ASTM D5587-96(2003)
(Test Method)Standard Test Method for Tearing Strength of Fabrics by Trapezoid Procedure
Standard Test Method for Tearing Strength of Fabrics by Trapezoid Procedure
SCOPE
1.1 This test method covers the measurement of the tearing strength of textile fabrics by the trapezoid procedure using a recording constant-rate-of-extension-type (CRE) tensile testing machine.
1.1.1 The CRE-type tensile testing machine has become the preferred test apparatus for determining trapezoid tearing strength. It is recognized that some constant-rate-of-traverse-type (CRT) tensile testing machines continue to be used. Consequently, these test instruments may be used when agreed upon between the purchaser and the supplier. The conditions for use of the CRT-type tensile tester are included in Appendix X1.
1.2 This test method applies to most fabrics including woven fabrics, air bag fabrics, blankets, napped fabrics, knitted fabrics, layered fabrics, and pile fabrics. The fabrics may be untreated, heavily sized, coated, resin-treated, or otherwise treated. Instructions are provided for testing specimens with or without wetting.
1.3 Tearing strength, as measured in this test method, requires that the tear be initiated before testing. The reported value obtained is not directly related to the force required to initiate or start a tear.
1.4 Two calculations for trapezoid tearing strength are provided: the single-peak force and the average of five highest peak forces.
1.5 The values stated in SI units are to be regarded as the standard. The values stated in inch-pound units may be approximate.
1.6 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.
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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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Designation: D 5587 – 96 (Reapproved 2003)
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 76 Specification for Tensile Testing Machines for Tex-
tiles
1.1 This test method covers the measurement of the tearing
D 123 Terminology Relating to Textiles
strength of textile fabrics by the trapezoid procedure using a
D 629 Test Methods for Quantitative Analysis of Textiles
recording constant-rate-of-extension-type (CRE) tensile testing
D 1776 Practice for Conditioning Textiles for Testing
machine.
D 2904 Practice for Interlaboratory Testing of a Textile Test
1.1.1 The CRE-type tensile testing machine has become the
Method That Produces Normally Distributed Data
preferred test apparatus for determining trapezoid tearing
D 2906 Practice for Statements on Precision and Bias for
strength. It is recognized that some constant-rate-of-traverse-
Textiles
type (CRT) tensile testing machines continue to be used.
D 4848 Terminology of Force, Deformation and Related
Consequently, these test instruments may be used when agreed
Properties of Textiles
upon between the purchaser and the supplier. The conditions
2.2 ASTM Adjuncts:
for use of the CRT-type tensile tester are included in Appendix
TEX-PAC
X1.
1.2 This test method applies to most fabrics including
3. Terminology
woven fabrics, air bag fabrics, blankets, napped fabrics, knitted
3.1 Definitions—For definitions of other textile terms used
fabrics, layered fabrics, and pile fabrics. The fabrics may be
in this test method, refer to Terminology D 123. For definitions
untreated, heavily sized, coated, resin-treated, or otherwise
of other terms related to force and deformation in textiles, refer
treated. Instructions are provided for testing specimens with or
to Terminology D 4848.
without wetting.
3.2 Definitions of Terms Specific to This Standard:
1.3 Tearing strength, as measured in this test method,
3.2.1 cross-machine direction, CD, n—the direction in the
requires that the tear be initiated before testing. The reported
plane of the fabric perpendicular to the direction of manufac-
value obtained is not directly related to the force required to
ture.
initiate or start a tear.
3.2.1.1 Discussion—This term is used to refer to the direc-
1.4 Two calculations for trapezoid tearing strength are
tion analogous to coursewise or filling direction in knitted or
provided: the single-peak force and the average of five highest
woven fabrics, respectively.
peak forces.
3.2.2 fabric, in textiles, n—a planar structure consisting of
1.5 The values stated in SI units are to be regarded as the
yarns or fibers.
standard. The values stated in inch-pound units may be
3.2.3 machine direction, MD, n—the direction in the plane
approximate.
of the fabric parallel to the direction of manufacture.
1.6 This standard does not purport to address all of the
3.2.3.1 Discussion—This term is used to refer to the direc-
safety concerns, if any, associated with its use. It is the
tion analogous to walewise or warp direction in knitted or
responsibility of the user of this standard to establish appro-
woven fabrics, respectively.
priate safety and health practices and determine the applica-
3.2.4 peak force, in tear testing of fabrics, n—the maximum
bility of regulatory limitations prior to use.
force required to break one or more yarn components in a
2. Referenced Documents woven or knitted fabric specimen, or break the fiber, the fiber
bonds, or fiber interlocks in other manufactured fabric forms.
2.1 ASTM Standards:
Annual Book of ASTM Standards, Vol 07.01.
1 3
This test method is under the jurisdiction of ASTM Committee D13 on Textiles Annual Book of ASTM Standards, Vol 07.02.
and is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods, The PC programs on floppy disks for analyzing Committee D-13 interlabora-
Specific. tory data are available from ASTM. For a 3 ⁄2-in. disk, request PCN:12-429040-18,
Current edition approved Feb. 10, 1996. Published April 1996. and for a 5 ⁄4-in. disk, request PCN:12-429041-18.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, 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 – 96 (2003)
3.2.4.1 Discussion—The peak force may consist of a single 5. Significance and Use
peak or a series of peaks depending upon the nature of the
5.1 This test method is considered satisfactory for accep-
fabric. Typically for woven fabrics, if a small decrease in force
tance testing of commercial shipments since current estimates
occurs at a time when the force is increasing, it is not
of between-laboratory precision are acceptable, and this test
considered to peak unless the indicated force exceeds the force
method is used extensively in the trade for acceptance testing.
required to break a yarn. Lower shifts corresponding to yarn
5.1.1 In case of a dispute arising from differences in
movement do not qualify as peaks since no yarns are broken.
reported test results when using this test method for acceptance
3.2.5 tearing force, in fabric, n—the force required to
testing of commercial shipments, the purchaser and the sup-
propagate a tear initiated under specified conditions.
plier should conduct comparative tests to determine if there is
3.2.5.1 Discussion—The trapezoid tearing force may be a statistical bias between their laboratories. Competent statis-
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
4.1 An outline of an isosceles trapezoid is marked on a
two parties before testing is begun. If a bias is found, either its
rectangular specimen (see Fig. 1). The specimen is slit at the
cause must be found and corrected, or the purchaser and the
center of the smallest base of the trapezoid to start the tear. The
supplier must agree to interpret future test results with consid-
nonparallel sides of the marked trapezoid are clamped in eration to the known bias.
parallel jaws of a tensile testing machine. The separation of the
5.2 The trapezoid tear produces tension along a reasonably
jaws is increased continuously to apply a force to propagate the
defined course such that the tear propagates across the width of
tear across the specimen. At the same time, the force developed
the specimen. It is useful for estimating the relative tear
is recorded. The force to continue the tear is calculated from
resistance of different fabrics or different directions in the same
autographic chart recorders or microprocessor data collection
fabric.
systems.
5.3 Depending on the nature of the specimen, the data
recording devices will show the tearing force in the form of a
peak or peaks. The highest peaks appear to reflect the strength
of the yarn components, individually or in combination, needed
to stop a tear in fabrics of the same construction. The valleys
recorded between the peaks have no specific significance. The
minimum tearing force, however, is indicated to be above the
lowest valleys.
5.4 Most textile fabrics can be tested by this test method.
Some modification of clamping techniques may be necessary
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.
(a)
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.
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.
(b)
6.2 Clamps, having all gripping surfaces parallel, flat, and
FIG. 1 Templates for Cutting and Marking Trapezoid Test
Specimens capable of preventing slipping of the specimen during a test,
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 – 96 (2003)
and measuring at least 50 by 75 mm (at least 2 by 3 in.), with machine direction. When specimens are to be tested wet, take
the longer dimension perpendicular to the direction of appli- the specimens from areas adjacent to the dry test specimens.
cation of the force. Label to maintain specimen identity.
6.2.1 The use of hydraulic pneumatic clamping systems 7.3.2.1 In cutting the woven fabric specimens, take care to
with a minimum of 50 by 75-mm (2 by 3-in.) serrated or rubber align the yarns running in the short direction parallel with the
jaw faces having a clamping force at the grip faces of 13 to 14 die such that when the slit is cut, the subsequent tear will take
kN (2900 to 3111 lbf) is recommended. Manual clamping is place between these yarns and not across them. This precaution
permitted providing no slippage of the specimen is observed. is most important when testing bowed fabrics.
6.2.2 For some fabrics, to prevent slippage when using jaw 7.3.2.2 Cut specimens representing a broad distribution
faces other than serrated, such as rubber-faced jaws, the jaw across the width and length, preferably along the diagonal of
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
in an applicable material specification or other agreement
8.1 Set the distance between the clamps at the start of the
between the purchaser and the supplier. Consider the rolls or
test at 25 6 1mm(1 6 0.05 in.).
pieces of fabric to be the primary sampling units. In the
8.2 Select the full-scale force range of the testing machine
absence of such an agreement, take the number of fabric rolls
such that the maximum force occurs between 15 and 85 % of
specified in Table 1.
full-scale force.
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
between rolls or pieces of fabric and between specimens from a swatch
8.4 Verify calibration of the tensile testing machine as
from a roll or piece of fabric to provide a sampling plan with a meaningful
specified in the manufacturer’s instructions and Specification
producer’s risk, consumer’s risk, acceptable quality level, and limiting
D 76.
quality level.
8.5 When using microprocessor automatic data gathering
7.2 Laboratory Sample—For acceptance testing, take a
systems, set the appropriate parameters as specified in the
swatch extending the width of the fabric and approximately 1
manufacturer’s instructions.
m (1 yd) along the machine direction from each roll or piece in
the lot sample. For rolls of fabric, take a sample that will
9. Conditioning
exclude fabric from the outer wrap of the roll or the inner wrap
9.1 Condition 1, for Standard Testing:
around the core of the roll of fabric.
9.1.1 Precondition the specimens by bringing them to ap-
7.3 Test Specimens—From each laboratory sampling unit,
proximate moisture equilibrium in the standard atmosphere for
take five specimens from the machine direction and five
preconditioning textiles as specified in Practice D 1776, unless
specimens from the cross-machine direction, for each test
otherwise specified in a material specification or contract order.
condition described in 9.1 and 9.2, as applicable to a material
9.1.2 After preconditioning, bring the test specimens to
specification or contract order.
moisture equilibrium for testing in the standard atmosphere for
7.3.1 Direction of Test—Consider the long direction as the
testing textiles as specified in Practice D 1776 or, if applicable,
direction of test.
7.3.2 Cutting Test Specimens—Take the specimens to be
used for the measurement of machine direction with the longer
dimension parallel to the machine direction. Take the speci-
mens to be used for the measurement of the cross-machine
direction with the longer dimension parallel to the cross-
TABLE 1 Number of Rolls or Pieces of Fabric in the Lot Sample
Number of Rolls or Pieces
Number of Rolls or Pieces in Lot Sample
in Lot, Inclusive
1to3 all
4to24 4
25 to 50 5
over 50 10 % to a maximum of 10 rolls or pieces
FIG. 2 Diagram of Marked Trapezoid Specimen
NOTICE: This standard has either b
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