Anisotropy in geometrical and tensile properties of plain weave fabric: verifying a semi-empirical model

Geometrical and mechanical behaviors of fabric are extremely anisotropic. Exploit of fabric in multiplicity applications is dependent on its behavior in differ directions. Thus, attempts had been made to study the behavior of fabric in off and on axis systematically. For this purpose, authority of a semi-empirical model, based on earlier work, was experimentally investigated. The model consists of a numerical way to estimate yarn path under axial and normal tension simultaneously. A test method to evaluate flattening of yarn was presented in this study. Moreover, to reduce stress concentration at the sample’s corners a modified griper was applied. On the basis of initial data of fabric and flattening behavior of constitutive yarns, the fabric geometry and tensile force–strain (TF–S) curve of a strip fabric in arbitrary direction are capable to estimate using stated model. The variations in density of warp and weft yarns, shear angle, and TF–S curve of a fabric in different directions were measured and are compared with theoretical values. It was found that the stated model is applicable to predict fabric geometry and tensile behavior of a plain weave fabric under stress in arbitrary direction. Experimental results indicated that the strength of fabric at 45 degree was 22.59% higher than the strength of fabric in average of principal directions. On the basis of semi-empirical model, it is anticipated that the maximum strength of presented fabric would be occurred at 60 degree with 27.99% higher than the strength of fabric in average of principal directions.