聚酯纤维机织物-聚氯乙烯-聚偏氟乙烯膜材双轴剪切力学性能试验

为研究聚酯纤维机织物-聚氯乙烯-聚偏氟乙烯(P-PVC-PVDF)膜材的双轴剪切力学性能,提出了工程剪应变计算方法、改进的剪应力计算方法和应力加载方法。基于自主研制的双轴拉伸试验机,对P-PVC-PVDF膜材进行了双轴剪切力学性能试验,得到了膜材剪应力-剪应变曲线、剪切模量和滞回环面积。分析结果表明,剪应力由正变为负后,各力学参数有所差异,但均在加载一次后趋于稳定。当剪应力的上下限设定为±2kN/m时,稳定后的剪切模量范围为11~13kN/m。通过对比证明,主轴与加载方向的夹角变化对计算结果影响不大。研究成果对膜结构设计与分析具有参考价值。

Test on biaxial shear mechanical performance of polyester fabric-polyvinyl chloride-polyvinylidene fluoride membrane

In order to study the biaxial shear mechanical performance of the polyester fabric-polyvinyl chloride-polyvinylidene fluoride (P-PVC-PVDF) membrane, the calculation formula for engineering shear strain, the modified formula for shear stress, and the method for stress loading were given. The biaxial shear test of P-PVC-PVDF membrane was then carried out using a self-developed biaxial tensile tester. The shear stress-strain curves, shear modulus and hysteresis loop area were obtained. The analysis results show that the mechanical parameters are different when the direction of shear stress is changed. However, all the mechanical parameters turn stable after the first loading cycle. The range of stable shear modulus is 11-13 kN/m when the up and lower limit of shear stress is set to be ±2 kN/m. The change of the angle between the principle axial and the direction of loading has little influence on the calculation result. These results can be useful for the analysis and design of membrane structures.