Influence of S-Glass and E-Glass Hybridization on the Mechanical Properties of Epoxy-Based Composite Laminates

The aim of this study is to investigate the mechanical performance of S-glass and E-glass fiber-reinforced epoxy composites manufactured using the hand-layup technique with epoxy resin (Lapox L-12) and hardener (K-6), cured for 24 h at room temperature. To investigate the effect of different configurations, six configurations were tested: pure S-glass/epoxy (Sc-E), pure E-glass/epoxy (Ec-E), and four combinations of S-glass/E-glass at different stacking sequences (1Hc-E, 2Hc-E, 3Hc-E, and 4Hc-E). All composites were fabricated with 60 wt% fiber and 40 wt% matrix. Mechanical characterization comprised tensile testing (crosshead speed 10 mm/min), three-point bending tests for flexural properties (5 mm/min), interlaminar shear strength (ILSS) testing (3 mm/min), and Shore D and Barcol hardness testing. The results showed that the ultimate tensile strength (188.42 MPa) and Young’s modulus (1.60 GPa) were highest for the Ec-E sample, while the peak load (8903.02 N) was highest for the Ec-E sample. For flexural properties, the 1Hc-E hybrid configuration (ss-ee-ss-ee) exhibited an excellent flexural strength of 416.60 MPa and a flexural modulus of 26.08 GPa, indicating a positive hybrid effect. The pure S-glass composites showed the best ILSS (16.52 MPa) and hardness properties. The study revealed that flexural properties can be optimized through strategic hybridization and that fiber stacking sequence has a significant effect on interlaminar properties.