Experimental Investigation of Adhesively Bonded Single Lap Joint in Nautical Applications

This chapter delves into the experimental investigation of adhesively bonded single lap joints (SLJ) in nautical applications, focusing on their strength, failure modes, and the impact of adhesive properties. The study employs Crystic621 adhesive, a pre-accelerated orthophthalic polyester resin, to bond GFRP (Glass Fiber Reinforced Polymer) adherents, commonly used in marine environments for their lightweight and corrosion-resistant properties. Through tensile tests and Digital Image Correlation (DIC) analysis, the research examines the mechanical behavior of the adhesive and the SLJ specimens under uniaxial tensile loads. Key findings include the observation that the tensile stress of the adhesive is approximately 20.5 MPa, independent of the specimen's thickness, while the Young modulus decreases with increasing thickness. The SLJ load-displacement curve reveals that damage initiates quickly but failure occurs at a load of 3 kN and a displacement of about 4 mm. Macro-scale analysis and DIC observations highlight that the crack initiates at the joint extremities, classified as a cohesive failure with low substrate pull-out. The study concludes by emphasizing the importance of adhesive selection and surface preparation in enhancing joint performance and durability. Additionally, it suggests future research directions, such as investigating the influence of surface roughness on joint strength and exploring different joint configurations to better understand their impact on failure modes.