Failure analysis in an adhesively bonded single-lap composite joint under various loads

In this study adhesively bonded composite single-lap joints are investigated experimentally. Different surface properties, different curing temperatures of the adhesive, and the effects of different adhesive thickness on the composite joint strength are investigated. First, mechanical properties of the adhesive and adherend are investigated. Then tensile tests, axial impact tests, transverse impact tests and four point bending tests are conducted, respectively. All of these test are made in different conditions like operation temperature, surface quality, curing time, impact energy etc. Finally, after these series of the tests, for having good strength in different conditions, joint modifications are studied and some configurations are made on the composite joint and tested. This study showed that adhesive thickness, curing temperature, surface quality, operation temperature and impact energies have an important effect on the composite joints. Generally these effects were adverse but in some conditions these effects were useful. Additionally to the failure analysis, in this study, we used these useful effects to modify composite joints and we developed high strength composite joints in higher operation temperatures.