关键词: 平纹织物复合材料, 铺层复合材料, 织物结构, 裂纹扩展, 有限元分析

Abstract: With the increasing demand for high-performance composites, textile composites have been widely used in aerospace, rail transportation, automotive, and other fields due to their excellent in-plane and interlaminar properties and directional designability. However, with the integrated design and application of textile composites, it is crucial to further elucidate the mechanical properties and crack propagation resistance of textile composites at the micro and mesoscopic scales to further advance the application of this material.
Based on the above background, predicting the failure behaviour of composites is important for the structural design of composites. The paper explored the influence law of fabric structure on the mechanical properties of composites, especially to explore the crack propagation resistance mechanism,  established a unilateral crack composite model with different carbon fiber structures at mesoscopic scale using finite element analysis, and elucidated the characteristics and mechanisms of different carbon fiber structures in composites that contribute to its resistance against crack propagation through experimental verification with graphical deformation processing. The results show that the crack propagation energy density of the plain weave structure is 1.69 J/mm3, and that of the 0°/90° ply composites is 1.47 J/mm3, indicating a 15% increase in crack propagation resistance compared to the 0°/90° ply composites. The impact of unilateral cracking on the stress concentration behavior in textile composites was quantitatively assessed. The fracture strengths of the phenoxy resin board, 0°laminated composite, 0°/90° ply structure, and plain weave structure were found to be 31.1 MPa, 32.1 MPa, 249.5 MPa, and 346.1 MPa, respectively, with corresponding stress concentration coefficients of 2.6, 2.5, 12.1, and 7.6. Comparison of the finite element analysis with experimental results from non-contact full-field strain measurements further verifies the alignment between simulated and experimental trends in crack propagation. During crack propagation, the weft yarns in the plain weave composites experience a stress of approximately 700 MPa, whereas those in the 0°/90° ply composites endure a stress of roughly 150 MPa, indicating that the plain weave structure bears 4.67 times the load of the 0°/90° ply structure, and the plain structure with the undulating interlacing of the warp and weft yarns has an even better ability to resist the propagation of the cracks. At the same time, the stress distribution carried by the warp and weft yarns and the load transfer mechanism at the intersection of the warp and weft yarns were clarified, revealing that the one-piece fabric structure exhibits superior resistance to crack propagation.
Thus, the composite material model with fiber arrangement established in this paper predicts the crack propagation behavior of textile composites more accurately, and elaborates that the warp and weft yarn crossing structure has a good crack propagation resistance, and thus may provide a method and reference for the structural optimization design of textile composites.

Key words: plain weave fabric composite, laminated composite material, fabric structure, crack propagation, finite element analysis