ASTM D5587-96

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 5587 – 96
Standard Test Method for
Tearing Strength of Fabrics by Trapezoid Procedure
This standard is issued under the fixed designation D 5587; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 629 Test Methods for Quantitative Analysis of Textiles
D 1776 Practice for Conditioning Textiles for Testing
1.1 This test method covers the measurement of the tearing
D 2904 Practice for Interlaboratory Testing of a Textile Test
strength of textile fabrics by the trapezoid procedure using a
Method That Produces Normally Distributed Data
recording constant-rate-of-extension-type (CRE) tensile testing
D 2906 Practice for Statements on Precision and Bias for
machine.
Textiles
1.1.1 The CRE-type tensile testing machine has become the
D 4848 Terminology of Force, Deformation and Related
preferred test apparatus for determining trapezoid tearing
Properties of Textiles
strength. It is recognized that some constant-rate-of-traverse-
2.2 ASTM Adjuncts:
type (CRT) tensile testing machines continue to be used.
TEX-PAC
Consequently, these test instruments may be used when agreed
upon between the purchaser and the supplier. The conditions
3. Terminology
for use of the CRT-type tensile tester are included in Appendix
3.1 Definitions—For definitions of other textile terms used
X1.
in this test method, refer to Terminology D 123. For definitions
1.2 This test method applies to most fabrics including
of other terms related to force and deformation in textiles, refer
woven fabrics, air bag fabrics, blankets, napped fabrics, knitted
to Terminology D 4848.
fabrics, layered fabrics, and pile fabrics. The fabrics may be
3.2 Definitions of Terms Specific to This Standard:
untreated, heavily sized, coated, resin-treated, or otherwise
3.2.1 cross-machine direction, CD, n—the direction in the
treated. Instructions are provided for testing specimens with or
plane of the fabric perpendicular to the direction of manufac-
without wetting.
ture.
1.3 Tearing strength, as measured in this test method,
3.2.1.1 Discussion—This term is used to refer to the direc-
requires that the tear be initiated before testing. The reported
tion analogous to coursewise or filling direction in knitted or
value obtained is not directly related to the force required to
woven fabrics, respectively.
initiate or start a tear.
3.2.2 fabric, in textiles, n—a planar structure consisting of
1.4 Two calculations for trapezoid tearing strength are
yarns or fibers.
provided: the single-peak force and the average of five highest
3.2.3 machine direction, MD, n—the direction in the plane
peak forces.
of the fabric parallel to the direction of manufacture.
1.5 The values stated in SI units are to be regarded as the
3.2.3.1 Discussion—This term is used to refer to the direc-
standard. The values stated in inch-pound units may be
tion analogous to walewise or warp direction in knitted or
approximate.
woven fabrics, respectively.
1.6 This standard does not purport to address all of the
3.2.4 peak force, in tear testing of fabrics, n—the maximum
safety concerns, if any, associated with its use. It is the
force required to break one or more yarn components in a
responsibility of the user of this standard to establish appro-
woven or knitted fabric specimen, or break the fiber, the fiber
priate safety and health practices and determine the applica-
bonds, or fiber interlocks in other manufactured fabric forms.
bility of regulatory limitations prior to use.
3.2.4.1 Discussion—The peak force may consist of a single
2. Referenced Documents peak or a series of peaks depending upon the nature of the
fabric. Typically for woven fabrics, if a small decrease in force
2.1 ASTM Standards:
occurs at a time when the force is increasing, it is not
D 76 Specification for Tensile Testing Machines for Tex-
considered to peak unless the indicated force exceeds the force
tiles
2 required to break a yarn. Lower shifts corresponding to yarn
D 123 Terminology Relating to Textiles
movement do not qualify as peaks since no yarns are broken.
This test method is under the jurisdiction of ASTM Committee D-13 on Textiles
and is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods, Annual Book of ASTM Standards, Vol 07.02.
Specific. The PC programs on floppy disks for analyzing Committee D-13 interlabora-
Current edition approved Feb. 10, 1996. Published April 1996. tory data are available from ASTM. For a 3 ⁄2-in. disk, request PCN:12-429040-18,
Annual Book of ASTM Standards, Vol 07.01. and for a 5 ⁄4-in. disk, request PCN:12-429041-18.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 5587
3.2.5 tearing force, in fabric, n—the force required to plier should conduct comparative tests to determine if there is
propagate a tear initiated under specified conditions. a statistical bias between their laboratories. Competent statis-
3.2.5.1 Discussion—The trapezoid tearing force may be tical assistance is recommended for the investigation of bias.
calculated from a single peak or a multiple-peak force- As a minimum, the two parties should take a group of test
extension curve. specimens that are as homogeneous as possible and that are
3.2.6 tearing strength, in fabrics, n—the capacity of a fabric from a lot of material of the type in question. Test specimens
to withstand the tearing force required to propagate a tear after then should be randomly assigned in equal numbers to each
its initiation. laboratory for testing. The average results from the two
laboratories should be compared using the appropriate statis-
4. Summary of Test Method
tical analysis and an acceptable probability level chosen by the
two parties before testing is begun. If a bias is found, either its
4.1 An outline of an isosceles trapezoid is marked on a
cause must be found and corrected, or the purchaser and the
rectangular specimen (see Fig. 1). The specimen is slit at the
supplier must agree to interpret future test results with consid-
center of the smallest base of the trapezoid to start the tear. The
eration to the known bias.
nonparallel sides of the marked trapezoid are clamped in
5.2 The trapezoid tear produces tension along a reasonably
parallel jaws of a tensile testing machine. The separation of the
defined course such that the tear propagates across the width of
jaws is increased continuously to apply a force to propagate the
the specimen. It is useful for estimating the relative tear
tear across the specimen. At the same time, the force developed
resistance of different fabrics or different directions in the same
is recorded. The force to continue the tear is calculated from
fabric.
autographic chart recorders or microprocessor data collection
5.3 Depending on the nature of the specimen, the data
systems.
recording devices will show the tearing force in the form of a
5. Significance and Use peak or peaks. The highest peaks appear to reflect the strength
of the yarn components, individually or in combination, needed
5.1 This test method is considered satisfactory for accep-
to stop a tear in fabrics of the same construction. The valleys
tance testing of commercial shipments since current estimates
recorded between the peaks have no specific significance. The
of between-laboratory precision are acceptable, and this test
minimum tearing force, however, is indicated to be above the
method is used extensively in the trade for acceptance testing.
lowest valleys.
5.1.1 In case of a dispute arising from differences in
5.4 Most textile fabrics can be tested by this test method.
reported test results when using this test method for acceptance
Some modification of clamping techniques may be necessary
testing of commercial shipments, the purchaser and the sup-
for a given fabric, depending upon its structure. Strong fabrics
or fabrics made from glass fibers require special adaptation to
prevent them from slipping in the clamps or being damaged as
a result of being gripped in the clamps.
5.5 The CRE-type is the preferred tensile testing machine.
This test method allows the use of the CRT-type tensile
machine when agreed upon between the purchaser and the
supplier. There may be no overall correlation, however, be-
tween the results obtained with the CRT-type machine and the
CRE-type machine. Consequently, these two tensile testers
cannot be used interchangeably unless the degree of quantita-
tive correlation has been established between the purchaser and
the supplier. In any event, the CRE-type machine shall prevail.
(a)
6. Apparatus
6.1 Tensile Testing Machine, of the CRE-type conforming to
the requirements of Specification D 76 with autographic re-
corder, or automatic microprocessor data gathering system.
6.2 Clamps, having all gripping surfaces parallel, flat, and
capable of preventing slipping of the specimen during a test,
and measuring at least 50 by 75 mm (at least 2 by 3 in.), with
the longer dimension perpendicular to the direction of appli-
cation of the force.
6.2.1 The use of hydraulic pneumatic clamping systems
with a minimum of 50 by 75-mm (2 by 3-in.) serrated or rubber
jaw faces having a clamping force at the grip faces of 13 to 14
kN (2900 to 3111 lbf) is recommended. Manual clamping is
permitted providing no slippage of the specimen is observed.
(b)
6.2.2 For some fabrics, to prevent slippage when using jaw
FIG. 1 Templates for Cutting and Marking Trapezoid Test
Specimens faces other than serrated, such as rubber-faced jaws, the jaw
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 5587
faces may be covered with a No. 80 to 120 medium-grit emery the laboratory sample, and no nearer the edge than one tenth its
cloth. Secure the emery cloth to the jaw faces with pressure- width. Ensure specimens are free of folds, creases, or wrinkles.
sensitive tape. Avoid getting oil, water, grease, and so forth, on the specimens
6.3 Cutting Die or Template, having essentially the shape when handling.
and dimensions shown in Fig. 1a. 7.3.2.3 Use the cutting die or template described in 6.3 and
6.4 Trapezoid-Shaped Template, having dimensions as shown in Fig. 1. Mark each specimen with an isosceles
shown in Fig. 1b. trapezoid template (see Figs. 1 and 2). Make a preliminary cut
15 mm (0.625 in.) long at the center of the 25-mm (1-in.) edge,
7. Sampling and Test Specimens
as shown in Figs. 1 and 2.
7.1 Lot Sample—As a lot sample for acceptance testing,
8. Preparation of Test Apparatus and Calibration
randomly select the number of rolls or pieces of fabric directed
8.1 Set the distance between the clamps at the start of the
in an applicable material specification or other agreement
test at 25 6 1mm(1 6 0.05 in.).
between the purchaser and the supplier. Consider the rolls or
8.2 Select the full-scale force range of the testing machine
pieces of fabric to be the primary sampling units. In the
such that the maximum force occurs between 15 and 85 % of
absence of such an agreement, take the number of fabric rolls
full-scale force.
specified in Table 1.
8.3 Set the testing speed to 300 6 10 mm (12 6 0.5
NOTE 1—An adequate specification or other agreement between the
in./min).
purchaser and the supplier requires taking into account the variability
8.4 Verify calibration of the tensile testing machine as
between rolls or pieces of fabric and between specimens from a swatch
specified in the manufacturer’s instructions and Specification
from a roll or piece of fabric to provide a sampling plan with a meaningful
D 76.
producer’s risk, consumer’s risk, acceptable quality level, and limiting
quality level.
8.5 When using microprocessor automatic data gathering
systems, set the appropriate parameters as specified in the
7.2 Laboratory Sample—For acceptance testing, take a
manufacturer’s instructions.
swatch extending the width of the fabric and approximately 1
m (1 yd) along the machine direction from each roll or piece in
9. Conditioning
the lot sample. For rolls of fabric, take a sample that will
9.1 Condition 1, for Standard Testing:
exclude fabric from the outer wrap of the roll or the inner wrap
9.1.1 Precondition the specimens by bringing them to ap-
around the core of the roll of fabric.
proximate moisture equilibrium in the standard atmosphere for
7.3 Test Specimens—From each laboratory sampling unit,
preconditioning textiles as specified in Practice D 1776, unless
take five specimens from the machine direction and five
otherwise specified in a material specification or contract order.
specimens from the cross-machine direction, for each test
9.1.2 After preconditioning, bring the test specimens to
condition described in 9.1 and 9.2, as applicable to a material
moisture equilibrium for testing in the standard atmosphere for
specification or contract order.
testing textiles as specified in Practice D 1776 or, if applicable,
7.3.1 Direction of Test—Consider the long direction as the
in the specified atmosphere in which the testing is to be
direction of test.
performed, unless otherwise directed in a material specification
7.3.2 Cutting Test Specimens—Take the specimens to be
or contract order.
used for the measurement of machine direction with the longer
9.2 Condition 2, for Wet Specimen Testing:
dimension parallel to the machine direction. Take the speci-
9.2.1 When desizing treatments are specified prior to wet
mens to be used for the measurement of the cross-machine
testing, use desizing treatments that will not affect the normal
direction with the longer dimension parallel to the cross-
physical property of the fabric as specified in Test Method
machine direction. When specimens are to be tested wet, take
D 629.
the specimens from areas adjacent to the dry test specimens.
9.2.2 Submerge the specimens in a container of distilled or
Label to maintain specimen identity.
deionized water at ambient temperature until thoroughly
7.3.2.1 In cutting the woven fabric specimens, take care to
soaked (see section 8.2.1.1).
align the yarns running in the short direction parallel with the
9.2.2.1 The time of immersion must be sufficient to wet out
die such that when the slit is cut, the subsequent tear will take
place between these yarns and not across them. This precaution
is most importa
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