ASTM E399-22
(Test Method)Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness of Metallic Materials
Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness of Metallic Materials
SIGNIFICANCE AND USE
5.1 The property KIc determined by this test method characterizes the resistance of a material to fracture in a neutral environment in the presence of a sharp crack under essentially linear-elastic stress and severe tensile constraint, such that (1) the state of stress near the crack front approaches tritensile plane strain, and (2) the crack-tip plastic zone is small compared to the crack size, specimen thickness, and ligament ahead of the crack.
5.1.1 Variation in the value of KIc can be expected within the allowable range of specimen proportions, a/W and W/B. KIc may also be expected to rise with increasing ligament size. Notwithstanding these variations, however, KIc is believed to represent a lower limiting value of fracture toughness (for 2 % apparent crack extension) in the environment and at the speed and temperature of the test.
5.1.2 Lower values of KIc can be obtained for materials that fail by cleavage fracture; for example, ferritic steels in the ductile-to-brittle transition region or below, where the crack front length affects the measurement in a stochastic manner independent of crack front constraint. The present test method does not apply to such materials and the user is referred to Test Method E1921 and E1820. Likewise this test method does not apply to high toughness or high tearing-resistance materials whose failure is accompanied by appreciable amounts of plasticity. Guidance on testing elastic-plastic materials is given in Test Method E1820.
5.1.3 The value of KIc obtained by this test method may be used to estimate the relation between failure stress and crack size for a material in service wherein the conditions of high constraint described above would be expected. Background information concerning the basis for development of this test method in terms of linear elastic fracture mechanics may be found in Refs (1) and (2).
5.1.4 Cyclic forces can cause crack extension at KI values less than KIc. Crack extension under cyclic or s...
SCOPE
1.1 This test method covers the determination of fracture toughness (KIc and optionally KIsi) of metallic materials under predominantly linear-elastic, plane-strain conditions using fatigue precracked specimens having a thickness of 1.6 mm (0.063 in.) or greater2 subjected to slowly, or in special (elective) cases rapidly, increasing crack-displacement force. Details of test apparatus, specimen configuration, and experimental procedure are given in the annexes. Two procedures are outlined for using the experimental data to calculate fracture toughness values:
1.1.1 The KIc test procedure is described in the main body of this test standard and is a mandatory part of the testing and results reporting procedure for this test method. The KIc test procedure is based on crack growth of up to 2 % percent of the specimen width. This can lead to a specimen size dependent rising fracture toughness resistance curve, with larger specimens producing higher fracture toughness results.
1.1.2 The KIsi test procedure is described in Appendix X1 and is an optional part of this test method. The KIsi test procedure is based on a fixed amount of crack extension of 0.5 mm, and as a result, KIsi is less sensitive to specimen size than KIc. This less size-sensitive fracture toughness, KIsi, is called size-insensitive throughout this test method. Appendix X1 contains an optional procedure for reinterpreting the force-displacement test record recorded as part of this test method to calculate the additional fracture toughness value, KIsi.
Note 1: Plane-strain fracture toughness tests of materials thinner than 1.6 mm (0.063 in.) that are sufficiently brittle (see 7.1) can be made using other types of specimens (1).3 There is no standard test method for such thin materials.
1.2 This test method is divided into two parts. The first part gives general recommendations and requirements for testing and includes specific requirements for the KI...
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Designation: E399 − 22
Standard Test Method for
Linear-Elastic Plane-Strain Fracture Toughness of Metallic
1
Materials
This standard is issued under the fixed designation E399; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 1.2 This test method is divided into two parts. The first part
gives general recommendations and requirements for testing
1.1 This test method covers the determination of fracture
and includes specific requirements for the K test procedure.
Ic
toughness (K and optionally K ) of metallic materials under
Ic Isi
The second part consists of Annexes that give specific infor-
predominantly linear-elastic, plane-strain conditions using fa-
mation on displacement gage and loading fixture design,
tigue precracked specimens having a thickness of 1.6 mm
2
special requirements for individual specimen configurations,
(0.063 in.) or greater subjected to slowly, or in special
and detailed procedures for fatigue precracking. Additional
(elective) cases rapidly, increasing crack-displacement force.
annexes are provided that give specific procedures for beryl-
Details of test apparatus, specimen configuration, and experi-
lium and rapid-force testing, and the K test procedure, which
mental procedure are given in the annexes. Two procedures are
Isi
outlined for using the experimental data to calculate fracture provides an optional additional analysis procedure for the test
toughness values:
data collected as part of the K test procedure.
Ic
1.1.1 The K test procedure is described in the main body of
Ic
1.3 General information and requirements common to all
this test standard and is a mandatory part of the testing and
specimen configurations:
results reporting procedure for this test method. The K test
Ic
Section
procedure is based on crack growth of up to 2 % percent of the
Referenced Documents 2
specimen width. This can lead to a specimen size dependent
Terminology 3
Stress-Intensity Factor 3.1.1
rising fracture toughness resistance curve, with larger speci-
Plane-Strain Fracture Toughness 3.1.2
mens producing higher fracture toughness results.
Crack Plane Orientation 3.1.4
1.1.2 The K test procedure is described in Appendix X1 Summary of Test Method 4
Isi
Significance and Use 5
and is an optional part of this test method. The K test
Isi
Significance 5.1
procedure is based on a fixed amount of crack extension of 0.5
Precautions 5.1.1 – 5.1.5
mm, and as a result, K is less sensitive to specimen size than
Practical Applications 5.2
Isi
Apparatus (see also 1.4) 6
K . This less size-sensitive fracture toughness, K , is called
Ic Isi
Tension Machine 6.1
size-insensitive throughout this test method. Appendix X1
Fatigue Machine 6.2
contains an optional procedure for reinterpreting the force- Loading Fixtures 6.3
Displacement Gage, Measurement 6.4
displacement test record recorded as part of this test method to
Specimen Size, Configurations, and Preparation (see 7
calculate the additional fracture toughness value, K .
Isi
also 1.5)
Specimen Size Estimates 7.1
NOTE 1—Plane-strain fracture toughness tests of materials thinner than
Standard and Alternative Specimen Configurations 7.2
1.6 mm (0.063 in.) that are sufficiently brittle (see 7.1) can be made using
3
Fatigue Crack Starter Notches 7.3.1
other types of specimens (1). There is no standard test method for such
Fatigue Precracking (see also 1.6) 7.3.2
thin materials.
Crack Extension Beyond Starter Notch 7.3.2.2
General Procedure 8
Specimen Measurements
Thickness 8.2.1
1
This test method is under the jurisdiction of ASTM Committee E08 on Fatigue
Width 8.2.2
and Fracture and is the direct responsibility of Subcommittee E08.07 on Fracture Crack Size 8.2.3
Mechanics. Crack Plane Angle 8.2.4
Specimen Testing
Current edition approved June 1, 2022. Published July 2022. Originally approved
Loading Rate 8.3
in 1970. Last previous edition approved in 2020 as E399 – 20a. DOI: 10.1520/
Test Record 8.4
E0399-22.
2
Calculation and Interpretation of Results 9
For additional information relating to the fracture toughness testing of
Test Record Analysis 9.1
aluminum alloys, see Practice B645.
3 P /P Validity Requirement 9.1.3
max Q
The boldface numbers in parentheses refer to the list of references at the end of
Specimen Size Validity Requirements 9.1.4
this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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E399 − 22
Section
Reporting 10
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E399 − 20a E399 − 22
Standard Test Method for
Linear-Elastic Plane-Strain Fracture Toughness of Metallic
1
Materials
This standard is issued under the fixed designation E399; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This test method covers the determination of fracture toughness (K and optionally K ) of metallic materials under
Ic Isi
predominantly linear-elastic, plane-strain conditions using fatigue precracked specimens having a thickness of 1.6 mm (0.063 in.)
2
or greater subjected to slowly, or in special (elective) cases rapidly, increasing crack-displacement force. Details of test apparatus,
specimen configuration, and experimental procedure are given in the annexes. Two procedures are outlined for using the
experimental data to calculate fracture toughness values:
1.1.1 The K test procedure is described in the main body of this test standard and is a mandatory part of the testing and results
Ic
reporting procedure for this test method. The K test procedure is based on crack growth of up to 2 % percent of the specimen
Ic
width. This can lead to a specimen size dependent rising fracture toughness resistance curve, with larger specimens producing
higher fracture toughness results.
1.1.2 The K test procedure is described in Appendix X1 and is an optional part of this test method. The K test procedure is
Isi Isi
based on a fixed amount of crack extension of 0.5 mm, and as a result, K is less sensitive to specimen size than K . This less
Isi Ic
size-sensitive fracture toughness, K , is called size-insensitive throughout this test method. Appendix X1 contains an optional
Isi
procedure for reinterpreting the force-displacement test record recorded as part of this test method to calculate the additional
fracture toughness value, K .
Isi
NOTE 1—Plane-strain fracture toughness tests of materials thinner than 1.6 mm (0.063 in.) that are sufficiently brittle (see 7.1) can be made using other
3
types of specimens (1). There is no standard test method for such thin materials.
1.2 This test method is divided into two parts. The first part gives general recommendations and requirements for testing and
includes specific requirements for the K test procedure. The second part consists of Annexes that give specific information on
Ic
displacement gage and loading fixture design, special requirements for individual specimen configurations, and detailed procedures
for fatigue precracking. Additional annexes are provided that give specific procedures for beryllium and rapid-force testing, and
the K test procedure, which provides an optional additional analysis procedure for the test data collected as part of the K test
Isi Ic
procedure.
1.3 General information and requirements common to all specimen configurations:
1
This test method is under the jurisdiction of ASTM Committee E08 on Fatigue and Fracture and is the direct responsibility of Subcommittee E08.07 on Fracture
Mechanics.
Current edition approved Dec. 1, 2020June 1, 2022. Published January 2021July 2022. Originally approved in 1970. Last previous edition approved in 2020 as
E399 – 20.E399 – 20a. DOI: 10.1520/E0399-20A.10.1520/E0399-22.
2
For additional information relating to the fracture toughness testing of aluminum alloys, see Practice B645.
3
The boldface numbers in parentheses refer to the list of references at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E399 − 22
Section
Referenced Documents 2
Terminology 3
Stress-Intensity Factor 3.1.1
Plane-Strain Fracture Toughness 3.1.2
Crack Plane Orientation 3.1.4
Summary of Test Method 4
Significance and Use 5
Significance 5.1
Precautions 5.1.1 – 5.1.5
Practical Applications 5.2
Apparatus (see also 1.4) 6
Tension Machine 6.1
Fatigue Machine 6.2
Loading Fixtures 6.3
Displacement Gage, Measurement 6.4
Specimen Size, Configurations, and Preparation (see 7
also 1.5)
Specimen Size Estimates 7.1
Standard and Alternative Specimen Configurations 7.2
Fatigue Crack Starter Notches 7.3.1
Fatigue Precracking (see also 1.6) 7.3.2
Crack Extension Beyond Starter Notch 7.3.2.2
General Procedu
...
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