ASTM E1922-04(2010)e1
(Test Method)Standard Test Method for Translaminar Fracture Toughness of Laminated and Pultruded Polymer Matrix Composite Materials
Standard Test Method for Translaminar Fracture Toughness of Laminated and Pultruded Polymer Matrix Composite Materials
SIGNIFICANCE AND USE
The parameter KTL determined by this test method is a measure of the resistance of a polymer matrix composite laminate to notch-tip damage and effective translaminar crack growth under opening mode loading. The result is valid only for conditions in which the damage zone at the notch tip is small compared with the notch length and the in-plane specimen dimensions.
This test method can serve the following purposes. In research and development, KTL data can quantitatively establish the effects of fiber and matrix variables and stacking sequence of the laminate on the translaminar fracture resistance of composite laminates. In acceptance and quality control specifications, KTL data can be used to establish criteria for material processing and component inspection.
The translaminar fracture toughness, KTL, determined by this test method may be a function of the testing speed and temperature. This test method is intended for room temperature and quasi-static conditions, but it can apply to other test conditions provided that the requirements of 9.2 and 9.3 are met. Application of KTL in the design of service components should be made with awareness that the test parameters specified by this test may differ from service conditions, possibly resulting in a different material response than that seen in service.
Not all types of laminated polymer matrix composite materials experience the contained notch-tip damage and effective translaminar crack growth of concern in this test method. For example, the notch-tip damage may be more extensive and may not be accompanied by any significant amount of effective translaminar crack growth. Typically, lower strength composite materials and those with a significant proportion of reinforcing fibers aligned in a direction perpendicular to the notch axis may not experience the contained notch-tip damage required for a valid test.
SCOPE
1.1 This test method covers the determination of translaminar fracture toughness, KTL, for laminated and pultruded polymer matrix composite materials of various ply orientations using test results from monotonically loaded notched specimens.
1.2 This test method is applicable to room temperature laboratory air environments.
1.3 Composite materials that can be tested by this test method are not limited by thickness or by type of polymer matrix or fiber, provided that the specimen sizes and the test results meet the requirements of this test method. This test method was developed primarily from test results of various carbon fiber – epoxy matrix laminates and from additional results of glass fiber – epoxy matrix, glass fiber-polyester matrix pultrusions and carbon fiber – bismaleimide matrix laminates (1-4, 6, 7).
1.4 A range of eccentrically loaded, single-edge-notch tension, ESE(T), specimen sizes with proportional planar dimensions is provided, but planar size may be variable and adjusted, with associated changes in the applied test load. Specimen thickness is a variable, independent of planar size.
1.5 Specimen configurations other than those contained in this test method may be used, provided that stress intensity calibrations are available and that the test results meet the requirements of this test method. It is particularly important that the requirements discussed in 5.1 and 5.4 regarding contained notch-tip damage be met when using alternative specimen configurations.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 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 to determine the applicability of regulatory limitations prior to use.
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Designation: E1922 − 04(Reapproved 2010)
Standard Test Method for
Translaminar Fracture Toughness of Laminated and
Pultruded Polymer Matrix Composite Materials
This standard is issued under the fixed designation E1922; 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.
ε NOTE—1.6 and 3.2.1 were editorially updated in January 2011.
1. Scope 1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers the determination of translami-
responsibility of the user of this standard to establish appro-
nar fracture toughness, K , for laminated and pultruded
TL
priate safety and health practices and to determine the
polymer matrix composite materials of various ply orientations
applicability of regulatory limitations prior to use.
using test results from monotonically loaded notched speci-
mens.
2. Referenced Documents
1.2 This test method is applicable to room temperature
2.1 ASTM Standards:
laboratory air environments.
D883 Terminology Relating to Plastics
1.3 Composite materials that can be tested by this test
D3039/D3039M Test Method for Tensile Properties of Poly-
method are not limited by thickness or by type of polymer
mer Matrix Composite Materials
matrix or fiber, provided that the specimen sizes and the test
D3878 Terminology for Composite Materials
results meet the requirements of this test method. This test
D5229/D5229M TestMethodforMoistureAbsorptionProp-
method was developed primarily from test results of various
erties and Equilibrium Conditioning of Polymer Matrix
carbon fiber – epoxy matrix laminates and from additional
Composite Materials
results of glass fiber – epoxy matrix, glass fiber-polyester
D5528 TestMethodforModeIInterlaminarFractureTough-
matrix pultrusions and carbon fiber – bismaleimide matrix
ness of Unidirectional Fiber-Reinforced Polymer Matrix
laminates (1-4, 5, 6).
Composites
E4 Practices for Force Verification of Testing Machines
1.4 A range of eccentrically loaded, single-edge-notch
E6 Terminology Relating to Methods of Mechanical Testing
tension, ESE(T), specimen sizes with proportional planar
E83 Practice for Verification and Classification of Exten-
dimensions is provided, but planar size may be variable and
someter Systems
adjusted, with associated changes in the applied test load.
E399 Test Method for Linear-Elastic Plane-Strain Fracture
Specimen thickness is a variable, independent of planar size.
Toughness K of Metallic Materials
Ic
1.5 Specimen configurations other than those contained in
E1823 TerminologyRelatingtoFatigueandFractureTesting
this test method may be used, provided that stress intensity
calibrations are available and that the test results meet the
3. Terminology
requirements of this test method. It is particularly important
3.1 Definitions:
that the requirements discussed in 5.1 and 5.4 regarding
3.1.1 Terminology E6, E1823, and D3878 are applicable to
contained notch-tip damage be met when using alternative
this test method.
specimen configurations.
3.2 Definitions of Terms Specific to This Standard:
1.6 The values stated in SI units are to be regarded as
3.2.1 notch-mouth displacement, V [L]—the Mode I (also
n
standard. No other units of measurement are included in this
called opening mode) component of crack or notch displace-
standard.
ment due to elastic and permanent deformation. The displace-
ment is measured across the mouth of the notch on the
This test method is under the jurisdiction ofASTM Committee E08 on Fatigue
and Fracture and is the direct responsibility of Subcommittee E08.05 on Cyclic specimen edge (see Fig. 1).
Deformation and Fatigue Crack Formation.
Current edition approved Oct. 1, 2010. Published January 2011. Originally
approved in 1997. Last previous edition approved in 2004 as E1922–04. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/E1922-04R10E01. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
The boldface numbers in parentheses refer to the list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E1922 − 04 (2010)
FIG. 1 Test Arrangement for Translaminar Fracture Toughness Tests
3.2.2 notch length, a [L]—the distance from a reference samples and for samples with a significant proportion of the
n
plane to the front of the machined notch. The reference plane near surface reinforcing fibers aligned parallel to the direction
depends on the specimen form, and normally is taken to be of the notch.
eithertheboundary,oraplanecontainingeithertheloadlineor
the centerline of a specimen or plate. The reference plane is 5. Significance and Use
defined prior to specimen deformation (see Fig. 2).
5.1 The parameter K determined by this test method is a
TL
3.2.3 normalized notch size, a /W [nd]—the ratio of notch
measure of the resistance of a polymer matrix composite
n
length, a , to specimen width, W.
laminate to notch-tip damage and effective translaminar crack
n
growth under opening mode loading. The result is valid only
3.2.4 For additional information, see Terminology D883
for conditions in which the damage zone at the notch tip is
and Test Methods D3039/D3039M, D5229/D5229M, and
small compared with the notch length and the in-plane speci-
D5528.
men dimensions.
4. Summary of Test Method
5.2 This test method can serve the following purposes. In
4.1 This test method involves tension testing of eccentri- research and development, K data can quantitatively estab-
TL
cally loaded, single-edge-notch, ESE(T), specimens in opening lish the effects of fiber and matrix variables and stacking
mode loading. Load versus displacement across the notch at sequenceofthelaminateonthetranslaminarfractureresistance
the specimen edge, V , is recorded. The load corresponding to of composite laminates. In acceptance and quality control
n
aprescribedincreaseinnormalizednotchlengthisdetermined, specifications, K data can be used to establish criteria for
TL
using the load-displacement record. The translaminar fracture material processing and component inspection.
toughness, K , is calculated from this load using equations
TL
5.3 Thetranslaminarfracturetoughness,K ,determinedby
TL
that have been established on the basis of elastic stress analysis
this test method may be a function of the testing speed and
of the modified single-edge notched specimen.
temperature.Thistestmethodisintendedforroomtemperature
4.2 The validity of translaminar fracture toughness, K , and quasi-static conditions, but it can apply to other test
TL
determined by this test method depends on maintaining a conditions provided that the requirements of 9.2 and 9.3 are
relatively contained area of damage at the notch tip. To met. Application of K in the design of service components
TL
maintain this suitable notch-tip condition, the allowed increase should be made with awareness that the test parameters
in notch-mouth displacement near the maximum load point of specified by this test may differ from service conditions,
the tests is limited to a small value. Small increases in possiblyresultinginadifferentmaterialresponsethanthatseen
notch-mouth displacement are more likely for relatively thick in service.
NOTE 1—All dimensions +/– 0.01 W, except as noted.
NOTE 2—A surfaces perpendicular and parallel as applicable within 0.01 W.
FIG. 2 Translaminar Fracture Toughness Test Specimen
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E1922 − 04 (2010)
5.4 Not all types of laminated polymer matrix composite less than 0.015 W gives consistent results regardless of notch
materials experience the contained notch-tip damage and tip profile. A diamond impregnated copper slitting saw or a
effective translaminar crack growth of concern in this test jewelers saw have been found to work well. Use caution to
method. For example, the notch-tip damage may be more prevent splitting or delamination of the surface plies near the
extensive and may not be accompanied by any significant notch tip.
amount of effective translaminar crack growth. Typically,
8. Procedure
lower strength composite materials and those with a significant
proportion of reinforcing fibers aligned in a direction perpen-
8.1 Number of Tests— It is required that enough tests be
dicular to the notch axis may not experience the contained
performed to obtain three valid replicate test results for each
notch-tip damage required for a valid test.
material condition. If material variations are expected, five
tests are required.
6. Apparatus
8.2 Specimen Measurement—Three specimen measure-
6.1 Loading—Specimens shall be loaded in a testing ma-
ments are necessary to calculate applied K: notch length, a ;
n
chine that has provision for simultaneous recording of the load
thickness, B; and width, W. Complete separation of the
applied to the specimen and the resulting notch-mouth dis-
specimen into two pieces often occurs during a test, so it is
placement. A typical arrangement is shown in Fig. 1. Pin-
required that the specimen measurements be done prior to
loading clevises of the type used inTest Method E399 are used
testing. Also, exercise care to prevent injury to test personnel.
to apply the load to the specimen. The accuracies of the load
8.2.1 Measurethenotchlength, a ,tothenearest0.1mmon
n
measuring and recording devices should be such that load can
each side of the specimen. Use the average of the two notch
be determined with an accuracy of 61 %. (For additional
length measurements in the calculations of applied K.
information see Practices E4).
8.2.2 Measurethethickness, B,tothenearest0.002 W,atno
6.2 Displacement Gage—Adisplacement gage shall be used
fewer than three equally spaced positions around the notch.
tomeasurethedisplacementatthenotchmouthduringl
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