Effect of Interface Geometry on Strength of Single Lap Adhesive Joint of Sisal-Glass/Epoxy Laminates

Abstract

In this project, experimental work on tensile behaviour of single lap adhesive joints of sisal, glass and hybrid sisal-glass/epoxy composite laminates has been carried out. Composite laminates were fabricated by hand lay-up method using chopped strand mat sisal and glass fibers with epoxy resin matrix. Lab joints of four interface geometries; straight flat, triangular, rectangular and sinusoidal were fabricated. Tensile load-displacement relations were drawn and discussed. Effect of interface geometry and material type on maximum load and strength of the single lap joint was investigated. Failure mechanism of the fractured specimens was discussed. Results show that the glass/epoxy lap joints with semi-circular adhesive interface geometry supported load higher respectively 14.26%, 26.13%, and 30.79% than rectangular, triangular and straight flat interface geometries. Glass/epoxy lap joint with semi-circular interface geometry supported tensile load higher 5.61% and 21.83% than that obtained from hybrid sisal-glass and sisal/ epoxy adhesive joints. While the shear strength was found higher respectively 6.19% and 18.69%. Adhesive failure mode was observed for most of the single lap joints investigated. Mixed failure mode of adhesive and adherend materials was observed on the sisal/epoxy lap joints.