1.1 本试验方法包括测定 J -积分与裂纹扩展阻力( J-R公司 )聚合物材料的曲线。 1.2 本试验方法旨在表征弯曲型试样的缓慢、稳定的裂纹扩展阻力，使其在本试验方法规定的限值内对几何形状不敏感。 1.3 推荐的试样为三点弯曲试样( 东南方 ( B ))和销加载紧凑张力( C ( T ))样本。对于所有尺寸，两个试样的平面内尺寸均为恒定比例。除本试验方法中建议的试样配置外，可能需要不同的程序和有效性要求。 1.4 本试验方法描述了一种多试样方法，该方法要求对断裂表面的裂纹扩展进行光学测量。不建议将其用于裂纹前缘无法与裂纹尖端之前的附加变形过程区分开来的材料。 1.5 以国际单位制表示的数值应视为标准。 1.6 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: 没有已知的ISO等效于本标准。 1.7 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 A. J-R公司 根据本试验方法绘制的曲线表征了各种韧性聚合物和聚合物共混物的裂纹扩展阻力 ( 1- 5. ) 4. 在测试方法中，无法获得足够的尺寸和厚度，以通过线弹性断裂力学进行有效表征 D5045 . 5.2 这个 J-R公司 在本试验方法规定的限制范围内，该曲线表征了聚合物材料在从先前存在的尖锐缺陷开始后减缓稳定裂纹扩展的阻力。 5.3 A. J-R公司 曲线可以用作共混物或合金设计、材料选择、材料加工和质量保证的材料韧性指标 ( 6. ) . 5.4 这个 J-R公司 弯曲试样的曲线表示以下参数的下限估计值: J 承载力是裂纹扩展的函数，与拉伸载荷下从试样结构获得的承载力相比，已观察到该承载力是保守的。 5.5 这个 J-R公司 随着厚度的增加，具有恒定微观结构的给定材料的曲线往往表现出较低的斜率（更平坦）。因此，建议使用具有代表性微观结构的最大可能试样。 5.6 这个 J-R公司 曲线可用于评估存在韧性撕裂时结构中裂纹的稳定性，同时了解实验室测试和现场条件之间可能存在的差异。 5.7 A. J-R公司 曲线可能取决于与材料各向异性相关的裂纹方向和扩展，材料各向异性可能由试样制造方法引起。 5.8 由于裂纹扩展阻力可能与速率相关， J-R公司 可以在本试验方法规定以外的位移速率下测定曲线 ( 7. ) .

1.1 This test method covers the determination of the J -integral versus crack growth resistance ( J-R ) curves for polymeric materials. 1.2 This test method is intended to characterize the slow, stable crack growth resistance of bend-type specimens in such a manner that it is geometry insensitive within limits set forth in this test method. 1.3 The recommended specimens are the three-point bend ( SE ( B )) and pin-loaded compact tension ( C ( T )) specimens. Both specimens have in-plane dimensions of constant proportionality for all sizes. Specimen configurations other than those recommended in this test method may require different procedures and validity requirements. 1.4 This test method describes a multiple specimen method that requires optical measurement of crack extension from fracture surfaces. It is not recommended for use with materials in which the crack front cannot be distinguished from additional deformation processes in advance of the crack tip. 1.5 The values stated in SI units are to be regarded as the standard. 1.6 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: There is no known ISO equivalent to this standard. 1.7 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 A J-R curve produced in accordance with this test method characterizes the crack growth resistances of a wide range of tough polymers and polymer blends ( 1- 5 ) 4 that cannot be obtained in sufficient size and thickness for valid characterization by linear elastic fracture mechanics in Test Methods D5045 . 5.2 The J-R curve characterizes, within the limits set forth in this test method, the resistance of a polymeric material to slow stable crack growth after initiation from a preexisting sharp flaw. 5.3 A J-R curve can be used as an index of material toughness for blend or alloy design, material selection, materials processing, and quality assurance ( 6 ) . 5.4 The J-R curves from bend specimens represent lower bound estimates of J capacity as a function of crack extension, and have been observed to be conservative relative to those obtained from specimen configurations under tensile loading. 5.5 The J-R curves for a given material of constant microstructure tend to exhibit lower slope (flatter) with increasing thickness. Thus, it is recommended that the largest possible specimen with representative microstructure be used. 5.6 The J-R curve can be used to assess the stability of cracks in structures in the presence of ductile tearing, with awareness of the differences that may exist between laboratory test and field conditions. 5.7 A J-R curve may depend on the orientation and propagation of the crack in relation to the anisotropy of the material which may be induced by specimen fabrication methods. 5.8 Because of the possibility of rate dependence of crack growth resistance, J-R curves can be determined at displacement rates other than that specified in this test method ( 7 ) .