Development of single-layer 3D ‘T’ profile with fillet for composite ‘T’ joints

This paper details about weaving of single-layer 3D ‘T’ profile with fillet for use as insert in composite ‘T’ joints and ‘T’ stiffeners. The ‘T’ insert with fillet was woven using 3 K carbon tows on a narrow width multi-beam automatic loom. Weaving was carried out based on the double-cloth weaving principle. Novelty of the work lied in the approach adopted for designing of the weave architecture in developing 3D ‘T’ profile with fillet portion, arriving at the pick cycle diagram for weave design development which has been detailed in this paper. Test results of composite ‘T’ joints fabricated incorporating the insert showed strength improvement as well as change in crack propagation mode as compared to conventional ‘T’ joint. The continuous insert with fillet acted as a bridging member among the three sections of the ‘T’ joint, thus contributing to performance improvement.