Shear deformation characterization and normalized method of tricot-stitched unidirectional non-crimp fabric

Currently, the shear deformation of unidirectional non-crimp fabric (UD-NCF) is investigated sparsely, especially for the normalized method. Thus, this work systematically explored the shear behavior of UD-NCF by the off-axis extension test under different off-axis angles. The evolution rule of macro shear mechanical behavior was discussed and the effect mechanism of off-axis angle on the extension force degree and its standard deviation was revealed. Then, by analyzing the fabric morphology and deformation contour, the supporting yarn with the relatively large linear density will affect the shear deformation of UD-NCF and induce the meso buckling defect of main yarn. Most importantly, the developed normalized shear force methods suitable for the UD-NCF were derived, and the difference of normalized shear force among developed and reported methods was discussed and identified.