Designation: D 1775 - 94

Standard Test Method for

Tension and Elongation of Wide Elastic Fabrics (Constant-
Rate-of-Load Type Tensile Testing Machine)1

This standard is issued under the fixed designation D 1775; 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
(o) indicates an editorial change since :he last revision or reapproval.

1. Scope
1.1 This test method covers the measurement of tension and elongation characteristics of wide
elastic fabrics made from natural or man-made elastomers, either alone or in combination with
other textile yarns, when tested with a constant-rate-of-loading (CRL) type tensile testing
machine.

NOTE l-For determination of similar testing using the constant rate of extension (CRL) type
tensile testing machine, refer to Test Method D 4964.1.1.1 This test method is not applicable to
narrow elastic fabrics.

1.2 The use of this test method requires the selection of, or mutual agreement upon, tension(s)
and elongation(s) at which the test results will be determined.
1.3 In testing laundered elastic fabrics, the laundering procedures require mutual agreement on
the selection of temperature and number of washing cycles and drying cycles to be used.
1.4 The values stated in SI units or inch-pound units are to be regarded separately as standard.
The values stated in each system may not be exact equivalents; therefore each system must be
used independently of the other, without combining values in any way.
1.5 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.

2. Referenced Documents
2.1 ASTM Standards:
D 76 Specification for Tensile Testing Machines for Textiles-
D 123 Terminology Relating to Textiles-
D 1776 Practice for Conditioning Textiles for Testing-
D4964 Test Method for Tension and Elongation of Elastic
Fabrics (Constant-Rate-of-Extension Type Tensile
Testing Machine)³
2.2 AATCC Method:
124 Appearance of Durable Press Fabrics after Repeated Home Laundering"
3. Terminology
3.1 Definitions:
3.1.1 constant-rate-of-extension tensile testing machine (CRE), n-a testing machine in which the
rate of increase of specimen length is uniform with time.
3.1.2 constant-rate-of-load tensile testing machine (CRL), n-a testing machine in which the rate
of increase of the load being applied to the specimen is uniform with time after the first 3 s.
3.1.3 ejJective carriage mass, n-in CRL-type tensile testing machine, the force actually applied
to a specimen by the mass of the carriage.
3.1.4 elastic fabric, n-a textile fabric made from an elastomer either alone or in combination with
other textile materials.
3.1.5 elongation, n-the ratio of the extension of a material to the length of the material prior to
stretching, expressed as a percent.
3.1.6 extension, n-the change in length of a material due to stretching.
3.1. 7 extension-recovery chart, n-in elastic materials testing, a continuously plotted graph of
tension versus extension resulting from an extension-recovery cycle.
3.1.8 force, n-a physical influence exerted by one body on another which produces acceleration
of bodies that are free to move and deformation of bodies that are not free to move.
3.1.9 loop tension, n-in elastic material testing, the total tension at any specified extension that
is exerted on a specimen in a loop formation.
3.1.10 narrow elastic fabric, n-an elastic fabric that is less than 150 mm or 6 in. wide.
3.1.11 tension, n-a uniaxial force tending to cause the stretching of a material.
3.1.12 tension-recovery chart, n-in tension testing, a continuously plotted graph of tension
versus extension resulting from a tension-recovery cycle.
3.1.13 tension test, n-in textiles, a test designed to measure the tautness in a textile strand or
fabric.
3.1.1.4 wide elastic fabric, n-an elastic fabric that is at least 150 mm or 6 in. wide.
3.1.1.5 For definitions of other textile terms used in this test method, refer to Terminology D
123.

4. Summary of Test Method

4.1 Tension at Specified Elongation(s)-A conditioned loop specimen is mounted in a CRL-type
tensile testing machine. The specimen is then subjected to specified tension using a specified
effective carriage mass and returned to zero tension. The cycle is repeated two more times to
give a total of three cycles. During the test, extension-recovery curves maybe plotted by an
automatic recorder for all or only the third cycle. The tension at specified elongation(s) is
calculated from the graph of the third cycle.
4.2 Elongation at Specified Tension-A conditioned loop specimen is mounted in a CRL- Type
tensile testing machine. The specimen is subjected to a specified tension and cycled as in 4.1.
During the test, tension-recovery curves may be plotted by an automatic recorder for all or only
the third cycle. The elongation at a specified tension is calculated from the graph of the third
cycle.
5. Significance and Use
5.1 This method for testing tension and elongation of elastic fabrics is considered satisfactory
for acceptance testing of commercial shipments of wide elastic fabrics because the test method
is used in the trade for acceptance testing.
5.1.1 In the case of a dispute arising from differences in reported test results when using this
test method for acceptance testing of commercial shipments, the parties should conduct
comparative tests to determine if there is a statistical bias between their laboratories.
Competent statistical assistance is recommended for the investigation of bias. As a minimum,
the two parties should take a group of test specimens that are as homogeneous as possible and
that are from a lot of material of the type in question. The test specimens should then be
randomly assigned in equal numbers to each laboratory for testing. The average results from
the two laboratories should be compared using Student's t-test for unpaired data and an
acceptable probability leveI chosen by the two parties before the testing is begun. If bias is
found, either its cause must be found and corrected or the purchaser and the supplier must
agree to interpret future test results in the light of the known bias.
5.2 This test method specifies CRL- Type tensile testing machines of the inclined-plane type
which was the type used in the interlaboratory tests performed to determine the reproducibility
and reliability of these procedures.
5.3 Users of this test method are cautioned that tension test data obtained using this test
method are not comparable to tension test data obtained using Test Method D 4964 because of
the differences in testing machines. Test Method D 4964 uses a CRE- Type tensile testing
machine.
5.4 The tension and extension relationship of an elastic fabrics an important criterion for judging
the suitability of the fabric for various end uses, such as: foundation garments, brassieres, and
swimsuits.
5.5 The test for measuring tension at specified elongation(s) is used to determine the tension of
an elastic fabric when subjected to a specified elongation which is less than lhe elongation
required to rupture the fabric The test prescribes points of measurement on the extending
(outgoing) cycle only.
5.6 The test for measuring elongation at specified tension(s)is used to determine the elongation
of an elastic fabric FIG. 1 Loop Specimen in Place on Pins when subjected to a specified
tension which is less than the tension required to rupture the fabric The test prescribes
points of measurement on the loading (outgoing) cycle only.
5.7 The tension and extension recorded for any fabric will vary appreciably with differences in
the effective mass of the testing machine because of the differences in the rate of loadings. As
a consequence, the effective carriage mass must be specified before testing and reported with
the test results.
6. Apparatus
6.1 Tensile Testing Machine, CRL-Type,5 equipped with recording pen and chart recording
device and conforming to Specification D 76.
6.2 Pins or Rods, for' holding loop specimen during testing. See Fig. 1.
6.3 Single-Needle Sewing Machine.
6.4 Rule, or other measuring device, at least 300 mm, or
12 in., long and graduated in l-mm, or 0.02-in." units.
6.5 Stop watch, to read in seconds.
7. Sampling
7.1 Lot Sample-As a lot sample for acceptance testing, take at random the number of roIls of
fabric as directed in an applicable material specification or other agreement between the
purchaser and the supplier. Consider roIls of fabric to be the primary sampling units.

NOTE 2-An adequate specification or other agreement between the purchaser and the supplier
requires taking into account the variability between rolls of fabric, and the variability between
specimens from a swatch from a roll of fabric, to provide a sampling plan with a meaningful
producer's risk, consumer's risk, acceptable quality levei, and limiting quality leveI.
7.2 Laboratory Sample-As a laboratory sample for acceptance testing, take a fuIl width swatch
2-m, or 2-yd, long from the end of each roIl of fabric in the lot sample, after first discarding a
minimum of l-m, or l-yd, of fabric from the very outside of the roIl.
7.3 Test Specimens-Take test specimens as foIlows:
7.3.1 If the purchaser and the supplier agree to test the fabric in only one direction, cut five
specimens from each swatch in the laboratory sample with the long dimension of the specimens
paraIlel to the direction of test

7.3.2 If the purchaser and the supplier agree to test the fabric in both directions, from each full-
width swatch in the laboratory sample, cut five specimens paralIel to the long dimension and
five specimens perpendicular to the long dimension. Specimens should be spaced along a
diagonal to allow for representation in each specimen of different warp and filling areas, or wale
and course areas.
7.3.3 Take no specimens nearer than one-tenth of the fabric width from the selvage. Fabrics
less than 14 in. wide should not be used for filIing tests by this method.
8. Conditioning
8.1 Before making any tests for tension or stretch, bring the samples to moisture equilibrium for
testing in the standard atmosphere for testing textiles which is 21 ± I''C (70 ± 2°F) temperature
and 65 ± 2 % relative humidity. Allow the samples to relax, free from tension, for a minimum of
16 hours. After exposure for this time, it may be assumed that moisture equilibrium has been
reached. See Practice D 1776 for standard conditions for testing textile materials.
9. Preparation of Test Specimens
9.1 Cutting Specimens:
9.1.1 Cut specimens that will not be raveled 350 mm, or 14 in., long and 75 ± 1.2 mm, or 3 ±
0.05 in., wide.
9.1.2 Cut specimens that will be raveled 98 mm, or 3.5 in., wide by 350 mm, or 14 in., long, then
ravel yarns alternately from each of the two long sides to a width as near 75 mm, or 3 in., as
possible.
9.1.3 For warp tension and elongation measurements, the long direction of the specimens
should be paralIel to the warp. For filling tension and elongation measurement, the long
direction should be parallel to the filling (perpendicular to the warp).
9.2 Preparation of Loop Specimens-Draw two gage marks on the specimen which are: (1) 250 ±
2 mm, or 10.0 ± 0.05 in., apart, (2) approximately the same distance from the specimen ends,
(3) paralIel to one another, and (4) perpendicular to the long direction of the test specimen.
Form a loop by folding the specimen; then aligning and sewing a seam along the two gage
marks. Use a single-needle stitch, sewing two rows of stitching and making certain that the
beginning' and ending stitches do not come loose.
10. Preparation and Verification of Apparatus
10.1 Preparation of Apparatus:
10.1.1 Set-up the CRL-type tensile testing machine according to the manufacturer's instructions
and using:
10.1.1.1 A standard mass or effective carriage mass of 13.6 kg, or 30 lb, except as otherwise
agreed upon,
10.1.1.2 Machine cycle time of 40 ± 2 s, and
10.1.1.3 Pins or rods for holding specimens.
10.2 Verification of Loop Test Length:
10.2.1 Cut a strip of flexible paper that measures 275 ± 2 mm by 10 ± 2 mm, or 11.0 ± 0.05 in.
by 0.5 ± 0.05 in.
10.2.2 From one end of paper strip, measure a distance of 250 ± 2 mm, or 10.0 ± 0.05 in., and
draw a line perpendicular to the long axis.
10.2.3 Place a strip of double-faced tape across the strip, and on the short end, coincident with
the line.
10.2.4 Curl the untaped end of the strip to form a loop, aligning the end with the 250 mm, or 10
in., line. Press down on the strip, fastening it to the double-faced tape.
10.2.5 Place the paper loop around the testing machine pins, or rods, with the taped joint
between the pins or rods. See Fig. 1.
10.2.6 Adjust the spacing between the pins, or rods, until the loop is just snug. Then, remove
the paper loop.
11. Procedure
11.1 Test all specimens in standard atmosphere for testing textiles which is 21 ± 1°C (70 ± 2°F)
and 65 ± 2 % relative humidity.
11.2 Place a chart on the platen squarely against the platen pins. Insert a pen in the holder and
adjust the pen or platen, or both, for the pen to register zero tension and zero extension. Before
starting the test, traverse the carriage in a horizontal plane to ensure that the pen registers on
the zero-tension line of the chart.
11.3 Mount the specimen with the seam between the pins, or rods. See Fig. 1.
11.4 Raise the pen from contact with the chart and apply the force of the carriage to the full
inclination of the plane of the testing machine and then return the carriage to the horizontal
position. Repeat the cycle, lower the pen at the end of this second cycle, and repeat for a third
cycle. Record the entire third cycle before stopping the machine.
11.5 For Loop Tension Measurement-Read the tension from the third-cycle tension-extension
curve at 20, 40 and 60 % elongation (preferred), or as otherwise agreed upon elongation.
11.5.1 Use tension values that are no less than 10 % of the effective carriage mass. Thus,
tension values less than 1.36-kg, or 3 lb, would not be read in tests using a 13.6-kg, or 30-lb,
effective carriage mass.
11.6 For Elongation at Specified Tension Measurement-Read the extension at the maximum, or
otherwise specified tension from the third cycle of the tension-extension curve.
11.7 Test the remaining specimens.
12. Calculation
12.1 Tension at Specified Elongations:
12.1.1 Determine the chart equivalent of the tension for 20 %, 40 %, and 60 % elongations, or
for the agreed upon percent elongation(s).
12.1.2 Read and record the tensions at the elongations specified in 12.1.1.
12.1.3 Calculate the loop tension for a 25-mm, or l-in, wide specimen at each specified
elongation, to the nearest 0.02 N/mm, (0.1 lbf/in.), using Eq 1:
L=F/W (11
where:
L = loop tension, N/mm (lbf/in.),
F = observed loop tension from 12.1.2, kg (lbf), and
W = specimen width, mm (in.).
NOTE 3- To convert from pounds-force (lbf) to newtons (N), multiply by 4.447.
12.2 Elongation at Specified Tension-Calculate the percent elongation at the specified tension
(9.07 N (20 lbf)), or other agreed upon tension, to the nearest percent.

12.3 Calculate the average tension (or elongation) for each specified elongation (or tension), or
both, if requested.
12.4 Calculate the standard deviation, or the coefficient of variation, or both, for each property if
requested.
13.Report
13.1 State that the specimens were tested as directed in Test Method D 1775. Describe the
material(s) or product(s) sampled and the method of sampling used.
13.2 Report the following information:
13.2.1 The loop tension at 20 %, 40 %, and 60 % elongation, or other specified percent
elongation, if requested,
13.2.2 The percent elongation at the tension used, if calculated,
13.2.3 The standard deviation, or coefficient of variation,
orboth, if calculated,
13.2.4 The maximum tension used,
13.2.5 The specimen width,
13.2.6 The CRL-Type tensile testing machine used and the effective carriage mass, and
13.2.7 The testing conditions, if other than standard.
14. Precision and Bias
14.1 Summary-In comparing two averages, the differences should not exceed the following
critical differences in 95 cases out of 100 where all of the observations are taken by the same
well-trained operator using the same piece of test equipment and specimens randomly drawn
from the sample of material.

Tension 0.25 lbf (1.1 N) for averages of 4

Elongation 3.50 % for averages of 4

The size of the differences is likely to be affected adversely by different circumstances. The true
values of tension and elongation can be defined only in terms of specific test methods. Within
this limitation, the procedures in this test method for determining these properties have no
known bias. Sections 14.2 through 14.4 explain the basis for this summary and for evaluations
made under other conditions.
14.2 Interlaboratory Test Data6-An interlaboratory test

was run in 1971 in which randomly drawn samples of four materials were tested for elongation
and tension in each of four laboratories. Each laboratory used one operator each of whom
tested five specimens of material. An interlaboratory test was run in 1976 in which randomly
drawn samples of three materials were tested for tension only in each of four laboratories. Each
laboratory used one operator, each of whom tested six specimens of each material. The
components of variance for elongation from the 1971 tests and for tension from the 1976 tests
expressed as standard deviations were calculated to be the values listed in Table 2.
14.3 Precision-For the components of variance in Table 2, two averages of observed values
should be considered significantly different at the 95 % probability level if the difference equals
or exceeds the critical differences tabulated in Table 3.

NOTE 4-Since the laboratory tests included only four laboratories, between-Iaboratory precision
data should be used with special caution.
NOTE 5- The tabulated values of the critical differences should be considered to be a general
statement, particularly with respect to between-Iaboratory precision. Before a meaningful
statement can be made about two specific laboratories, the amount of statistical bias, if any,
between them must be established, with each comparison being based on recent data obtained
on specimens taken from a lot of material of the type being evaluated so as to be as nearly
homogeneous as possible and then randomly assigned in equal numbers to each of the
laboratories.
14.4 Bias- The true values of the properties listed in Tables 1,2, and 3 can only be defined in
terms of specific test methods. Within this limitation, the procedures in Test Method D 1775 for
determining those properties have no
known bias.
15. Keywords
15. elastic fabric; elongation, strand; tension (tensile) properties tests

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