1.1 这些试验方法包括测定玻璃和玻璃陶瓷的弯曲强度（弯曲断裂模量）。 1.2 这些测试方法适用于退火和预应力玻璃以及各种形式的玻璃陶瓷。描述了替代测试方法；所用的试验方法应根据试验目的和代表材料的试样的几何特征来确定。 1.2.1 试验方法A是平板玻璃弯曲强度的试验。 1.2.2 试验方法B是玻璃和玻璃陶瓷的弯曲强度的比较试验。 1.3 测试方法按以下顺序出现: 章节 试验方法A 7. 到 10 试验方法B 11 到 16 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ===意义和用途====== 4.1 就本试验而言，玻璃和玻璃陶瓷被认为是脆性的（完全弹性的），并且具有在主拉伸应力作用下试样表面通常发生断裂的特性。弯曲强度被认为是抗拉强度的有效衡量标准，但需考虑以下因素。 4.2 一组试样的弯曲强度受到与试验程序相关的变量的影响。这些因素在测试程序中有规定或要求在报告中说明。这些因素包括但不限于应力速率、试验环境和试样承受应力的面积。 4.2.1 此外，对一组试样的抗弯强度值影响最大的变量是表面状况和表面附近的玻璃质量，涉及应力集中不连续或缺陷的数量和严重程度，以及试样中存在的预应力程度。这些中的每一个都可以表示正在确定的强度特性的固有部分，或者可以是测量中的随机干扰因素。 4.2.2 试验方法A旨在将试样表面状况作为测量强度的一个因素。因此，使表面的固定且显著的区域经受最大拉伸应力是合乎需要的。由于玻璃表面缺陷的数量和严重程度主要由制造和处理过程决定，因此该测试方法仅限于可以获得合适尺寸试样的产品，而测量强度对试样制备技术的依赖性最小。 因此，该试验方法被指定为平板玻璃的弯曲强度试验。 4.2.3 试验方法B描述了适用于矩形或椭圆形横截面试样的一般试验程序。该试验方法基于这样一种假设，即对试样组强度的比较测量对许多目的具有重要意义，例如:确定环境或应力持续时间的影响、各种预应力技术的有效性，以及不同成分或热处理的玻璃陶瓷的强度特征。在该试验方法中，试样的表面不被认为是产品或材料的特征，而是被认为是由制备试样所用的程序确定的。尽管规定的程序允许试样尺寸和试验几何结构的大范围变化，但为了获得可比较的强度值，有必要使用相同的试验条件和等效的试样制备程序。 建议将试样的受控磨损作为此类比较试验的最终正火程序。 4.2.4 按照试验方法B的建议确定的比较磨损强度不应被视为试验材料的最小值特征，也不应与通过对具有相同缺陷的试样进行试验获得的最大强度值直接相关。当应用于不同的材料时，操作定义的磨损程序无疑会产生不同严重程度的缺陷，测量的比较强度描述了承受特定磨损程序影响的外部诱导应力的相对能力。 4.2.5 测试环境（环境空气、惰性气体、真空等）包括水分含量（例如，相对湿度）可能会对弯曲强度产生影响。评估玻璃最大强度潜力的测试可以在惰性环境中进行和/或以足够快的测试速率进行，以最大限度地减少任何环境影响。 相反，可以在代表使用条件的环境、测试模式和测试速率下进行测试，以评估使用条件下的弯曲性能。

1.1 These test methods cover the determination of the flexural strength (the modulus of rupture in bending) of glass and glass-ceramics. 1.2 These test methods are applicable to annealed and prestressed glasses and glass-ceramics available in varied forms. Alternative test methods are described; the test method used shall be determined by the purpose of the test and geometric characteristics of specimens representative of the material. 1.2.1 Test Method A is a test for flexural strength of flat glass. 1.2.2 Test Method B is a comparative test for flexural strength of glass and glass-ceramics. 1.3 The test methods appear in the following order: Sections Test Method A 7 to 10 Test Method B 11 to 16 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 For the purpose of this test, glasses and glass-ceramics are considered brittle (perfectly elastic) and to have the property that fracture normally occurs at the surface of the test specimen from the principal tensile stress. The flexural strength is considered a valid measure of the tensile strength subject to the considerations that follow. 4.2 The flexural strength for a group of test specimens is influenced by variables associated with the test procedure. Such factors are specified in the test procedure or required to be stated in the report. These include but are not limited to the rate of stressing, the test environment, and the area of the specimen subjected to stress. 4.2.1 In addition, the variables having the greatest effect on the flexural strength value for a group of test specimens are the condition of the surfaces and glass quality near the surfaces in regard to the number and severity of stress-concentrating discontinuities or flaws, and the degree of prestress existing in the specimens. Each of these can represent an inherent part of the strength characteristic being determined or can be a random interfering factor in the measurement. 4.2.2 Test Method A is designed to include the condition of the surface of the specimen as a factor in the measured strength. Therefore, subjecting a fixed and significant area of the surface to the maximum tensile stress is desirable. Since the number and severity of surface flaws in glass are primarily determined by manufacturing and handling processes, this test method is limited to products from which specimens of suitable size can be obtained with minimal dependence of measured strength upon specimen preparation techniques. This test method is therefore designated as a test for flexural strength of flat glass. 4.2.3 Test Method B describes a general procedure for test, applicable to specimens of rectangular or elliptical cross section. This test method is based on the assumption that a comparative measurement of strength on groups of specimens is of significance for many purposes such as: determining the effect of environment or stress duration, the effectiveness of varied prestressing techniques, and strengths characteristic of glass-ceramics of differing composition or heat treatment. In this test method, the surfaces of the specimens are not assumed to be characteristic of a product or material, but are considered to be determined by the procedures used to prepare the specimens. Though the stated procedure permits a wide variation in both specimen size and test geometry, use of identical test conditions and equivalent procedures for specimen preparation is necessary to obtain comparable strength values. The use of a controlled abrasion of the specimen as a final normalizing procedure is recommended for such comparative tests. 4.2.4 A comparative abraded strength, determined as suggested in Test Method B, is not to be considered as a minimum value characteristic of the material tested nor as directly related to a maximum attainable strength value through test of specimens with identical flaws. The operationally defined abrasion procedure undoubtedly produces flaws of differing severity when applied to varied materials, and the measured comparative strengths describe the relative ability to withstand externally induced stress as affected by the specific abrasion procedure. 4.2.5 Test environment (ambient air, inert gas, vacuum, etc.) including moisture content (for example, relative humidity) may have an influence on the flexural strength. Testing to evaluate the maximum strength potential of a glass can be conducted in inert environments and/or at sufficiently rapid testing rates to minimize any environmental effects. Conversely, testing can be conducted in environments, test modes, and test rates representative of service conditions to evaluate flexural performance under use conditions.