Comparison of shear strength tests on AV119 epoxy-joined carbon/carbon composites

The results of an experimental investigation on carbon/carbon composites (C/C) bonded joints tested in shear at room temperature, under seven different configurations, are presented. The samples have been joined by an epoxy adhesive (AV119): this adhesive is not to be considered as a suitable joining material for C/C for high temperature applications, but just as a model joining material chosen to obtain several bonded samples in a short time. Advantages and disadvantages of each configuration are discussed from an experimental point of view. A finite element analysis is also performed to compare the stress distribution obtained within the joint for the different testing geometries. It is shown that the measured values of the apparent shear strength decrease with the maximum opening stress estimated within the middle of the joint.