Predictions of first-ply failure load of laminated composite shafts

The failure strengths of laminated composite shafts subjected to static bending load and/or torque are studied using both theoretical and experimental approaches. We investigate optimal angle-ply orientations of laminated composite shafts with the design of symmetric main fiber lay-ups [θ/−θ/...] S and anti-symmetric reinforcing fiber lay-ups [α/−α/...]−S for maximum stiffness. Different analytical methods, together with various failure criteria, are used to predict the first-ply failure strengths of the composite shafts. A hand lay-up and pressure bag technique was used to manufacture the composite shafts, which includes the stacking of pieces of prepreg in the desired orientations and the curing process. The first-ply failure loads of laminated composite shafts were determined using acoustic emission. The failure modes of the shafts are studied and experimental results are used to verify the theoretical predictions. The experimental results have been proven to be efficient and effective in the theoretical prediction of first-ply failure loads of laminated composite shafts.