Experimental analysis of the forming behavior of uni- and bidirectional non-crimp fabrics for different geometries

For efficient large-series production and improved process design, a profound understanding of a textile’s forming behavior is crucial to ensure adequate drapability and defect-free components. Woven fabrics have often been the focus of research due to their easier formability, while non-crimp fabrics (NCFs) have been investigated much less despite their higher lightweight potential, resulting in a limited experimental basis for the validation of numerical models. Therefore, forming experiments of a unidirectional and a bidirectional NCF are conducted for different configurations and punch shapes, including hemisphere, tetrahedron, and square box. The macroscopic strains are captured throughout the entire process using digital image correlation (DIC) and comprehensively analyzed in combination with the outer contour and resulting defects. Fundamental differences in the deformation behavior of both textiles are identified. For the balanced Biax-NCF, the tricot stitching couples the deformation of both fiber layers and the fabric mainly deforms under symmetrical shear with limited yarn slippage or defects. For the highly unbalanced UD-NCF, the lack of a second fiber direction results in an asymmetrical deformation behavior. ... mehrThe UD-NCF deforms due to shear parallel to the fiber yarns superimposed with transverse tensile and compressive strains in different deformation modes. The data generated in this study is freely available at https://doi.org/10.5281/zenodo.12516897.