1.1 本试验方法包括测定拉挤开放式和封闭式纤维增强聚合物（FRP）复合材料的弯曲模量，该复合材料具有双对称截面（长轴和短轴均具有几何对称的截面），其几何质心承受弯曲和剪切。该测试方法利用应用于简支梁的三点加载系统。 1.2 以国际单位制表示的数值应视为标准。括号中提供的值仅供参考。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。 本标准的用户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。 注1: 目前尚无与本标准等效的ISO。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 通过本试验方法测定弯曲模量对于质量控制和规范目的特别有用。 5.2 弯曲模量的实验值将随试样深度、跨度、加载速率、环境试验温度和其他大气条件而变化。 5.3 在继续使用本试验方法之前，应参考被测材料的规范，包括试样的组成材料。材料规范中涵盖的任何试样制备、环境或负载条件、尺寸或测试参数，或两者，应优先于本试验方法中提及的内容。 如果没有材料规范，则适用这些默认条件。分类中的表1 D4000 列出了当前存在的ASTM材料标准。

1.1 This test method covers the determination of Flexural Modulus of pultruded open and closed fiber reinforced polymer (FRP) composites of doubly symmetrical cross sections (sections having geometric symmetry about both the major and minor axes) about their geometric centroid subjected to flexure and shear. This test method utilizes a three-point loading system applied to a simply supported beam. 1.2 The values stated in SI units are to be regarded as the standard. The values provided in parentheses are for information only. 1.3 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. Note 1: The is no known ISO equivalent to this standard. 1.4 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 ====== 5.1 Determination of flexural modulus by this test method is especially useful for quality control and specification purposes. 5.2 Experimental values for flexural modulus will vary with specimen depth, span length, loading rate, ambient test temperature, and other atmospheric conditions. 5.3 Before proceeding with this test method, reference should be made to the specification of the material being tested, including constituent materials of the specimen. Any test specimen preparation, environmental or loading conditioning, dimensions, or testing parameters covered in the material specification, or both, shall take precedence over those mentioned in this test method. If there are no material specifications, then these default conditions apply. Table 1 in Classification D4000 lists the ASTM materials standards that currently exist.