Abstract:

A series of specimens were fabricated by using a single lap adhesive connection of aramid fiber composite material with titanium alloy, and the ultimate load, stress field strain distribution and failure mode of the bonded joints were characterized with a universal testing machine, DIC and strain acquisition system. The strain distribution of bonded joints under tensile load and the stiffness reduction law of composite laminates were analyzed. Moreover, the failure process of single lap adhesive joints of dissimilar materials was also studied. The results indicated that the failure modes of bonded joints were ascribed to the adhesive interfacial failure at the two ends of overlap region and the composite delamination failure in the middle part. When the joint was under the load, the composite end was subject to the large shear strain, which led to the cracks occurring at the composite end and then continuously expanding to the metal end. The entire failure process of the joint belongs to a progressive failure. The stiffness of composite was continuously reduced with the propagation of cracks until the adhesive failure suddenly took place due to the small area.

Key words: singe lap joint, bonded joint, cohesive failure, progressive failure