建筑织物膜材双轴剪切试验与分析

为了研究建筑织物膜材的剪切力学性能,提出一种新的剪切测试方法。采用中心区域宽度和四臂长度均为16cm的十字形试件,试件纱线的经纬向与加载方向呈45°角。根据膜材变形和应力关系,推导了剪应力和剪应变的计算方法。定义了使试件中心区域产生三个循环剪应力场的加载谱,循环产生正负交替的剪切应力。试验采用表面抛光的(Polyvinylidene Fluoride,聚偏氟乙烯)涂层膜材,测量x、y两个方向的应力和应变,通过计算得到剪切应力应变曲线,并对试验结果进行分析。结果表明,新的剪切测试方法能够反映建筑织物膜材剪切力学性能。最后通过有限元方法模拟材料受剪状态下的应力和应变,与试验得到的应力值和应变值相近。

Biaxial Shear Experiment and Analysis for Architectural Fabric Membrane Material

In order to investigate the shear characteristics of architectural fabric membrane material, a new shear measurement method is proposed in this paper. Cruciform specimens, the width of central region and the length of four arms of which are all 16 cm, and its warp and weft directions are 45 degrees with respect to loading direction respectively. According to the relationship between membrane material deformation and stress, the calculation methods of shear stress and shear strain were defined. The loading history was defined to generate three cyclic shear stress field with positive and negative cycle in central region of specimen. PVDF(Polyvinylidene Fluoride) with surface finish was adopted as coating fabric membrane material in experiment, and shear stress and shear strain were measured in x and y direction, respectively. Shear stress-strain curve was obtained by calculation and the measured results were analyzed. Results show that the new shear measurement method can reflect the shear characteristics of architectural fabric membrane material. Finally, FE simulation was carried out for shear stress and strain, its results were compared with experimental ones.