Mesoscale model for elastic modulus of warp-knitted fabric-reinforced composites based on spring model

In this paper, a ‘mesoscale spring model’ was generated to predict the tensile modulus of warp-knitted fabric-reinforced composites. A previously developed geometrical model was used for generating a mechanical model as a set of series and parallel springs. For this purpose, the unit cell of straight line model was discretized into different segments. Each segment was modelled as a spring with definite constant based on the alignment of yarns in the segment. Warp-knitted fabrics (Queen's Cord) were used as reinforcement of composites. In order to validate the presented model, samples of composites were produced using hand layup method. Tensile tests were carried out on the prepared samples. The comparison between theoretical and experimental elastic modulus showed a reasonable agreement between experimental and theoretical data. Also, the comparison between the results of different models and experimental data showed that the results of spring model are closer to the experimental results than that of Krenchel's model. It can be concluded that the spring model can predict adequately the elastic modulus of composites.