Investigating the synergistic effects of geometric (interleaved lamina) and adhesive modifications on the shear behavior of co-cured CFRP composite joint: Prediction and optimization using statistical and deep learning approach

• CFRP composite joints fabricated using the interleaved lamina technique. • Three techniques were implemented to improve the shear strength of CFRP joints. • At 0.75 wt.% MWCNT modified adhesive, CFRP joints can reach 18.9 MPa. • The co-curing technique has enhanced interfacial chemical and diffusion bonding. • Cohesive failure was observed in interleaved lamina with co-cured CFRP joints. Co-curing is an effective bonding method essential for the adhesion of both homogeneous and heterogeneous materials in aerospace, aviation, and marine contexts. The shear strength of an adhesive-bonded single-lap joint is the primary property of interest. This study examines the shear strength of co-cured CFRP composite joints fabricated via the interleaved lamina technique using multi-walled carbon nanotube (MWCNT) modified adhesive. The experimental findings demonstrated that incorporating 0.75 wt.% MWCNT-modified adhesive into the interleaved lamina of a co-cured CFRP composite joint resulted in a shear strength of 18.9 MPa. This value signifies a substantial increase of 19% in comparison to the pure epoxy-based interleaved lamina with co-cured CFRP composite joint and an impressive 60% increase relative to the neat co-cured CFRP composite joint. The practical implications of these findings are significant, as they can enhance the performance and reliability of structures in various applications. The ANOVA analysis of the experimental results further confirmed the statistical significance with a less than 5 % error rate, providing a high confidence level in the research findings and reassuring the audience about the reliability of the results. The shear performance was precisely forecasted utilising the Levenberg-Marquardt artificial neural network model and refined via the least squares fitting technique.