In‐plane shear behaviors of unbalanced 3D interlock woven reinforcement in bias extension test: Experiments and finite element modeling

Abstract In this paper, the in‐plane shear deformation of unbalanced 3D interlock woven reinforcement (IWR) was investigated through experiments and finite element modeling. Five specimens with five layers warp (six layers weft) were designed and prepared. The warp is 792 tex carbon tows and weft is 396 tex carbon tows. This kind of reinforcement is unbalanced because that the linear density of warp is different from that of weft. The in‐plane shear deformation of unbalanced 3D IWR was tested by bias extension test. The bias extension process was simulated by finite element method from macro and meso scales. The results of simulation are basically consistent with experiments. The bias extension process can be divided into three stages: Meso scale deformation stage, multiscale deformation stage and Reinforcement failure stage. At meso scale deformation stage, the tensile load and shear angle are small when the displacement is less than 7.5 mm. There is no obvious change in the macro scale, while the weft slipping in the meso scale mainly occurs in area B. The deformation of B1 and B2 are asymmetric because the linear density of warp is different from that of weft. In the multiscale deformation stage, asymmetric deformation at the macro scale begins to appear when the displacement is between 7.5 mm and 20 mm. There is obvious in‐plane shear deformation in area C at the meso scale. In the reinforcement failure stage, A large number of weft yarns are pulled out from the reinforcement in area B.