Behavior of three-dimensional woven carbon composites in single-bolt bearing

A comprehensive experimental evaluation of three-dimensional woven carbon composites arranged in various bolted bearing configurations is presented in this paper. Three unique three-dimensional woven fiber architectures were evaluated in single-bolt single-shear and double-shear configurations; two ply to ply angle interlock woven architectures were examined alongside an orthogonal woven architecture. All fiber architectures were woven with IM7 carbon in 12K and 24K tow sizes. To further enhance the understanding of these bolted connections, single-shear bolted joints were subjected to seven different loading orientations between the orthogonal warp and weft directions. Failure modes and fracture paths are analyzed and discussed for both single and double-shear experiments. Bearing strengths and stiffnesses for both single-shear and double-shear configurations were calculated and compared. Experimental results show that composites with three-dimensional woven fiber reinforcement exhibit exceptional strength when subjected to off-axis bearing loads despite the lack of off-axis reinforcement.