Influence of crimp on 3D-woven fibre reinforced composites

Three analytical models are developed for prediction of the longitudinal Young’s modulus of carbon fibre composite materials containing fully interlaced 3D-woven textile reinforcement. Two of the non-linear models utilise rods and springs and are designed to handle an idealised periodic repetitive volume element of the composite material. For validation, an experimental study is performed, and a more detailed model is built using existing textile software (TexGen and WiseTex). All models are employed to explore the effect of three-dimensional yarn crimp on the longitudinal Young’s modulus, and they give at hand that the longitudinal stiffness decreases non-linearly with increasing crimp. One of the proposed models agrees particularly well with the experimental results but there are also a few sources of discrepancy, such as shape distortions in the textile architecture.