Enhancing the flexural behavior of GFRP single‐lap co‐cure joints reinforced with multi‐reinforcements

Abstract The investigation focused on the glass fiber‐reinforced polymer (GFRP) composite co‐cure single lap joint (CC‐SLJ) that incorporates graphene nanoparticles (GNP) in epoxy and carbon fiber‐reinforced polymer (CFRP) Z‐pin reinforcement. The flexural test indicated that the integration of GNP and CFRP‐Z‐pin within the inner and outer layers of SLJ leads to improvement in flexural strength. The flexural strength of CC‐SLJ reinforced with GNP/epoxy and Z‐pin reinforcement reaches 145.02 MPa under static loading, with an improvement of 69.55% over the unreinforced SLJ. The SLJ under static loading with GNP/epoxy and graphene incorporated Z‐pin reinforced with demonstrate a significant improvement in flexural strength of 150.34 MPa, with an improvement of 71.22% over the unreinforced SLJ. Fractography revealed that the incorporation of GNP and Z pins into the SLJ enhances interfacial bonding between the adhesive and adherend, increases surface roughness, improves pin pull‐out resistance, and influences crack formation. Highlights The co‐cure technique is used to fabricate single‐lap GFRP composite joints. Carbon fiber‐reinforced polymer Z‐pin reinforced with GNP/epoxy adhesive. SLJ flexural strength was higher in 1.25 wt% of GNP and 2.5 vol% 90°/Z‐pin. Multiple reinforcements used in SLJ to achieve its maximum flexural strength. Failure analysis was conducted using microscopes and FESEM images.