A hyperelastic constitutive model accounting for tension-shear coupling in preforming modelling of 3D woven fabrics

The accurate preforming modelling of 3D woven fabrics is essential for their forming quality control and optimization. However, their tension-shear coupling during preforming is not considered in the existing models. To address this issue, an anisotropic hyperelastic constitutive model considering the tension-shear coupling was established for 3D woven fabrics. A picture frame tester was designed and manufactured to investigate tension-shear coupling effect. The results show that the fiber pre-tension can significantly enhance the shear resistance of 3D woven fabrics. The biaxial pre-tension of 1.5 % can increase the in-plane shear force by up to 2.25 times compared to that in the pure in-plane shear. The identified tension-shear coupling parameters were integrated into the hyperelastic constitutive model and were implemented via user subroutine in Abaqus. The model's effectiveness was verified by the hemispherical and fan blade forming experiments. The proposed coupled model demonstrates higher prediction accuracy than the uncoupled model in terms of shear angle and force, which provides a valuable tool for the optimization of forming process of 3D woven fabric.