ASTM E1922/E1922M-22

Standard Test Method for Translaminar Fracture Toughness of Laminated and Pultruded Polymer Matrix Composite Materials

SIGNIFICANCE AND USE
5.1 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. Alternately, for materials exhibiting distributed damage in a larger volume, observed force-displacement and discrete damage events are still valid structural responses for certain specific engineering applications.  
5.2 This test method can serve the following purposes. In research and development, (a) 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; and (b) quantified distributed damage measurements can be used to validate progressive composite damage models. In structural design, KTL data can, within the constraints of the specimen geometry and loading, be used to assess composite laminate resistance to damage growth from edge flaws and notches.  
5.3 The translaminar fracture toughness,  KTL, as well as distributed damage observations, 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 13.2 and 13.3 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. Distributed damage observations are also limited to the material and geometry tested, but may be more generally applied to a variety of structural analysis validation applications.  
5.4 Not all types of laminated polymer matrix...
SCOPE
1.1 This test method covers the determination of translaminar fracture toughness, KTL, for laminated, molded, or pultruded polymer matrix composite materials of various fiber orientations using test results from monotonically loaded notched specimens. If the material response is such that the KTL calculation is not valid, alternate reporting methods are provided.  
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, 5, 6).2  
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. 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 in conjunction with the KTL calculation.  
1.6 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.6.1 Within the text, the inch-pound units are shown ...

General Information

• Status: Published
• Publication Date: 30-Apr-2022
• ICS: 83.140.20 - Laminated sheets
• Technical Committee: D30 - Composite Materials
• Drafting Committee: D30.05 - Structural Test Methods

Relations

• Refers: ASTM E1823-24a - Standard Terminology Relating to Fatigue and Fracture Testing
• Effective Date: 15-Feb-2024
• Refers: ASTM E1823-24 - Standard Terminology Relating to Fatigue and Fracture Testing
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-24 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-23 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2023
• Refers: ASTM E456-13a(2022)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022
• Refers: ASTM D5229/D5229M-20 - Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials
• Effective Date: 01-Mar-2020
• Refers: ASTM E1823-20 - Standard Terminology Relating to Fatigue and Fracture Testing
• Effective Date: 01-Feb-2020
• Refers: ASTM D883-20 - Standard Terminology Relating to Plastics
• Effective Date: 01-Jan-2020
• Refers: ASTM D3878-19a - Standard Terminology for Composite Materials
• Effective Date: 15-Oct-2019
• Refers: ASTM D883-19c - Standard Terminology Relating to Plastics
• Effective Date: 01-Aug-2019
• Refers: ASTM D3878-19 - Standard Terminology for Composite Materials
• Effective Date: 15-Apr-2019
• Refers: ASTM D883-19a - Standard Terminology Relating to Plastics
• Effective Date: 15-Apr-2019
• Refers: ASTM D883-19 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2019
• Refers: ASTM D883-18a - Standard Terminology Relating to Plastics
• Effective Date: 01-Dec-2018
• Refers: ASTM D883-18 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2018

Overview

ASTM E1922/E1922M-22 establishes a standard test method for determining the translaminar fracture toughness (KTL) of laminated and pultruded polymer matrix composite materials. This method is integral for evaluating how composite laminates resist notch-tip damage and crack growth under opening mode loading. It applies to composites of varying fiber orientations, thicknesses, and matrix types, using results from tension testing of monotonically loaded, notched specimens at room temperature.

Fracture toughness measurements are essential for research and development, structural design, and quality control in industries that rely on the structural integrity and durability of composite materials, such as aerospace, automotive, wind energy, and civil engineering.

Key Topics

• Translaminar Fracture Toughness (KTL):

  • Provides a quantitative measure of a composite laminate's resistance to crack growth and propagation from notches under tensile stress.
  • KTL validity relies on keeping the damage zone at the notch tip small compared to the notch length and in-plane specimen dimensions.

• Applicability:

  • Suited to a broad range of composite materials including carbon fiber-epoxy, glass fiber-epoxy, glass fiber-polyester pultrusions, and carbon fiber-bismaleimide laminates.
  • Not limited by thickness, polymer matrix, or fiber type, provided the specimen meets dimensional and test requirements.

• Test Configurations and Environments:

  • Involves eccentrically loaded, single-edge-notch tension (ESE(T)) specimens.
  • Applicable to room temperature laboratory environments; other conditions may apply if requirements are met.

• Damage Characterization:

  • If extensive distributed damage occurs, the test still provides valid structural response data, such as force-displacement behavior and damage events, useful for validating composite damage models.

• Specimen Requirements:

  • Multidirectional fiber orientation, accurate specimen geometry, and precise notch preparation are critical for reliable results.
  • Requires careful documentation of material properties, fabrication methods, and test conditions.

• Reporting:

  • Comprehensive reporting of specimen preparation, testing procedure, material identification, notch dimensions, environmental data, and statistical measures of fracture toughness and damage events.

Applications

• Research & Development:

  • Enables quantification of how fiber and matrix variables or stacking sequences influence the fracture resistance of polymer matrix composites.
  • Supports the validation of progressive damage models for new composite formulations and structures.

• Structural Design:

  • Provides critical data to assess the resistance of composite laminates to edge flaws and notches, supporting damage tolerance criteria in structural components.
  • Facilitates safer, more efficient design of lightweight structures used in transportation, energy, and infrastructure.

• Quality Control & Specification:

  • Ensures manufacturing consistency by establishing acceptance criteria for composite panels and components.
  • Helps identify material or fabrication process variations that affect structural performance.

• Validation of Numerical and Analytical Models:

  • Force-displacement and discrete damage data can be used to validate finite element or damage mechanics models, improving predictive maintenance and design optimization.

Related Standards

• ASTM D3039/D3039M - Test Method for Tensile Properties of Polymer Matrix Composite Materials
• ASTM D3171 - Test Methods for Constituent Content of Composite Materials
• ASTM D5528/D5528M - Test Method for Mode I Interlaminar Fracture Toughness of Unidirectional Fiber-Reinforced Composites
• ASTM D5687/D5687M - Guide for Preparation of Flat Composite Panels
• ASTM E399 - Test Method for Linear-Elastic Plane-Strain Fracture Toughness of Metallic Materials
• ASTM D792 - Density and Specific Gravity (Relative Density) of Plastics by Displacement

ASTM E1922/E1922M-22 is a key resource for anyone involved in the testing, design, or certification of polymer matrix composite materials, ensuring reliable and comparable assessment of translaminar fracture properties across the global composites industry. For implementation and full technical guidance, always refer to the latest official ASTM edition.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1922/E1922M − 22
Standard Test Method for
Translaminar Fracture Toughness of Laminated and
Pultruded Polymer Matrix Composite Materials
ThisstandardisissuedunderthefixeddesignationE1922/E1922M;thenumberimmediatelyfollowingthedesignationindicatestheyear
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.
1. Scope system shall be used independently of the other, and values
from the two systems shall not be combined.
1.1 This test method covers the determination of translami-
1.6.1 Within the text, the inch-pound units are shown in
nar fracture toughness, K , for laminated, molded, or pul-
TL
brackets.
truded polymer matrix composite materials of various fiber
1.7 This standard does not purport to address all of the
orientations using test results from monotonically loaded
safety concerns, if any, associated with its use. It is the
notchedspecimens.Ifthematerialresponseissuchthatthe K
TL
responsibility of the user of this standard to establish appro-
calculation is not valid, alternate reporting methods are pro-
priate safety, health, and environmental practices and deter-
vided.
mine the applicability of regulatory limitations prior to use.
1.2 This test method is applicable to room temperature
1.8 This international standard was developed in accor-
laboratory air environments.
dance with internationally recognized principles on standard-
1.3 Composite materials that can be tested by this test
ization established in the Decision on Principles for the
method are not limited by thickness or by type of polymer
Development of International Standards, Guides and Recom-
matrix or fiber, provided that the specimen sizes and the test
mendations issued by the World Trade Organization Technical
results meet the requirements of this test method. This test
Barriers to Trade (TBT) Committee.
method was developed primarily from test results of various
carbon fiber – epoxy matrix laminates and from additional
2. Referenced Documents
results of glass fiber – epoxy matrix, glass fiber-polyester
2.1 ASTM Standards:
matrix pultrusions and carbon fiber – bismaleimide matrix
D792 Test Methods for Density and Specific Gravity (Rela-
laminates (1-4, 5, 6).
tive Density) of Plastics by Displacement
1.4 A range of eccentrically loaded, single-edge-notch
D883 Terminology Relating to Plastics
tension, ESE(T), specimen sizes with proportional planar
D3039/D3039M Test Method for Tensile Properties of Poly-
dimensions is provided, but planar size may be variable and
mer Matrix Composite Materials
adjusted, with associated changes in the applied test load.
D3171 Test Methods for Constituent Content of Composite
Specimen thickness is a variable, independent of planar size.
Materials
D3878 Terminology for Composite Materials
1.5 Specimen configurations other than those contained in
D5229/D5229M TestMethodforMoistureAbsorptionProp-
this test method may be used. It is particularly important that
erties and Equilibrium Conditioning of Polymer Matrix
the requirements discussed in 5.1 and 5.4 regarding contained
Composite Materials
notch-tip damage be met when using alternative specimen
D5528/D5528M Test Method for Mode I Interlaminar Frac-
configurations in conjunction with the K calculation.
TL
ture Toughness of Unidirectional Fiber-Reinforced Poly-
1.6 Units—The values stated in either SI units or inch-
mer Matrix Composites
pound units are to be regarded separately as standard. The
D5687/D5687M Guide for Preparation of Flat Composite
values stated in each system are not necessarily exact equiva-
Panels with Processing Guidelines for Specimen Prepara-
lents; therefore, to ensure conformance with the standard, each
tion
E4 Practices for Force Calibration and Verification of Test-
This test method is under the jurisdiction of ASTM Committee D30 on
ing Machines
Composite Materials and is the direct responsibility of Subcommittee D30.05 on
Structural Test Methods.
Current edition approved May 1, 2022. Published June 2022 by Committee D30.
Originally approved in 1997 by Committee E08. Last previous edition approved in For referenced ASTM standards, visit the ASTM website, www.astm.org, or
2015 as E1922 – 04(2015) by Committee D30. DOI: 10.1520/E1922_E1922M-22. contact ASTM Customer Service at [e-mail]. 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
E1922/E1922M − 22
E6 Terminology Relating to Methods of Mechanical Testing 3.2.4 notch length [L], n—the distance from a reference
E83 Practice for Verification and Classification of Exten- plane to the front of the machined notch. The reference plane
someter Systems depends on the specimen form, and normally is taken to be
E122 Practice for Calculating Sample Size to Estimate,With eithertheboundary,oraplanecontainingeithertheloadlineor
Specified Precision, the Average for a Characteristic of a the centerline of a specimen or plate. The reference plane is
Lot or Process defined prior to specimen deformation (see Fig. 2).
E177 Practice for Use of the Terms Precision and Bias in
3.2.5 For additional information, see Terminology D883
ASTM Test Methods
and Test Methods D3039/D3039M, D5229/D5229M, and
E399 Test Method for Linear-Elastic Plane-Strain Fracture
D5528/D5528M.
Toughness of Metallic Materials
3.3 Symbols:
E456 Terminology Relating to Quality and Statistics
a —notch length
n
E1823 TerminologyRelatingtoFatigueandFractureTesting
B—specimen thickness
CV—coefficient of variation statistic of a sample population
3. Terminology
for a given property (in percent)
3.1 Definitions:
K—applied stress intensity factor
3.1.1 Terminology D3878 defines terms relating to compos-
K —translaminar fracture toughness
TL
ite materials. Terminology D883 defines terms relating to
P—applied force
plastics. Terminology E6 defines terms relating to mechanical
P —maximum applied force achieved during test
max
testing. Terminology E1823 defines terms relating to fracture
S —standard deviation statistic of a sample population for
n-1
testing. Terminology E456 and Practice E177 define terms
a given property
relating to statistics. In the event of a conflict between terms,
V —notch-mouth displacement
n
Terminology D3878 shall have precedence over the other
W—specimen width
standards.
x —test result for an individual specimen from the sample
i
population for a given property
3.2 Definitions of Terms Specific to This Standard:
x¯—mean or average (estimate of mean) of a sample popu-
3.2.1 If the term represents a physical quantity, its analyti-
lation for a given property
cal dimensions are stated immediately following the term (or
α—normalized notch size
letter symbol) in fundamental dimension form, using the
following ASTM standard symbology for fundamental
4. Summary of Test Method
dimensions, shown within square brackets: [M] for mass, [L]
for length, [T] for time, [θ] for thermodynamic temperature,
4.1 This test method involves tension testing of eccentri-
and [nd] for non-dimensional quantities. Use of these symbols
cally loaded, single-edge-notch, ESE(T), specimens in opening
is restricted to analytical dimensions when used with square
mode loading. Force versus displacement across the notch at
brackets, as the symbols may have other definitions when used
the specimen edge, V , is recorded. The force corresponding to
n
without the brackets.
aprescribedincreaseinnormalizednotchlengthisdetermined,
3.2.2 normalized notch size [nd], n—the ratio of notch
using the force-displacement record. The translaminar fracture
length, a , to specimen width, W.
n
toughness, K , is calculated from this force using equations
TL
3.2.3 notch-mouth displacement [L], n—the Mode I (also that have been established on the basis of elastic stress analysis
called opening mode) component of crack or notch displace- of the modified single-edge notched specimen. When the
ment due to elastic and permanent deformation. The displace- assumptions upon which the K calculation is based are
TL
ment is measured across the mouth of the notch on the violated, results are instead reported in terms of applied
specimen edge (see Fig. 1). force/width, geometry, and observed distributed damage.
FIG. 1 Test Arrangement for Translaminar Fracture Toughness Tests
E1922/E1922M − 22
NOTE 1—All dimensions +/– 0.01 W, except as noted.
NOTE 2—All surfaces perpendicular and parallel as applicable within 0.01 W.
FIG. 2 Translaminar Fracture Toughness Test Specimen
4.2 The validity of translaminar fracture toughness, K , 5.3 The translaminar fracture toughness, K , as well as
TL TL
determined by this test method depends on maintaining a distributed damage observations, determined by this test
relatively contained area of damage at the notch tip. To methodmaybeafunctionofthetestingspeedandtemperature.
maintain this suitable notch-tip condition, the allowed increase This test method is intended for room temperature and quasi-
in notch-mouth displacement near the maximum force point of static conditions, but it can apply to other test conditions
the tests is limited to a small value. Small increases in provided that the requirements of 13.2 and 13.3 are met.
notch-mouth displacement are more likely for relatively thick Application of K in the design of service components should
TL
samples and for samples with a significant proportion of the be made with awareness that the test parameters specified by
near surface reinforcing fibers aligned parallel to the direction this test may differ from service conditions, possibly resulting
of the notch, or inherently brittle material response, or both. in a different material response than that seen in service.
Distributed damage observations are also limited to the mate-
4.3 Formaterialresponseinwhichthedamageisnotlimited
rial and geometry tested, but may be more generally applied to
to the local crack tip region, this test method results in a
a variety of structural analysis validation applications.
structural failure response that is strongly dependent on speci-
men geometric details (in addition to length, width, and notch
5.4 Not all types of laminated polymer matrix composite
geometry) such as fiber orientations, stacking sequence if
materials experience the contained notch-tip damage and
laminated,weavearchitectureifwoven,manufacturingprocess
effective translaminar crack growth of concern in this test
if liquid-molded or containing discontinuous fibers, etc. In
method. In such circumstances, the force-displacement and
thesecases,therelevantreporteddataisnot K butratherthen
discrete damage observations – not K – shall be used.
TL
TL
globalobservedstructuralresponseofthecoupon,forexample,
5.5 The reporting section requires items that tend to influ-
the force-displacement history as a function of observed
ence translaminar fracture toughness and discrete damage
damage events (crack branching, delaminations, local fiber
progression to be reported; these include the following:
failures, etc).
material, methods of material fabrication, accuracy of lay-up
orientation, laminate stacking sequence and overall thickness,
5. Significance and Use
specimen geometry, specimen preparation, specimen
5.1 The parameter K determined by this test method is a
TL
conditioning, environment of testing, void content, volume
measure of the resistance of a polymer matrix composite
percent reinforcement, size and method of notch preparation,
laminate to notch-tip damage and effective translaminar crack
specimen/fixture alignment, and speed of testing.
growth under opening mode loading. The result is valid only
for conditions in which the damage zone at the notch tip is
6. Interferences
small compared with the notch length and the in-plane speci-
6.1 Material and Specimen Preparation—Poormaterialfab-
men dimensions. Alternately, for materials exhibiting distrib-
rication practices, lack of control of fiber alignment, and
uted damage in a larger volume, observed force-displacement
damage induced by improper specimen machining are known
and discrete damage events are still valid structural responses
causes of high material data scatter in composites in general.
for certain specific engineering applications.
Important aspects of specimen preparation that contribute to
5.2 This test method can serve the following purposes. In
data scatter include thickness variation, out-of-plane curvature,
research and development, (a) K data can quantitatively
TL
surface roughness, and failure to meet the dimensional and
establish the effects of fiber and matrix variables and stacking
squareness tolerances (parallelism and perpendicularity) speci-
sequenceofthelaminateonthetranslaminarfractureresistance
fied in 8.2.2.
of composite laminates; and (b) quantified distributed damage
measurements can be used to validate progressive composite 6.2 Notch Preparation—Because of the dominating pres-
damage models. In structural design, K data can, within the ence of the notch, results from this test method are relatively
TL
constraints of the specimen geometry and loading, be used to insensitive to parameters that would be of concern in an
assess composite laminate resistance to damage growth from unnotched tensile property test. However, since the notch
edge flaws and notches. dominates the response, consistent preparation of the notch is
E1922/E1922M − 22
important to meaningful results. Damage caused by notch indicate the force with an accuracy over the force range(s) of
preparation can affect the calculated translaminar fracture interest of within 61 % of the indicated value.
toughness.
7.4 Displacement Gage—Adisplacement gage shall be used
6.3 Geometry—Results are affected by the ratio of notch tomeasurethedisplacementatthenotchmouthduringloading.
length to specimen width, as well as the ratio of notch width to
An electronic displacement gage of the type described in Test
specimen width. The ratios should be maintained as specified Method E399 can provide a highly sensitive indicator of
in 8.1, unless the experiment is investigating the influence of
notch-mouth displacement for this purpose. The gage is at-
these ratios. tached to the specimen using knife edges affixed to the
specimen or integral knife edges machined into the specimen.
6.4 Material Behavior—The inherent damage progression
Integral knife edges may not be suitable for relatively low
from the relatively blunt machined notch in this test specimen
strength materials. Other types of gages and attachments may
design determines whether or not the K calculation is valid.
TL
be used if it can be demonstrated that they will accomplish the
It is the joint responsibility of the test requester and test
same result.The accuracies of the displacement measuring and
operator to determine the validity of the calculated fracture
recording devices should be such that the displacement can be
toughness value and report the final data in an appropriate
determined with an accuracy of 61 %. (For additional
manner.
information, see Practice E83.)
6.5 System Alignment—Errors can result if the test fixture is
7.5 Full-Field Strain Measurement Equipment—For quanti-
not centered with respect to the loading axis of the test
fication of distributed discrete damage events remote from the
machine.
notch tip, full field strain measurement methods such a Digital
Image Correlation (DIC), high-speed photography, Moire
7. Apparatus
Fringe methods, etc. may be required. Required resolution of
7.1 Micrometers and Calipers—Amicrometer witha4to8
such methods are dependent on damage events being measured
mm [0.16 to 0.32 in.] nominal diameter ball-interface or a flat
and shall be determined by the test requester for specific
anvil interface shall be used to measure the specimen thick-
materials and specimen geometries.
ness. A ball interface is recommended for thickness measure-
7.6 Data Acquisition Equipment—Equipment capable of
ments when at least one surface is irregular (for example, a
recording force and notch mouth displacement is required.
coarse peel ply surface which is neither smooth nor flat). A
Full-field strain measurement is optional.
micrometer or caliper with a flat anvil interface shall be used
for measuring length, width, and other machined surface
8. Sampling and Test Specimens
dimensions. The use of alternative measurement devices is
permitted if specified (or agreed to) by the test requestor and
8.1 Sampling—It is required that enough tests be performed
reported by the testing laboratory. The accuracy of the instru-
to obtain three valid replicate test results for each material
ment(s) shall be suitable for reading to within1%ofthe
condition. If material variations are expected, five tests are
specimen dimensions. For typical specimen geometries, an
required. For statistically significant data, the procedures
instrument with an accuracy of 60.0025 mm [60.0001 in.] is
outlined in Practice E122 should be consulted. The method of
adequateforthicknessmeasurements,whileaninstrumentwith
sampling shall be reported.
an accuracy of 60.025 mm [60.001 in.] is adequate for
8.2 Geometry:
measurement of length, width, other machined surface dimen-
8.2.1 Stacking Sequence—The specimen shall have multidi-
sions.
rectional fiber orientations (fibers oriented in a minimum of
7.2 Test Fixture—Pin-loading clevises of the type used in
two directions), with the 0° fiber orientation aligned with the
TestMethodE399shallbeusedtoapplyforcetothespecimen.
lengthwise (long) dimension.Athickness as small as 2 mm has
A typical arrangement is shown in Fig. 1.
been found to work well. However, too small a thickness can
7.3 Testing Machine—The testing machine shall be in con-
cause out-of-plane buckling, which invalidates the test. The 0°
formance with Practices E4, and shall satisfy the following
fiber orientation of the specimen before testing shall be aligned
requirements:
to within 2° of the intended loading axis. For example, a K
TL
7.3.1 Testing Machine Configuration—The testing machine test of a [0/90] laminate would involve the testing of a 20 ply
5S
shall have both an essentially stationary head and a movable
specimen with the fibers in the 0° plies aligned within 2° of the
head. loading axis of the specimen.
7.3.2 Drive Mechanism—The testing machine drive mecha-
8.2.2 Specimen Configuration—The required test and speci-
nism shall be capable of imparting to the movable head a
...

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: E1922 − 04 (Reapproved 2015) E1922/E1922M − 22
Standard Test Method for
Translaminar Fracture Toughness of Laminated and
Pultruded Polymer Matrix Composite Materials
This standard is issued under the fixed designation E1922;E1922/E1922M; 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.
1. Scope
1.1 This test method covers the determination of translaminar fracture toughness, K , for laminated and laminated, molded, or
TL
pultruded polymer matrix composite materials of various plyfiber orientations using test results from monotonically loaded notched
specimens. If the material response is such that the K calculation is not valid, alternate reporting methods are provided.
TL
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, 5, 6).
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. used. 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.configurations in conjunction with the K calculation.
TL
1.6 Units—The values stated in either SI units or inch-pound units are to be regarded as standard. No other units of measurement
are included in this standard.separately as standard. The values stated in each system are not necessarily exact equivalents;
therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two
systems shall not be combined.
1.6.1 Within the text, the inch-pound units are shown in brackets.
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 safety, health, and healthenvironmental practices and to determine the
applicability of regulatory limitations prior to use.
This test method is under the jurisdiction of ASTM Committee D30 on Composite Materials and is the direct responsibility of Subcommittee D30.05 on Structural Test
Methods.
Current edition approved May 1, 2015May 1, 2022. Published August 2015June 2022. by Committee D30. Originally approved in 1997. 1997 by Committee E08. Last
ε1
previous edition approved in 20102015 as E1922–04(2010)E1922 – 04(2015) . DOI: 10.1520/E1922-04R15. by Committee D30. DOI: 10.1520/E1922_E1922M-22.
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
E1922/E1922M − 22
1.8 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement
D883 Terminology Relating to Plastics
D3039/D3039M Test Method for Tensile Properties of Polymer Matrix Composite Materials
D3171 Test Methods for Constituent Content of Composite Materials
D3878 Terminology for Composite Materials
D5229/D5229M Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite
Materials
D5528D5528/D5528M Test Method for Mode I Interlaminar Fracture Toughness of Unidirectional Fiber-Reinforced Polymer
Matrix Composites
D5687/D5687M Guide for Preparation of Flat Composite Panels with Processing Guidelines for Specimen Preparation
E4 Practices for Force Calibration and Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
E83 Practice for Verification and Classification of Extensometer Systems
E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or
Process
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E399 Test Method for Linear-Elastic Plane-Strain Fracture Toughness of Metallic Materials
E456 Terminology Relating to Quality and Statistics
E1823 Terminology Relating to Fatigue and Fracture Testing
3. Terminology
3.1 Definitions:
3.1.1 Terminology D3878 defines terms relating to composite materials. Terminology D883 defines terms relating to plastics.
Terminology E6, defines terms relating to mechanical testing. Terminology E1823, defines terms relating to fracture testing.
Terminology E456 and Practice E177 define terms relating to statistics. In the event of a conflict between terms, Terminology
D3878 are applicable to this test method.shall have precedence over the other standards.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 If the term represents a physical quantity, its analytical dimensions are stated immediately following the term (or letter
symbol) in fundamental dimension form, using the following ASTM standard symbology for fundamental dimensions, shown
within square brackets: [M] for mass, [L] for length, [T] for time, [θ] for thermodynamic temperature, and [nd] for non-dimensional
quantities. Use of these symbols is restricted to analytical dimensions when used with square brackets, as the symbols may have
other definitions when used without the brackets.
3.2.2 normalized notch size [nd], n—the ratio of notch length, a , to specimen width, W.
n
3.2.3 notch-mouth displacement, Vdisplacement [L], [L]—n—the Mode I (also called opening mode) component of crack or
n
notch displacement due to elastic and permanent deformation. The displacement is measured across the mouth of the notch on the
specimen edge (see Fig. 1).
3.2.4 notch length, alength [L], [L]—n—the distance from a reference plane to the front of the machined notch. The reference
n
plane depends on the specimen form, and normally is taken to be either the boundary, or a plane containing either the load line
or the centerline of a specimen or plate. The reference plane is defined prior to specimen deformation (see Fig. 2).
3.2.3 normalized notch size, a /W [nd]—the ratio of notch length, a , to specimen width, W.
n n
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
E1922/E1922M − 22
FIG. 1 Test Arrangement for Translaminar Fracture Toughness Tests
NOTE 1—All dimensions +/– 0.01 W, except as noted.
NOTE 2—AAll surfaces perpendicular and parallel as applicable within 0.01 W.
FIG. 2 Translaminar Fracture Toughness Test Specimen
3.2.5 For additional information, see Terminology D883 and Test Methods D3039/D3039M, D5229/D5229M, and D5528D5528/
D5528M.
3.3 Symbols:
a —notch length
n
B—specimen thickness
CV—coefficient of variation statistic of a sample population for a given property (in percent)
K—applied stress intensity factor
K —translaminar fracture toughness
TL
P—applied force
P —maximum applied force achieved during test
max
S —standard deviation statistic of a sample population for a given property
n-1
V —notch-mouth displacement
n
W—specimen width
x —test result for an individual specimen from the sample population for a given property
i
x¯—mean or average (estimate of mean) of a sample population for a given property
α—normalized notch size
4. Summary of Test Method
4.1 This test method involves tension testing of eccentrically loaded, single-edge-notch, ESE(T), specimens in opening mode
loading. LoadForce versus displacement across the notch at the specimen edge, V , is recorded. The loadforce corresponding to
n
a prescribed increase in normalized notch length is determined, using the load-displacementforce-displacement record. The
translaminar fracture toughness, K , is calculated from this loadforce using equations that have been established on the basis of
TL
elastic stress analysis of the modified single-edge notched specimen. When the assumptions upon which the K calculation is
TL
based are violated, results are instead reported in terms of applied force/width, geometry, and observed distributed damage.
4.2 The validity of translaminar fracture toughness, K , determined by this test method depends on maintaining a relatively
TL
E1922/E1922M − 22
contained area of damage at the notch tip. To maintain this suitable notch-tip condition, the allowed increase in notch-mouth
displacement near the maximum loadforce point of the tests is limited to a small value. Small increases in notch-mouth
displacement are more likely for relatively thick samples and for samples with a significant proportion of the near surface
reinforcing fibers aligned parallel to the direction of the notch.notch, or inherently brittle material response, or both.
4.3 For material response in which the damage is not limited to the local crack tip region, this test method results in a structural
failure response that is strongly dependent on specimen geometric details (in addition to length, width, and notch geometry) such
as fiber orientations, stacking sequence if laminated, weave architecture if woven, manufacturing process if liquid-molded or
containing discontinuous fibers, etc. In these cases, the relevant reported data is not K but rather then global observed structural
TL
response of the coupon, for example, the force-displacement history as a function of observed damage events (crack branching,
delaminations, local fiber failures, etc).
5. Significance and Use
5.1 The parameter K determined by this test method is a measure of the resistance of a polymer matrix composite laminate to
TL
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. Alternately,
for materials exhibiting distributed damage in a larger volume, observed force-displacement and discrete damage events are still
valid structural responses for certain specific engineering applications.
5.2 This test method can serve the following purposes. In research and development, (a) K data can quantitatively establish the
TL
effects of fiber and matrix variables and stacking sequence of the laminate on the translaminar fracture resistance of composite
laminates. In acceptance and qualitylaminates; and (b control specifications, ) quantified distributed damage measurements can be
used to validate progressive composite damage models. In structural design, K data can can, within the constraints of the
TL
specimen geometry and loading, be used to establish criteria for material processing and component inspection.assess composite
laminate resistance to damage growth from edge flaws and notches.
5.3 The translaminar fracture toughness, K , as well as distributed damage observations, determined by this test method may be
TL
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 9.213.2 and 9.313.3 are met. Application of K in the design
TL
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. Distributed damage observations are also
limited to the material and geometry tested, but may be more generally applied to a variety of structural analysis validation
applications.
5.4 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
beIn such circumstances, the force-displacement and discrete damage observations – not accompaniedK by any significant
TL
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.– shall be used.
5.5 The reporting section requires items that tend to influence translaminar fracture toughness and discrete damage progression
to be reported; these include the following: material, methods of material fabrication, accuracy of lay-up orientation, laminate
stacking sequence and overall thickness, specimen geometry, specimen preparation, specimen conditioning, environment of
testing, void content, volume percent reinforcement, size and method of notch preparation, specimen/fixture alignment, and speed
of testing.
6. Interferences
6.1 Material and Specimen Preparation—Poor material fabrication practices, lack of control of fiber alignment, and damage
induced by improper specimen machining are known causes of high material data scatter in composites in general. Important
aspects of specimen preparation that contribute to data scatter include thickness variation, out-of-plane curvature, surface
roughness, and failure to meet the dimensional and squareness tolerances (parallelism and perpendicularity) specified in 8.2.2.
6.2 Notch Preparation—Because of the dominating presence of the notch, results from this test method are relatively insensitive
E1922/E1922M − 22
to parameters that would be of concern in an unnotched tensile property test. However, since the notch dominates the response,
consistent preparation of the notch is important to meaningful results. Damage caused by notch preparation can affect the
calculated translaminar fracture toughness.
6.3 Geometry—Results are affected by the ratio of notch length to specimen width, as well as the ratio of notch width to specimen
width. The ratios should be maintained as specified in 8.1, unless the experiment is investigating the influence of these ratios.
6.4 Material Behavior—The inherent damage progression from the relatively blunt machined notch in this test specimen design
determines whether or not the K calculation is valid. It is the joint responsibility of the test requester and test operator to
TL
determine the validity of the calculated fracture toughness value and report the final data in an appropriate manner.
6.5 System Alignment—Errors can result if the test fixture is not centered with respect to the loading axis of the test machine.
7. Apparatus
7.1 Micrometers and Calipers—A micrometer with a 4 to 8 mm [0.16 to 0.32 in.] nominal diameter ball-interface or a flat anvil
interface shall be used to measure the specimen thickness. A ball interface is recommended for thickness measurements when at
least one surface is irregular (for example, a coarse peel ply surface which is neither smooth nor flat). A micrometer or caliper with
a flat anvil interface shall be used for measuring length, width, and other machined surface dimensions. The use of alternative
measurement devices is permitted if specified (or agreed to) by the test requestor and reported by the testing laboratory. The
accuracy of the instrument(s) shall be suitable for reading to within 1 % of the specimen dimensions. For typical specimen
geometries, an instrument with an accuracy of 60.0025 mm [60.0001 in.] is adequate for thickness measurements, while an
instrument with an accuracy of 60.025 mm [60.001 in.] is adequate for measurement of length, width, other machined surface
dimensions.
7.2 Loading—Test Fixture—Specimens shall be loaded in a testing machine that has provision for simultaneous recording of the
load applied to the specimen and the resulting notch-mouth displacement. A typical arrangement is shown in Fig. 1. Pin-loading
clevises of the type used in Test Method E399 are shall be used to apply the load force to the specimen. The accuracies of the load
measuringA typical arrangement is shown in Fig. 1and recording devices should be such that load can be determined with an
accuracy of 61 %. (For additional information see Practices .E4).
7.3 Testing Machine—The testing machine shall be in conformance with Practices E4, and shall satisfy the following
requirements:
7.3.1 Testing Machine Configuration—The testing machine shall have both an essentially stationary head and a movable head.
7.3.2 Drive Mechanism—The testing machine drive mechanism shall be capable of imparting to the movable head a controlled
velocity with respect to the stationary head. The velocity of the movable head shall be capable of being regulated as specified in
11.6.
7.3.3 Force Indicator—The testing machine force-sensing device shall be capable of indicating the total force being carried by the
test specimen. This device shall be essentially free from inertia-lag at the specified rate of testing and shall indicate the force with
an accuracy over the force range(s) of interest of within 61 % of the indicated value.
7.4 Displacement Gage—A displacement gage shall be used to measure the displacement at the notch mouth during loading. An
electronic displacement gage of the type described in Test Method E399 can provide a highly sensitive indicator of notch-mouth
displacement for this purpose. The gage is attached to the specimen using knife edges affixed to the specimen or integral knife
edges machined into the specimen. Integral knife edges may not be suitable for relatively low strength materials. Other types of
gages and attachments may be used if it can be demonstrated that they will accomplish the same result. The accuracies of the
displacement measuring and recording devices should be such that the displacement can be determined with an accuracy of 61 %.
(For additional information, see Practice E83). .)
7.5 Full-Field Strain Measurement Equipment—For quantification of distributed discrete damage events remote from the notch
tip, full field strain measurement methods such a Digital Image Correlation (DIC), high-speed photography, Moire Fringe methods,
etc. may be required. Required resolution of such methods are dependent on damage events being measured and shall be
determined by the test requester for specific materials and specimen geometries.
E1922/E1922M − 22
7.6 Data Acquisition Equipment—Equipment capable of recording force and notch mouth displacement is required. Full-field
strain measurement is optional.
8. Specimen Configuration and Preparation Sampling and Test Specimens
8.1 Sampling—It is required that enough tests be performed to obtain three valid replicate test results for each material condition.
If material variations are expected, five tests are required. For statistically significant data, the procedures outlined in Practice E122
should be consulted. The method of sampling shall be reported.
8.2 Specimen Configuration—Geometry: The required test and specimen configurations are shown in Fig. 1 and Fig. 2. The notch
length, a , shall be between 0.5 and 0.6 times the specimen width, W. The notch width shall be 0.015 W or thinner (see Fig. 2).
n
The specimen thickness, B, is the full thickness of the composite material to be tested. A thickness as small as 2 mm has been found
to work well. However, too small a thickness can cause out-of-plane buckling, which invalidates the test. The specimen width is
selected by the user. A value of W between 25 and 50 mm has been found to work well. Other specimen dimensions are based
on specimen width.
8.2.1 Stacking Sequence—The specimen shall have multidirectional fiber orientations (fibers oriented in a minimum of two
directions), with the 0° fiber orientation aligned with the lengthwise (long) dimension. A thickness as small as 2 mm has been found
to work well. However, too small a thickness can cause out-of-plane buckling, which invalidates the test. The 0° fiber orientation
of the specimen before testing shall be aligned to within 2° of the intended loadi
...