Needling model for predicting mechanical behaviours of waste cotton composites

Abstract

Three-dimensional (3D) waste short fibre reinforced needle-punched composites (3DNPCs) have many application scenarios in the civil engineering field due to their low-cost technology and excellent interlaminar properties. This work first proposed a mesoscopic scale model by the random sequential algorithm to investigate the influence of the fibre structure on the open-hole tensile mechanical properties of 3DNPCs. The reconstruction model was composed of the microstructural model and the homogeneous model, both of which take the needle-punched structure into consideration. The results show that the homogeneous model considering the needling structure is more consistent with the experimental results in the thickness direction than the traditional 2D random model. Compared with the open-hole tensile experimental results, the reconstruction model with a larger hole size could significantly increase the initial stress concentration area and crack size around the hole. The needling fibres in the meso‑model enhanced the mechanical properties in the through-thickness direction and played a secondary role in open-hole stretching, preventing failure in the plastic stage. The proposed computational framework can be extended for predicting the mechanical behaviours of 3D waste short fibre reinforced needle-punched composites.