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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。
In order to study the shear mechanics properties of building fabric membrane, a new shear test method is proposed. A cruciform specimen of 16 cm in width and four arms in the center region was used. The warp and weft directions of the sample yarns were 45 ° to the loading direction. According to the relationship between membrane deformation and stress, the calculation methods of shear stress and shear strain are deduced. We define the loading spectrum that produces three cyclic shear stress fields in the central region of the specimen, and the cycle produces positive and negative alternating shear stress. The test uses the surface-polished polyvinylidene fluoride (PVDF) coating film to measure the stress and strain in the x and y directions. The shear stress-strain curve is calculated and the test results are analyzed. The results show that the new shear test method can reflect the shear properties of the fabric of the architectural fabric. Finally, the finite element method is used to simulate the stress and strain under the shear state of the material, which is close to the stress and strain values obtained from the experiment.