Modified stress field model for critical tearing strength of architectural coated fabrics

This report presents a new critical tearing strength prediction model, the modified stress field model. Firstly, the critical tearing strength of six coated fabrics is obtained using the single-edge notched tests. The results show that the warp and weft strength utilization of different coated fabrics is similar. Based on the test data, the prediction effects, parameter meanings, and basic properties of three models, namely Thiele’s empirical formula, the stress field model, and the modified stress field model, are discussed and compared. Then, the predicted results and properties of the three models in different crack ranges, specifically the small crack range, are compared, and their application scopes are verified. The two commonly used models lack the improved prediction effects in the small crack range that is provided by the modified stress field model. Finally, to reduce the workload while maintaining a certain accuracy, a crack combination of 3 mm + 15 mm is recommended, which is further confirmed using the root-mean-square error index. The prediction results of Thiele’s empirical formula and the modified stress field model under this crack combination are compared. The new model can still maintain good prediction effects even when extrapolating for small cracks using limited test data. Because of its precision and convenience, the proposed model may relatively facilitate the application of single-edge notched or uniaxial central tearing tests.