STATIC AND FATIGUE BEHAVIOR OF ADHESIVE JOINTS IN SMC-SMC COMPOSITES

This paper discusses the static and fatigue behavior of adhesively bon ded single lap joints in SMC-SMC composites. Effects of lap length and adhesive thickness on the static and fatigue strength of SMC-SMC adhe sive joints are studied. Effects of SMC surface preparation and test s peed on the joint performance are evaluated. Finally, the effect of wa ter exposure on the joint durability is also investigated. Results sho w that the static behavior of adhesive joints in SMC-SMC composites is significantly influenced by the lap length and adhesive thickness. Wi th an increase in lap length from 12.7 mm to 38.1 mm, the joint failur e load increases by 37% The joint failure load also increases with the adhesive thickness, but it reaches a maximum at an adhesive thickness of 0.33 mm and then decreases. However, lap length and adhesive thick ness have negligible effect on the ratio of fatigue strength to static strength. The fatigue strength at 10(6) cycles is approximately 50% t o 54% of the static strength for various adhesive thicknesses and lap lengths investigated in this study. Adhesive failure, fiber tear or co mbination of these two failure modes are observed during both static a nd fatigue tests.