PTFE膜材料的偏轴拉伸性能及破坏机理

为深入把握PTFE膜材料的率相关力学性能及破坏机理,对3种常见的PTFE膜材料进行了偏轴拉伸试验,主要考虑了0°、5°、15°、25°、35°、45°、55°、65°、75°、85°、90°等11个偏轴角度和10、25、50、100、200、500 mm/min等6种拉伸速率,分析了主要力学参数的变化规律,研究了不同拉伸速率下的膜材破坏模式及破坏机理.结果表明:不同拉伸速率下膜材主要力学参数的变化规律比较一致,表现出明显的各向异性;材料的抗拉强度与破坏模式密切相关,随着拉伸速率的增加,抗拉强度逐渐升高,且与拉伸速率的对数呈近似线性关系,这主要与材料应变能及编织结构有关;材料的破坏模式和断裂延伸率受拉伸速率的变化影响不明显.

Off-axial tensile behaviors and failure mechanisms of PTFE coated fabrics

To understand the rate-dependent mechanical properties and failure mechanism, a series of uniaxial off-axial tensile tests were carried out to study the mechanical properties of three common PTFE (Poly tetra fluoro ethylene) coated fabrics under different tensile rates. The following parameters were considered in the tests including eleven in-plane directions (0°, 5°, 15°, 25°, 35°, 45°, 55°, 65°, 75°, 85°and 90°) and six tensile rates (10 mm/min, 25 mm/min, 50 mm/min, 100 mm/min, 200 mm/min, and 500 mm/min). The variations of main mechanical parameters of PTFE coated fabrics were analyzed and the corresponding tensile failure modes and mechanisms were studied. The results show that the variations of main mechanical parameters are consistent under different tensile rates and it shows significant anisotropic characteristic. The tensile strength is strongly related with the failure modes. With tensile rate increasing, the tensile strength increases slightly while the strain at break decreases. The tensile strength shows good linear relationship with the tensile rate''s logarithm, which is mainly related with the strain energy and the woven structure. The change of tensile rate has no significant effects on the material failure modes and the strain at break.