GB/T 9341-2000 in English

《GB/T 9341-2000塑料弯曲性能试验方法》由TC15（全国塑料标准化技术委员会）归口，TC15SC4（全国塑料标准化技术委员会通用方法和产品分会）执行，主管部门为中国石油和化学工业联合会。
本标准规定了在规定条件下测定塑料弯曲性能的方法，规定了标准试样，同时对适合使用的代替试样也提供了尺寸参数和试验速度范围。本方法用于在规定条件下研究试样的弯曲特性，测定弯曲强度、弯曲模量和弯曲应力-应变关系。本方法适用于两端自由支撑、中央加荷的试验（三点加荷试验）。本方法适用于下列材料：--热塑性模塑和挤塑材料，包括填充的和增强的未填充材料以及硬质热塑性板材；--热固性模塑材料，包括填充和增强材料，热固性板材，包括层压材料；--纤维增强热固性和热塑性复合材料，其含有单向或非单向的增强材料，如毡、纺织纤维、纺织粗纱、短切原丝、组合或混杂增强材料，无面粗纱和磨碎纤维等；由预浸渍材料制成的板材；--热致液晶聚合物。本方法一般不适用于硬质微孔材料和含有微孔材料的夹层结构材料。本方法采用的式样，可以是选定尺寸的模塑试样，也可以是用标准多用途式样中部机加工的试样，或用成品、半成品如模塑件、层压板、挤出或浇铸板材机加工的试样。本方法规定了最佳试样尺寸，用不同尺寸或不同条件制备的试样进行试验，其结果是不可比的。其他因素，如试验速度和试样的状态调节也会影响试验结果。因此，在要求数据比较时，必须仔细控制和纪录这些因素。只有具有线性应力-应变特性的材料，其弯曲性能才能作为工程设计的依据，而非线性材料的弯曲性能仅是公称值。对于脆性材料，及难于作拉伸试验的材料，最好采用弯曲试验。

Scope

1.1 This standard stipulates the method of measuring the bending properties of plastics under specified conditions, specifies the standard sample, and also provides the size parameters and test speed range for the suitable alternative sample. 1.2 This method is used to study the flexural properties of samples under specified conditions, and to determine the flexural strength, flexural modulus, and flexural stress-strain relationship. This method is applicable to tests with free support at both ends and central loading (three-point loading test). 1.3 This method is applicable to the following materials: - thermoplastic molding and extrusion materials, including filled and reinforced unfilled materials and rigid thermoplastic sheets; - thermosetting molding materials, including filled and reinforced materials, thermosetting sheet materials, including Laminates; - fibre-reinforced thermosetting and thermoplastic composites containing unidirectional or non-unidirectional reinforcements such as felts, textile fibres, textile rovings, chopped strands, combined or hybrid reinforcements, rovings and ground Shredded fibers, etc.; sheets made of pre-impregnated materials; - thermotropic liquid crystal polymers. This method is generally not suitable for hard microporous materials and sandwich structure materials containing microporous materials. Note 1: For some textile fiber reinforced plastics, it is better to use the four-point bending test. 1.4 The test specimens used in this method may be molded specimens of selected dimensions, or specimens machined from the middle of standard multipurpose specimens, or specimens made of finished or semi-finished products such as molded parts, laminates, extruded or machined specimens from cast plate. 1.5 This method specifies the optimum sample size, and the test results are incomparable with samples of different sizes or prepared under different conditions. Other factors, such as test speed and conditioning of the specimen can also affect test results. Therefore, these factors must be carefully controlled and documented when data comparisons are required. 1.6 Only materials with linear stress-strain characteristics can be used as the basis for engineering design, while the bending properties of nonlinear materials are only nominal values. For brittle materials, that is, materials that are difficult to perform tensile tests, the bending test is best used.