This study investigates the mechanical performance enhancement of e-glass/basalt fiber reinforced polymer (FRP) sandwich composites through boron carbide (B4C) nanoparticle modification for marine structural applications. The research focuses on developing lightweight, corrosion-resistant composite panels capable of withstanding harsh marine environments while maintaining structural integrity. Three different B4C concentrations (0.6%, 1.0%, and 1.4% by weight) were incorporated into epoxy resin matrices, which were then used to fabricate sandwich panels with varying fiber orientation sequences ([0°/90°], [±45°], and quasi-isotropic layups). The composite structures were evaluated through comprehensive mechanical testing including tensile, flexural, impact, and water absorption tests following ASTM standards.

Finite element analysis (FEA) was performed using ANSYS ACP to simulate stress distribution under hydrostatic pressure conditions representative of underwater applications. Experimental results demonstrated that the 1.0% B4C reinforced quasi-isotropic samples exhibited optimal performance, showing a 27.3% increase in flexural strength (from 412 MPa to 524 MPa) and 18.7% improvement in impact resistance compared to control samples. Water absorption tests revealed a significant reduction (up to 35%) in moisture uptake for B4C-modified specimens. Microstructural analysis using SEM confirmed improved fiber-matrix interfacial bonding in nanoparticle-enhanced samples.

These findings suggest that judicious incorporation of B4C nanoparticles in e-glass/basalt hybrid sandwich structures can substantially enhance mechanical properties while providing excellent moisture resistance, making them suitable for marine applications such as boat hulls, offshore platform components, and underwater vehicle structures. The study provides a framework for optimizing nanoparticle-reinforced hybrid composites for demanding marine environments.