Investigation on the effects of fiber orientation and resin content on the mechanical properties of basalt fiber/vinyl composite laminates

To clarify the effects of fiber orientation (FO) and resin content (RC) on the mechanical properties of basalt fiber reinforced polymer (BFRP) composites, a full factorial experimental design was employed. Fiber orientations of 0°, ±45°, and 0/90°, together with resin contents of 40 wt.%, 50 wt.%, and 60 wt.%, were selected as the main variables. Nine groups of BFRP laminates were fabricated via hand layup, followed by tensile, flexural, interlaminar shear, and impact tests. The contribution degrees of each factor were analyzed using the two-factor analysis of variance method. The results demonstrate that fiber orientation determines the load transfer efficiency and anisotropy of composites. Proper alignment along the loading direction significantly improves mechanical properties. Tensile strength is primarily dominated by fiber orientation. At a resin content of 50 wt.%, the tensile strengths of 0°, ±45°, and 0/90° laminates are 151 MPa, 119 MPa, and 286 MPa, respectively. Resin content dominates interfacial bonding and internal defects. An optimal resin volume fraction ensures sufficient wetting and strong interfacial adhesion, leading to the best mechanical performance. Resin content significantly affects flexural strength, interlaminar shear strength (ILSS), and impact performance. The tensile, bending and impact properties are influenced by the coupling effect of fiber orientation and resin content. Microstructural observations reveal that the dominant damage mechanisms include interfacial debonding, fiber pull out, and matrix cracking. At the same time, a regression model was established to conduct a thoroughness test on the experimental results. The fitting effect is excellent.