纤维增强塑料复合材料 用板捻法测定内剪模量

[中文适用范围]： 本国际标准规定了使用标准板试样测定纤维增强塑料复合材料面内剪切模量（G12）的方法。 当应用于各向同性材料时，测量的剪切模量与方向无关。 2 本方法用于测定试样的剪切模量，但不测定剪切强度。 它适用于在一个对角线上的两个点支撑的板，并通过连接到横梁的两个加载点的同时移动在另一对角线上加载。 3 该方法适用于热固性和热塑性基体的纤维增强塑料复合材料。 由于在弯曲条件下施加剪切变形，对于具有不同纤维形式和/或不同取向的层压材料，材料层必须在截面上良好分布，使得其在厚度方向上近似“均匀”。 主材料轴（如果存在）必须垂直于板边缘（参见 3.8）。 注：该方法可应用于非增强聚合物和其他材料（例如金属、陶瓷和金属或陶瓷基复合材料）。 对于使用单向层片制造的材料，使用多向样本（即0°/90°/±45°）获得的剪切模量与单向或交叉层片（0°/90°）材料获得的剪切模量不同。 4 该方法使用样本进行，样本可以模制为选定的尺寸，由测试板加工而成，或者由产品的平坦区域加工而成。 5 该方法规定了样品的首选尺寸。 对其他尺寸的样品或在不同条件下制备的样品进行的测试可能会产生不可比较的结果。 其他因素，例如测试速度和样品的条件，也会影响结果。 因此，当需要比较数据时，必须仔细控制和记录这些因素。 注：在较高应变水平下，剪切应力应变响应是非常非线性的。 该测试方法确定低应变区域内的模量，不适用于较高应变。 [外文原描述]： 1.1 This International Standard specifies a method for determining the in-plane shear modulus ( G 12) of fibrereinforced plastic composites using a standard plate specimen. When applied to isotropic materials, the shear modulus measured is independent of direction. 1.2 The method is used to determine the shear modulus of the test specimens but not to determine the shear strength. It applies to a plate supported on two points on one diagonal and loaded on the other diagonal by the simultaneous movement of two loading points attached to a cross-beam. 1.3 The method is suitable for use with fibre-reinforced plastic composites with both thermoset and thermoplastic matrices. Due to the shear deformation being applied under flexural conditions, for laminated materials with different fibre formats and/or different orientations, the layers of material must be well distributed across the section so that it is approximately "homogeneous" in the through-thickness direction. The principal material axes, if present, must be orientated normal to the plate edges (see 3.8). NOTE This method can be applied to unreinforced polymers and other materials (e.g. metals, ceramics and metal- or ceramic-matrix composites). For material fabricated using unidirectional plies, the shear modulus obtained using a multidirectional specimen (i.e. 0°/90°/_ 45°) is not the same as that obtained for unidirectional or cross-ply (0°/90°) material. 1.4 The method is performed using specimens which may be moulded to the chosen dimensions, machined from test plates or machined from flat areas of products. 1.5 The method specifies preferred dimensions for the specimen. Tests which are carried out on specimens of other dimensions, or on specimens which are prepared under different conditions, may produce results which are not comparable. Other factors, such as the speed of testing and the conditioning of the specimens, can influence the results. Consequently, when comparative data are required, these factors must be carefully controlled and recorded. NOTE The stress-strain response in shear is very non-linear at higher strain levels. This test method determines the modulus within a low strain region and is not applicable to higher strains.