Abstract:
The fiber structure of 3D stitched composites is complex and the microstructure of stitched area is uncertain. A virtual fibre modelling method for 3D stitched composites was proposed to generate a high-fidelity geometric twin model of the stitched position by simulating the stitching manufacturing process. Micro-CT technique was used to analyze the fiber structure of the stitched position, and the accuracy of the geometric twin model was verified. Considering the uncertainty of the stitching structure, four representative geometrical structures were proposed, four-cell models of 3D stitched composites were constructed using virtual fiber embedded (VFE) method, in which the virtual fiber structures were embedded into voxel elements representing matrix material. Damage models were established for fiber and matrix materials to simulate the tensile damage process of 3D stitched composites, and the mechanical properties of different stitched positions were predicted. The average values of the predicted results of the four-cell models are consistent with the experimental results, and the prediction errors of tensile strength, modulus and damage strain are 1.5%, 1.2% and 0.4%, respectively.