Delamination prevention of composite joints with asymmetric carbon-fiber reinforced plastic adherends

Abstract

The use of adhesive bonding in aeronautical applications has gained popularity due to its numerous advantages over traditional mechanical fastening methods. However, the issue of delamination still poses a significant challenge in fully embracing this technology in the industry. This study proposes a unique approach to optimize carbon fiber reinforced polymer (CFRP) single lap joints (SLJ) by introducing a curved joint design with varying adhesive thickness. The curvature is achieved through the intentional warpage caused by residual stresses resulting from an asymmetrical composite layup. While these residual stresses can potentially lead to cracks and distortions, this research aims to leverage their presence to enhance joint performance and mitigate delamination risks. A comprehensive analysis, involving both numerical simulations and experimental testing was conducted to compare the performance of the curved joint design with traditional configurations. The findings indicate that the curved joint design effectively prevents delamination while maintaining comparable joint strength. This demonstrates the potential benefits of employing curved joints for aeronautical components with curved geometries, affirming the feasibility and advantages of this approach. However, further optimization of the curved joint configuration is warranted to enhance its performance and expand its applicability to a broader range of applications.