Assessment of the impact of different weave geometries on the crimp factor of woven preforms made from high-performance carbon filaments

Crimp, also known as fabric waviness, is a key factor affecting weaving efficiency and the performance characteristics of woven fabrics, especially high-performance fabrics. Increased crimp typically enhances yarn interlocking, thereby improving the structural stability of the fabric. The added friction between yarns boosts resistance to distortion and slippage, which is crucial for maintaining the fabric's shape during use and subsequent processing. However, excessive crimp can reduce the mechanical symmetry of the fabric and, in demanding applications such as composite materials, compromise its dimensional stability under stress. Producing composite preforms with minimal crimp while ensuring improved structural integrity remains a significant challenge. Crimp levels can be adjusted by employing different weave patterns while keeping the fabric-making parameters constant. In high-performance applications like composites, the reduced crimp is preferred for better load distribution and material strength, making non-crimp woven textiles a favorable option. Advanced automated processes are typically employed to produce non-crimp woven preforms, including three-dimensional (3D) woven preforms with three sets of interlocked yarns or uni-directional woven preforms. This research uses conventional two-dimensional (2D) weaving techniques to fabricate high-performance composite materials. Experimental studies were conducted on various basic weave patterns to produce high-performance carbon woven preforms using advanced 2D weaving machines (Dobby shedding). The findings demonstrate that the weave design significantly influences the crimp in carbon woven preforms. The crimp percentage (C%) was calculated as the ratio of the un-crimped length of the tow to its crimped length. The study revealed that the crimp in both warp and weft tows of the woven preform varies notably based on the weave design.