ASTM E2472-12e1
測定在低約束條件下抗穩定裂紋擴展性的標準試驗方法

Standard Test Method for Determination of Resistance to Stable Crack Extension under Low-Constraint Conditions

被代替

標準號

ASTM E2472-12e1

發布

2012年

發布單位

美國材料與試驗協會

替代標準

ASTM E2472-12(2018)

當前最新

ASTM E2472-12(2018)e3

 

 

引用標準

ASTM E1290 ASTM E1820 ASTM E1823 ASTM E2309 ASTM E399 ASTM E4 ASTM E561 ASTM E647 ASTM E8/E8M ISO 12135

適用范圍

5.1 This test method characterizes a metallic material’s resistance to stable crack extension in terms of crack-tip-opening angle (CTOA), ψ and/or crack-opening displacement (COD), δ₅ under the laboratory or application environment of interest. This method applies specifically to fatigue pre-cracked specimens that exhibit low constraint and that are tested under slowly increasing displacement.

5.2 When conducting fracture tests, the user must consider the influence that the loading rate and laboratory environment may have on the fracture parameters. The user should perform a literature review to determine if loading rate effects have been observed previously in the material at the specific temperature and environment being tested. The user should document specific information pertaining to their material, loading rates, temperature, and environment (relative humidity) for each test.

5.3 The results of this characterization include the determination of a critical, lower-limiting value, of CTOA (ψ _c) or a resistance curve of δ₅, a measure of crack-opening displacement against crack extension, or both.

5.4 The test specimens are the compact, C(T), and middle-crack-tension, M(T), specimens.

5.5 Materials that can be evaluated by this standard are not limited by strength, thickness, or toughness, if the crack-size-to-thickness (a/B) ratio or ligament-to-thickness (b/B) ratio are equal to or greater than 4, which ensures relatively low and similar global crack-front constraint for both the C(T) and M(T) specimens (2, 3).

5.6 The values of CTOA and COD (δ₅) determined by this test method may serve the following purposes:

5.6.1 In research and development, CTOA (ψ_c) or COD (δ₅), or both, testing can show the effects of certain parameters on the resistance to stable crack extension of metallic materials significant to service performance. These parameters include, but are not limited to, material thickness, material composition, thermo-mechanical processing, welding, and thermal stress relief.

5.6.2 For specifications of acceptance and manufacturing quality control of base materials.

5.6.3 For inspection and flaw assessment criteria, when used in conjunction with fracture mechanics analyses. Awareness of differences that may exist between laboratory test and field conditions is required to make proper flaw assessment.

5.6.4 The critical CTOA (ψ

ASTM E2472-12e1相似標準