthermore, mesoscale simulations revealed quantitative correlations: the penetration depth exhibited power-law dependencies on projectile mass, velocity, and shape factor. The study successfully identified the optimal fiber dosage for enhancing FRBMSC’s penetration resistance and established quantitative relationships between projectile parameters and penetration depth. Based on these findings, a predictive model was developed, enabling accurate estimation of penetration depth across varying impact scenarios, which advances the application of FRBMSC in protective structures.