ASTM E1820-08
(Test Method)Standard Test Method for Measurement of Fracture Toughness
Standard Test Method for Measurement of Fracture Toughness
SIGNIFICANCE AND USE
Assuming the presence of a preexisting, sharp, fatigue crack, the material fracture toughness values identified by this test method characterize its resistance to: (1) fracture of a stationary crack, (2) fracture after some stable tearing, (3) stable tearing onset, and (4) sustained stable tearing. This test method is particularly useful when the material response cannot be anticipated before the test. Application of procedures in Test Method E 1921 is recommended for testing ferritic steels that undergo cleavage fracture in the ductile-to-brittle transition.
These fracture toughness values may serve as a basis for material comparison, selection, and quality assurance. Fracture toughness can be used to rank materials within a similar yield strength range.
These fracture toughness values may serve as a basis for structural flaw tolerance assessment. Awareness of differences that may exist between laboratory test and field conditions is required to make proper flaw tolerance assessment.
The following cautionary statements are based on some observations.
Particular care must be exercised in applying to structural flaw tolerance assessment the fracture toughness value associated with fracture after some stable tearing has occurred. This response is characteristic of ferritic steel in the transition regime. This response is especially sensitive to material inhomogeneity and to constraint variations that may be induced by planar geometry, thickness differences, mode of loading, and structural details.
The J-R curve from bend-type specimens recommended by this test method (SE(B), C(T), and DC(T)) has been observed to be conservative with respect to results from tensile loading configurations.
The values of δc, δu, Jc, and Ju may be affected by specimen dimensions.
SCOPE
1.1 This test method covers procedures and guidelines for the determination of fracture toughness of metallic materials using the following parameters: K, J, and CTOD (δ). Toughness can be measured in the R-curve format or as a point value. The fracture toughness determined in accordance with this test method is for the opening mode (Mode I) of loading.
1.2 The recommended specimens are single-edge bend, [SE(B)], compact, [C(T)], and disk-shaped compact, [DC(T)]. All specimens contain notches that are sharpened with fatigue cracks.
1.2.1 Specimen dimensional (size) requirements vary according to the fracture toughness analysis applied. The guidelines are established through consideration of material toughness, material flow strength, and the individual qualification requirements of the toughness value per values sought.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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.
Note 1—Other standard methods for the determination of fracture toughness using the parameters K, J, and CTOD are contained in Test Methods E 399, E 813, E 1152, E 1290, and E 1737. This test method was developed to provide a common method for determining all applicable toughness parameters from a single test.
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Designation: E 1820 – 08a
Standard Test Method for
1
Measurement of Fracture Toughness
This standard is issued under the fixed designation E1820; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E21 Test Methods for Elevated Temperature Tension Tests
of Metallic Materials
1.1 This test method covers procedures and guidelines for
E399 Test Method for Linear-Elastic Plane-Strain Fracture
the determination of fracture toughness of metallic materials
Toughness K of Metallic Materials
using the following parameters: K, J, and CTOD (d). Tough- Ic
E1290 Test Method for Crack-Tip Opening Displacement
nesscanbemeasuredintheR-curveformatorasapointvalue.
(CTOD) Fracture Toughness Measurement
The fracture toughness determined in accordance with this test
E1823 Terminology Relating to Fatigue and Fracture Test-
method is for the opening mode (Mode I) of loading.
ing
1.2 The recommended specimens are single-edge bend,
E1921 Test Method for Determination of Reference Tem-
[SE(B)], compact, [C(T)], and disk-shaped compact, [DC(T)].
perature, T , for Ferritic Steels in the Transition Range
All specimens contain notches that are sharpened with fatigue o
E1942 Guide for Evaluating Data Acquisition Systems
cracks.
Used in Cyclic Fatigue and Fracture Mechanics Testing
1.2.1 Specimen dimensional (size) requirements vary ac-
cording to the fracture toughness analysis applied. The guide-
3. Terminology
lines are established through consideration of material tough-
3.1 Terminology E1823 is applicable to this test method.
ness, material flow strength, and the individual qualification
3.2 Definitions:
requirements of the toughness value per values sought.
−1
3.2.1 compliance [LF ], n—the ratio of displacement in-
1.3 The values stated in SI units are to be regarded as the
crement to force increment.
standard. The values given in parentheses are for information
3.2.2 crack displacement [L], n—the separation vector be-
only.
tween two points (on the surfaces of a deformed crack) that
1.4 This standard does not purport to address all of the
were coincident on the surfaces of an ideal crack in the
safety concerns, if any, associated with its use. It is the
undeformed condition.
responsibility of the user of this standard to establish appro-
3.2.2.1 Discussion—In this practice, displacement, v, is the
priate safety and health practices and determine the applica-
total displacement measured by clip gages or other devices
bility of regulatory limitations prior to use.
spanning the crack faces.
NOTE 1—Other standard methods for the determination of fracture
3.2.3 crack extension, Da [L], n—an increase in crack size.
toughness using the parameters K, J, and CTOD are contained in Test
−1 −2
3.2.4 crack-extension force, G [FL or FLL ], n—the
MethodsE399,E813,E1152,E1290,andE1737.Thistestmethodwas
elastic energy per unit of new separation area that is made
developed to provide a common method for determining all applicable
availableatthefrontofanidealcrackinanelasticsolidduring
toughness parameters from a single test.
a virtual increment of forward crack extension.
2. Referenced Documents
3.2.5 crack size, a [L], n—a lineal measure of a principal
2
planar dimension of a crack. This measure is commonly used
2.1 ASTM Standards:
in the calculation of quantities descriptive of the stress and
E4 Practices for Force Verification of Testing Machines
displacement fields, and is often also termed crack size or
E8 Test Methods for Tension Testing of Metallic Materials
depth.
3.2.5.1 Discussion—In practice, the value of a is obtained
1
This test method is under the jurisdiction ofASTM Committee E08 on Fatigue
from procedures for measurement of physical crack size, a ,
p
and Fracture and is the direct responsibility of Subcommittee E08.07 on Fracture
original crack size, a , and effective crack size, a , as appro-
o e
Mechanics.
Current edition approved Dec. 1, 2008. Published January 2009. Originally priate to the situation being considered.
approved in 1996. Last previous edition approved in 2008 as E1820–08.
3.2.6 crack-tip opening displacement (CTOD), d [L],
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
n—the crack displacement due to elastic and plastic deforma-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
tion at variously defined locations near the original crack tip.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
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...
This document is not anASTM standard and is intended only to provide the user of anASTM 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.
e1
Designation:E1820–06 Designation: E 1820 – 08
Standard Test Method for
1
Measurement of Fracture Toughness
This standard is issued under the fixed designation E1820; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1
e NOTE—Equation A3.11 was editorially corrected in May 2007.
1. Scope
1.1 This test method covers procedures and guidelines for the determination of fracture toughness of metallic materials using
the following parameters: K, J, and CTOD (d).Toughness can be measured in the R-curve format or as a point value.The fracture
toughness determined in accordance with this test method is for the opening mode (Mode I) of loading.
1.2 The recommended specimens are single-edge bend, [SE(B)], compact, [C(T)], and disk-shaped compact, [DC(T)]. All
specimens contain notches that are sharpened with fatigue cracks.
1.2.1 Specimen dimensional (size) requirements vary according to the fracture toughness analysis applied. The guidelines are
established through consideration of material toughness, material flow strength, and the individual qualification requirements of
the toughness value per values sought.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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.
NOTE 1—Other standard methods for the determination of fracture toughness using the parameters K, J, and CTOD are contained in Test Methods
E399, E813, E1152, E1290, and E1737. This test method was developed to provide a common method for determining all applicable toughness
parameters from a single test.
2. Referenced Documents
2
2.1 ASTM Standards:
E4 Practices for Force Verification of Testing Machines
E8 Test Methods for Tension Testing of Metallic Materials
E21 Test Methods for Elevated Temperature Tension Tests of Metallic Materials
E399 Test Method for Linear-Elastic Plane-Strain Fracture Toughness K of Metallic Materials
Ic
E1290 Test Method for Crack-Tip Opening Displacement (CTOD) Fracture Toughness Measurement
E1823 Terminology Relating to Fatigue and Fracture Testing
E1921 Test Method for Determination of Reference Temperature, T , for Ferritic Steels in the Transition Range
o
E1942 Guide for Evaluating Data Acquisition Systems Used in Cyclic Fatigue and Fracture Mechanics Testing
3. Terminology
3.1 Terminology E1823 is applicable to this test method.
3.2 Definitions:
−1
3.2.1 compliance [LF ], n— the ratio of displacement increment to force increment.
3.2.2 crack displacement [L], n—the separation vector between two points (on the surfaces of a deformed crack) that were
coincident on the surfaces of an ideal crack in the undeformed condition.
3.2.2.1 Discussion—Inthispractice,displacement,v,isthetotaldisplacementmeasuredbyclipgagesorotherdevicesspanning
the crack faces.
3.2.3 crack extension, Da [L], n—an increase in crack size.
−1 −2
3.2.4 crack-extension force, G [FL or FLL ], n—the elastic energy per unit of new separation area that is made available
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 July 1, 2006. Published July 2006. Originally approved in 1996. Last previous edition approved in 2005 as E1820–05a.
e1
Current edition approved April 1, 2008. Published April 2008. Originally approved in 1996. Last previous edition approved in 2006 as E1820–06 .
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.ForAnnualBookofASTMStandards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
E1820–08
at the front of an ideal crack in an elastic solid during a virtual increment of forward crack extension.
3.2.5 crack size, a [L], n—a lineal measure of a principal planar dimension of a crack. This measure is commo
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