Elastic properties prediction of a knitted composite with inlaid yarns subjected to stretching: A coupled semi-analytical model

Knit reinforced composites cover a large range of mechanical properties thanks to the multitude of structures available. In this paper, a semi-analytical tool is presented allowing to improve the fabric design by assessing the elastic properties of a stretched knit reinforced composite with several inlays. The stretched loop geometry is obtained with a loop stretching model based on the beam theory. A geometric model of the inlays is proposed. These results are used as input data of a mesoscopic scale homogenisation model to assess the composite elastic properties. A comparison of the results to the load-strain curve of a plain knit shows that the modelled loop shape is realistic, and the homogenisation model results agree with experimental data. This tool is used to draw a map of the wale-wise versus course-wise modulus that can help to design a fabric leading to a composite with tailor-made properties.