Ar$\chi$i-Textile Composites: Role of Weave Architecture on Mode-I Fracture Toughness in Woven Composites

This paper investigates the impact of weave architectures on the mechanics of crack propagation in fiber-reinforced woven polymer composites under quasi-static loading. Woven composites consist of fabrics containing fibers interwoven at 0 degrees (warp) and 90 degrees (weft) bound by a polymer matrix. The mechanical properties can be tuned by weaving fiber bundles with single or multiple materials in various patterns or architectures. Although the effects of uniform weave architectures, like plain, twill, satin, etc. on in-plane modulus and fracture toughness have been studied, the influence of patterned weaves consisting of a combination of sub-patterns, that is, architected weaves, on these behaviors is not understood. We focus on identifying the mechanisms affecting crack path tortuosity and propagation rate in architected weave composites containing various sub-patterns. Through compact tension tests, we determine how architected weave patterns compared to uniform weaves influence mode-I fracture toughness of woven composites due to interactions of different failure modes. Results show that fracture toughness increases at transition regions between sub-patterns in architected weave composites, with more tortuous crack propagation and higher resistance to crack growth than uniform weave composites. We also introduce three geometrical parameters transition, area, and skewness factors to characterize sub-patterns and their effects on in-plane fracture toughness. This knowledge can be exploited to design and fabricate safer lightweight structures for marine and aerospace sectors with enhanced damage tolerance under extreme loads.