Non-crimp fabric composites

A non‐crimp fabric mechanical characterization for the production of aerospace components

“…10 Lomov has made a fundamental contribution to the understanding, design, and implementation of the NCF. [11][12][13][14] Damage on non-crimp fabrics composites loaded in tension has been investigated by Edgren. 15 The damage mechanism has also been studied for non-crimp laminates subject to fatigue using digital image correlation 16 and for bolted joint NCF both experimentally and by FE modelling.…”

Evaluation of adhesive binders for the development of yarn bonding for new stitch-free non-crimp fabrics

“…Also NCFs show better mechanical properties (strength, Young’s modulus, degree of drape), flexibility in design and low production cost compared with the most widely used woven fabrics. 4,5 They can be used for the composite production process (VARI, RTM, etc.). Multi-axial warp-knitted fabrics are currently used in a wide variety of application areas, such as construction of automobiles, aerospace components, geo textiles, vessel body parts and pneumatic materials.…”

“…The mechanical properties of the composites made of NCF are affected by the quality of the textile reinforcement. For example, Airbus Industry Material Specifications (AIMS) define and quantify different defects of NCF, 4 for example crease or wrinkle, cut or tear (adjacent yarn is cut or broken), yarn splice (broken or severed yarn, which is rejoined), fuzz ball (accumulation of loose or frayed fibers within fabric or on the surface), gap (open space between parallel fibers or between the filaments), missing knitting loop, incorrect fiber orientation and missing reinforcement yarn. In addition to the possibility of the introduction of these defects, the current production process for NCFs through stitching results in several major drawbacks.…”

“…Stitching causes distortions of the fiber orientation in the fibrous mat. 4 Also, it leads to a displacement of parallel fibers, resulting in gaps or openings. 6–8 The tension of the warp-knitting yarn may lead to the local compaction of the reinforcement fiber bundles, resulting in gaps and so-called “fish eyes” in the fabric that in turn lead to matrix-rich parts in the composite, also resulting in a degradation of mechanical properties.…”

“…6–8 The tension of the warp-knitting yarn may lead to the local compaction of the reinforcement fiber bundles, resulting in gaps and so-called “fish eyes” in the fabric that in turn lead to matrix-rich parts in the composite, also resulting in a degradation of mechanical properties. 4,9 Furthermore, the yarns face damages by means of the stitching needles, which in most cases pierce through the individual reinforcement yarns. The mechanical characteristics of the composites are affected negatively in both cases, which results in a decrease of strength of the composite materials by up to 40%.…”