Secondary bonded and co-bonded CFRP composite joints with innovative lamination technique: Flexural and failure analysis

Abstract

Adhesively bonded techniques effectively fuse the structural components in an assembly in aerospace applications. The co-bonding is more effective than secondary bonding for joining fuselage frames to skins, wing ribs, and spars to skin joints. The flexural behavior and failure analysis of a carbon fiber-reinforced polymer composite single-lap joint is one crucial factor in aerospace applications. This research involved the fabrication of co-bonded carbon fiber-reinforced polymer composite single-lap joints utilizing the vacuum bag hand lay-up method, incorporating geometric modification techniques, including interleaved and covered lamination. The flexural strength was examined through a three-point bending test. The results indicate that the secondary bonded with covered lamination techniques has attained the maximum flexural strength compared to others. The values are 80% higher than the neat secondary bonded joints. Moreover, the carbon fiber-reinforced polymer composite single lap joint samples were examined for failure analysis using the ASTM D5573 standard. Furthermore, these geometric modifications in CFRP composite joints confirmed the significant enhancement in experimental results with less than 5% error rates. Highlights: Carbon fiber-reinforced polymeric (CFRP) joints were made utilizing interleaved and covered lamination methods. SB and CB methods were utilized to fabricate the CFRP composite joints. CL-SBT exhibits high flexural strength (639 MPa) and modulus (45.94 GPa). A thin-layer cohesive failure was observed in interleaved CFRP joints, The fiber tear failure was observed in covered lamination CFRP joints.