Bending deformation of composite fabrics is a critical factor in wrinkle formation during forming processes and bending stiffness values are essential for the precision of simulation results. However, the bending stiffness of fabrics is not only closely related to their textile architecture but also exhibits significant nonlinear characteristics. In this study, a characterization method for bending stiffness determination is achieved via constrained fitting of the fabric’s deflection curve. Furthermore, based on this characterization method and the definition of linearity rate, the influence of fabric structure on bending stiffness is investigated. The results demonstrate that increased structural complexity in fabrics generally leads to higher bending stiffness and lower linearity rate. The bending stiffness of fabrics tufted along the length direction is at least 30% higher than that along the width direction. In addition, stitched fabrics exhibit a bending stiffness about three times greater than that of tufted fabrics. Finally, simulation analyses reveal that when the linearity rate is lower than 0.26, the use of nonlinear bending stiffness helps improve the accuracy of simulation results.
Zhang et al. (Tue,) studied this question.