关键词: 经编织物, 撕裂, 数值模型, 剪切, 拉剪耦合, 强度

Abstract: In order to explore the in-plane tearing behaviors and strength characters of fabric membranes under combined shear and tensile stresses，experimental and mesoscale numerical studies were conducted on a typical warp-knitted fabric membrane． Its specific tearing behaviors and strength characters under a series of stress ratios and stress levels，reinforced film types and coupled stresses were obtained，and the tearing mechanisms and failure behaviors of the material affected by shear-tension coupling stresses were analyzed． Ｒesults show that the fabric membranes could produce three kinds of appearance in terms of the orientation of the tear: line-shaped，crossshaped，and Z-shaped opening，which is depended on the crack orientation and stress states imposed on them，and the corresponding damage directions of yarns could belong to either warp or weft mode，instead of mixed modes． The stress states in warp and weft directions show the synergistic effect to offer the resistance to tear propagation， which affects the tearing strength obviously and leads to significant differences of tearing strength curves for different crack parameters in the stress space，resulting in the occurrence of stress strengthening at the stress ratio 1∶ 1． The stress state combined with reinforced film can obviously interfere with the tearing damage modes and crack position of membrane material，and the reinforcing effect varies depending on the stress ratios． In addition，during the tearing process，there is a coupling relationship between the tensile and shear stresses，and the tensile stress effect is the main one，while the shear stress has no obvious effect on the crack propagation and evolution． The research findings could provide references for the localized crack arresting of fabric membrane materials and safety assessment of membrane structures．

Key words: warp-knitted fabrics, tear, numerical model, shear, shear-tension coupling, strength