BS ISO 22889:2013
$198.66
Metallic materials. Method of test for the determination of resistance to stable crack extension using specimens of low constraint
| Published By | Publication Date | Number of Pages |
| BSI | 2013 | 60 |
This International Standard specifies methods for determining the resistance to stable crack extension in terms of crack opening displacement, δ5, and critical crack tip opening angle, ψc, for homogeneous metallic materials by the quasistatic loading of cracked specimens that exhibit low constraint to plastic deformation. Compact and middle-cracked tension specimens are notched, precracked by fatigue, and tested under slowly increasing displacement.
This International Standard describes methods covering tests on specimens not satisfying requirements for size-insensitive fracture properties; namely, compact specimens and middle-cracked tension specimens in relatively thin gauges.
Methods are given for determining the crack extension resistance curve (R-curve). Point values of fracture toughness for compact specimens are determined according to ISO 12135. Methods for determining point values of fracture toughness for the middle-cracked tension specimen are given in Annex D.
Crack extension resistance is determined using either the multiple-specimen or single-specimen method. The multiple-specimen method requires that each of several nominally identical specimens be loaded to a specified level of displacement. The extent of ductile crack extension is marked and the specimens are then broken open to allow measurement of crack extension. Single-specimen methods based on either unloading compliance or potential drop techniques can be used to measure crack extension, provided they meet specified accuracy requirements. Recommendations for single-specimen techniques are described in ISO 12135. Using either technique, the objective is to determine a sufficient number of data points to adequately describe the crack extension resistance behaviour of a material.
The measurement of δ5 is relatively simple and well established. The δ5 results are expressed in terms of a resistance curve, which has been shown to be unique within specified limits of crack extension. Beyond those limits, δ5 R-curves for compact specimens show a strong specimen dependency on specimen width, whereas the δ5 R-curves for middle-cracked tension specimens show a weak dependency.
CTOA is more difficult to determine experimentally. The critical CTOA is expressed in terms of a constant value achieved after a certain amount of crack extension. The CTOA concept has been shown to apply to very large amounts of crack extension and can be applied beyond the current limits of δ5 applications.
Both measures of crack extension resistance are suitable for structural assessment. The δ5 concept is well established and can be applied to structural integrity problems by means of simple crack driving force formulae from existing assessment procedures.
The CTOA concept is generally more accurate. Its structural application requires numerical methods, i.e. finite element analysis.
Investigations have shown a very close relation between the concept of constant CTOA and a unique R-curve for both compact and middle-cracked tension specimens up to maximum load. Further study is required to establish analytical or numerical relationships between the δ5 R-curve and the critical CTOA values.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 6 | Foreword |
| 7 | Introduction |
| 9 | Section sec_1 Section sec_2 1 Scope 2 Normative references |
| 10 | Section sec_3 Section sec_3.1 Section sec_3.2 Section sec_3.3 Section sec_3.4 Section sec_3.5 3 Terms and definitions |
| 11 | Section sec_4 Section sec_5 Section sec_5.1 4 Symbols 5 General requirements 5.1 Introduction |
| 12 | Table tab_1 Section sec_5.2 Section sec_5.2.1 Section sec_5.2.2 Section sec_5.2.2.1 5.2 Test specimens |
| 13 | Section sec_5.2.2.2 Section sec_5.2.2.3 Section sec_5.2.2.4 Section sec_5.2.2.4.1 Section sec_5.2.2.4.2 Section sec_5.2.2.4.3 |
| 14 | Section sec_5.2.2.4.4 Section sec_5.3 Section sec_5.3.1 Section sec_5.3.2 Section sec_5.4 Section sec_5.4.1 Section sec_5.4.2 5.3 Pre-test requirements 5.4 Test apparatus |
| 15 | Section sec_5.4.3 Section sec_5.4.4 Section sec_5.5 5.5 Test requirements |
| 16 | Section sec_5.5.1 Section sec_5.5.1.1 Section sec_5.5.1.2 Section sec_5.5.1.3 Section sec_5.5.2 Section sec_5.5.2.1 Section sec_5.5.2.2 Section sec_5.5.2.3 Section sec_5.5.3 Section sec_5.5.4 Section sec_5.5.5 |
| 17 | Section sec_5.5.6 Section sec_5.6 Section sec_5.6.1 Section sec_5.6.1.1 Section sec_5.6.1.2 Section sec_5.6.1.3 5.6 Post-test crack measurements |
| 18 | Section sec_5.6.2 Section sec_5.6.3 Section sec_5.6.3.1 Section sec_5.6.3.2 |
| 19 | Section sec_6 Section sec_6.1 Section sec_6.2 Section sec_6.2.1 Section sec_6.2.2 Section sec_6.2.3 Section sec_6.3 6 Determination of δ5 − Δa resistance curve and CTOA 6.1 General 6.2 Test procedure 6.3 R-curve plot |
| 20 | Section sec_6.3.1 Section sec_6.3.2 Section sec_6.4 6.4 Critical CTOA determination |
| 21 | Section sec_7 Section sec_7.1 Section sec_7.2 Section sec_7.2.1 7 Test report 7.1 General 7.2 Specimen, material and test environment |
| 22 | Section sec_7.2.2 Section sec_7.2.3 Section sec_7.2.4 Section sec_7.2.5 Section sec_7.3 Section sec_7.3.1 Section sec_7.3.2 Section sec_7.3.2.1 7.3 Test data qualification |
| 23 | Section sec_7.3.2.2 Section sec_7.3.3 Section sec_7.3.4 Section sec_7.3.5 |
| 24 | Section sec_7.4 Section sec_7.5 Figure fig_1 7.4 Qualification of the δ5 R-Curve 7.5 Qualification of ψc |
| 25 | Table tab_b Figure fig_2 |
| 26 | Table tab_c Figure fig_3 |
| 27 | Table tab_d Figure fig_4 |
| 28 | Table tab_e Figure fig_5 |
| 29 | Table tab_f Figure fig_6 |
| 30 | Table tab_g Figure fig_7 |
| 31 | Table tab_h Figure fig_8 |
| 32 | Table tab_i Figure fig_9 |
| 33 | Table tab_j Figure fig_10 |
| 34 | Table tab_k Figure fig_11 |
| 35 | Annex sec_A Table tab_A.1 Annex A (informative) Examples of test reports |
| 36 | Table tab_A.2 |
| 37 | Table tab_A.3 |
| 38 | Table tab_A.4 |
| 39 | Table tab_A.5 Table tab_A.6 |
| 40 | Annex sec_B Figure fig_B.1 Annex B (informative) Apparatus for measurement of crack opening displacement, δ5 |
| 41 | Figure fig_B.2 Table tab_l Figure fig_B.3 |
| 42 | Annex sec_C Annex sec_C.1 Annex sec_C.2 Annex sec_C.2.1 Annex sec_C.2.1.1 Annex sec_C.2.1.2 Annex C (informative) Determination of the crack tip opening angle, ψ |
| 43 | Annex sec_C.2.2 |
| 45 | Annex sec_C.3 Annex sec_C.3.1 |
| 46 | Annex sec_C.3.2 Annex sec_C.4 |
| 47 | Annex sec_C.5 Annex sec_C.5.1 Table tab_o Figure fig_C.1 |
| 48 | Table tab_p Figure fig_C.2 |
| 49 | Figure fig_C.3 |
| 50 | Table tab_q Figure fig_C.4 |
| 51 | Table tab_r Figure fig_C.5 |
| 52 | Annex sec_D Annex sec_D.1 Annex D (informative) Determination of point values of fracture toughness |
| 53 | Annex sec_D.2 Table tab_s Figure fig_D.1 |
| 54 | Table tab_t Figure fig_D.2 |
| 55 | Reference ref_1 Reference ref_2 Reference ref_3 Reference ref_4 Reference ref_5 Reference ref_6 Reference ref_7 Reference ref_8 Reference ref_9 Reference ref_10 Reference ref_11 Reference ref_12 Reference ref_13 Reference ref_14 Reference ref_15 Reference ref_16 Reference ref_17 Bibliography |
| 56 | Reference ref_18 Reference ref_19 Reference ref_20 |
