Multiscale modeling and tensile behavior analysis of uniaxial reinforced warp‐knitted composites

A parameterized unit cell model of uniaxial reinforced warp‐knitted composites is established through Python programs. The knitting yarns in tricot organization and the Stich Yarn induced fiber Distortions (SYDs) are considered in the model. The phenomenon of uneven fiber content around the SYD areas is described using a hierarchical multiscale model. Longitudinal tensile experiments are performed on this material, and the results are consistent with the numerical prediction. The initial damage is mainly caused by the fiber fracture near the SYD areas, and the matrix between reinforcing yarns tends to crack along the fiber direction. The binding function of knitting yarns in the manufacturing process is highlighted through a failure mechanism comparison with the traditional uniaxial reinforced composites. The parameter analysis indicates that the content of knitting yarns has negative effects on the tensile properties of the material. In addition, the layer thickness has a positive effect on the longitudinal tensile stiffness and strength. These findings can be valuable guides for structural design and manufacture of warp‐knitted composites. POLYM. COMPOS., 40:2510–2522, 2019. © 2018 Society of Plastics Engineers