Study on the in-plane shear performance of spacer fabrics in composite forming

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IMPOL Slovenska bistrica
Shear properties are important not only for standard fabrics but for textile-reinforced composites as well. Shear is one of the most common flaws that occurs during textile-composite-reinforcement forming processes. To ensure the production of high-quality textile-fabric-reinforced composites when forming complex shapes, the potential for an in-plane deformation of the fabric reinforcement must be taken into consideration. This research paper will present the emerging textile fabric of this decade, commonly known as the 3D spacer fabric, which could be used as the reinforcement for complex-shaped composites. The objective of this research was to study the shear behavior of 3D knitted spacer fabrics using a picture-frame fixture. The images acquired during the loading process were used for an analysis in order to obtain a full-field displacement and shear angles at the chosen points on the surface of a test specimen. To determine its suitability for measuring the in-plane shear properties of the 3D knitted spacer fabrics, experimental and analytical investigations of the picture-frame shear fixture were conducted. The non-linear behavior of the shear force versus the shear angle and deformation mechanism were analyzed. Load-displacement curves of intra-ply shear tests were also analyzed. In addition, a MATLAB program was developed, using the Hough transform to analyze the shear angle in the real-time image taken during the displacement of the specimen at various positions. The image-analysis results were compared with the actual experimental results. These findings are important requirements when using 3-dimensional textile fabrics as the reinforcement in a composite formation.
3D spacer fabrics Image analysis Shear deformation Shear stress