1.1本试验方法²涵盖了从接近阈值到 K 最大值 受控不稳定性。结果表示为裂纹尖端应力强度因子范围（Δ K )，由线弹性理论定义。 1.2提供了几种不同的试验程序，最佳试验程序主要取决于待测疲劳裂纹扩展速率的大小。 1.3可以通过本试验方法进行试验的材料不受厚度或强度的限制，只要试样具有足够的厚度以防止屈曲，并且具有足够的平面尺寸以在试验期间保持主要弹性。 1.4提供了一系列具有比例平面尺寸的试样尺寸，但尺寸是可变的，可根据屈服强度和施加的力进行调整。 试样厚度可以独立于平面尺寸而变化。 1.5各种试样和试验配置的详细信息见附录A1和附录A3。可使用本方法中包含的样本配置以外的其他样本配置，前提是可以进行完善的应力强度因子校准，并且样本具有足够的平面尺寸，以在测试期间保持主要弹性。 1.6残余应力/裂纹闭合可能会显著影响疲劳裂纹扩展速率数据，尤其是在低应力强度因子和低应力比下，尽管这些变量未纳入Δ的计算中 K . 1.7以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 1.8本试验方法分为两个主要部分。第一部分给出了有关疲劳裂纹扩展速率试验的建议和要求的一般信息。第二部分由附录组成，这些附录描述了各种样本配置的特殊要求、水环境中测试的特殊要求以及非目视裂纹尺寸测定程序。此外，附录涵盖了计算da/dN、确定疲劳裂纹张开力的技术，以及测量小疲劳裂纹扩展的指南。所有样本类型的通用信息和要求如下: 部分 参考文件 2. 术语 3. 使用摘要 4. 意义和用途 5. 仪器 6. 试样结构、尺寸和制备 7. 程序 8. 结果的计算和解释 9 汇报 10 精度和偏差 11 水环境试验的特殊要求 附件A4 使用合规性确定裂纹尺寸的指南 附件A5 裂纹尺寸的电位差测定指南 附录A6 推荐的数据简化技术 附录X1 根据柔度确定疲劳裂纹张开力的推荐规程 附录X2 测量小疲劳裂纹扩展速率的指南 附录X3 1.9各种试样配置的特殊要求按以下顺序出现: 紧凑拉伸试样 附件A1 中间拉伸试样 附件A2 古怪的- 加载单边裂纹拉伸试样 附件A3 1.10 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和健康实践，并确定监管限制的适用性。

1.1 This test method² covers the determination of fatigue crack growth rates from near-threshold to K max controlled instability. Results are expressed in terms of the crack-tip stress-intensity factor range (Δ K ), defined by the theory of linear elasticity. 1.2 Several different test procedures are provided, the optimum test procedure being primarily dependent on the magnitude of the fatigue crack growth rate to be measured. 1.3 Materials that can be tested by this test method are not limited by thickness or by strength so long as specimens are of sufficient thickness to preclude buckling and of sufficient planar size to remain predominantly elastic during testing. 1.4 A range of specimen sizes with proportional planar dimensions is provided, but size is variable to be adjusted for yield strength and applied force. Specimen thickness may be varied independent of planar size. 1.5 The details of the various specimens and test configurations are shown in Annex A1-Annex A3. Specimen configurations other than those contained in this method may be used provided that well-established stress-intensity factor calibrations are available and that specimens are of sufficient planar size to remain predominantly elastic during testing. 1.6 Residual stress/crack closure may significantly influence the fatigue crack growth rate data, particularly at low stress-intensity factors and low stress ratios, although such variables are not incorporated into the computation of Δ K . 1.7 Values stated in SI units are to be regarded as the standard. Values given in parentheses are for information only. 1.8 This test method is divided into two main parts. The first part gives general information concerning the recommendations and requirements for fatigue crack growth rate testing. The second part is composed of annexes that describe the special requirements for various specimen configurations, special requirements for testing in aqueous environments, and procedures for non-visual crack size determination. In addition, there are appendices that cover techniques for calculating da/dN, determining fatigue crack opening force, and guidelines for measuring the growth of small fatigue cracks. General information and requirements common to all specimen types are listed as follows: Section Referenced Documents 2 Terminology 3 Summary of Use 4 Significance and Use 5 Apparatus 6 Specimen Configuration, Size, and Preparation 7 Procedure 8 Calculations and Interpretation of Results 9 Report 10 Precision and Bias 11 Special Requirements for Testing in Aqueous Environments Annex A4 Guidelines for Use of Compliance to Determine Crack Size Annex A5 Guidelines for Electric Potential Difference Determination of Crack Size Annex A6 Recommended Data Reduction Techniques Appendix X1 Recommended Practice for Determination of Fatigue Crack Opening Force From Compliance Appendix X2 Guidelines for Measuring the Growth Rates Of Small Fatigue Cracks Appendix X3 1.9 Special requirements for the various specimen configurations appear in the following order: The Compact Tension Specimen Annex A1 The Middle Tension Specimen Annex A2 The Eccentrically-Loaded Single Edge Crack Tension Specimen Annex A3 1.10 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 and health practices and determine the applicability of regulatory limitations prior to use.