Standard Test Method for Shear Strength (Dynamic Method) of Hook and Loop Touch Fasteners

SIGNIFICANCE AND USE
This test method gives a measure of a key property of hook and loop touch fasteners which is of interest to users of such devices. This is a means of determining the resistance to separation when forces are applied parallel to the plane of the fastener.  
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 purchaser and the supplier 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 which are as homogenous as possible and which are from a lot of hook and loop 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 and an acceptable probability level chosen by the two parties before the testing began. If a 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.
SCOPE
1.1 This test method measures the shear strength of hook and loop touch (CRE) fasteners using a recording constant rate of extension tensile testing machine.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3 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.

General Information

Status
Historical
Publication Date
31-May-2010
Technical Committee
Drafting Committee
Current Stage
Ref Project

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ASTM D5169-98(2010) - Standard Test Method for Shear Strength (Dynamic Method) of Hook and Loop Touch Fasteners
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D5169 −98(Reapproved 2010)
Standard Test Method for
Shear Strength (Dynamic Method) of Hook and Loop Touch
Fasteners
This standard is issued under the fixed designation D5169; 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 touch fasteners in which the fastening strength in the shear
mode (that is, against forces applied in the plane of the
1.1 This test method measures the shear strength of hook
fastener) substantially exceeds the fastening strength in the
and loop touch (CRE) fasteners using a recording constant rate
peel mode (that is, against forces applied perpendicular to the
of extension tensile testing machine.
planes of the two components of the fastener).
1.2 The values stated in inch-pound units are to be regarded
3.1.2 shear strength, n—the resistance to forces that cause,
as standard. The values given in parentheses are mathematical
or tend to cause, two contiguous parts of a body to slide
conversions to SI units that are provided for information only
relatively to each other in a direction parallel to their plane of
and are not considered standard.
contact.
1.3 This standard does not purport to address all of the
3.2 For definitions of other textile terms used in this test
safety concerns, if any, associated with its use. It is the
method, refer to Terminology D123.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Summary of Test Method
bility of regulatory limitations prior to use.
4.1 An area of hook surface is applied to an area of loop
2. Referenced Documents
surface with controlled engagement pressure. This combina-
2.1 ASTM Standards:
tion is subjected to a dynamic shear force acting parallel to the
D76 Specification for Tensile Testing Machines for Textiles surfaces of the specimens.
D123 Terminology Relating to Textiles
D618 Practice for Conditioning Plastics for Testing
5. Significance and Use
5.1 This test method gives a measure of a key property of
3. Terminology
hook and loop touch fasteners which is of interest to users of
3.1 Definitions:
such devices. This is a means of determining the resistance to
3.1.1 hook and loop fastener—a touch fastener, comprised
separation when forces are applied parallel to the plane of the
of two flexible mating strips, the surface of one mating strip
fastener.
being covered with tiny, stiff protrusions shaped like hooks
5.2 In the case of a dispute arising from differences in
which engage the other mating strip which is covered with
reported test results when using this test method for acceptance
pliable loops.
testing of commercial shipments, the purchaser and the sup-
3.1.1.1 Discussion—This fastener comprises a non-adhesive
plier should conduct comparative tests to determine if there is
method of joining two materials where ready adjustment and
a statistical bias between their laboratories. Competent statis-
removal is desirable and fastening is accomplished by pressing
tical assistance is recommended for the investigation of bias.
the mating strips together and separation is accomplished by
As a minimum, the two parties should take a group of test
simply peeling apart. Terms herein referring to hook and loop
specimens which are as homogenous as possible and which are
fastening systems shall be construed to include other types of
from a lot of hook and loop of the type in question. The test
specimens should then be randomly assigned in equal numbers
This test method is under the jurisdiction ofASTM Committee D13 on Textiles
to each laboratory for testing.The average results from the two
and is the direct responsibility of Subcommittee D13.54 on Subassemblies.
laboratories should be compared using Student’s t-test and an
Current edition approved June 1, 2010. Published September 2010. Originally
acceptable probability level chosen by the two parties before
approved in 1991. Last previous edition approved in 2004 as D5169 – 98(2004).
DOI: 10.1520/D5169-98R10.
the testing began. If a bias is found, either its cause must be
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
found and corrected or the purchaser and the supplier must
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
agree to interpret future test results in the light of the known
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. bias.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5169−98 (2010)
6. Apparatus 8.1.1 Remove the outer lap of each roll before selecting the
required number of strips, hook and loop, 4 in. 6 ⁄4 in.
6.1 Roller—consisting of a smooth steel surface, approxi-
(102 6 6 mm) long.
3 1
mately 4 ⁄4 in. (21 mm) in diameter, 2 ⁄4 in. (57 mm) wide, and
8.1.2 Eachspecimenismarkedwithanarrow(↑)pointingin
equippedwithahandle,length4 ⁄8in.(105mm),forpropelling
the direction that the specimen is unwound from the roll. This
the roller back and forth without adding additional weight to
arrow is marked on the specimen on the leading end as it is
the specimen being rolled (see Fig. 1). The weight of the roller
unwound from the roll.The arrow (↑) indicates the direction of
(including the handle) is 11 lbs. 6 ⁄4 lb (4994 6 114 g).
the hooks and loops of the specimens.
6.2 Testing Machine—A constant rate of extension (CRE)
8.1.3 Select the sample consisting of the four (4) contiguous
tensile tester shall be used. The tester shall have two clamps
specimens as described in 8.1.1 and mark it with the appropri-
with centers in the same plane, parallel to the direction of the
ate identification (roll number, lot number, date, and so forth).
motion of the stressing clamp, and so aligned that they will
There are four (4) possible direction configurations of closure
hold the specimen ends wholly in the same plane; a means of
as shown in Fig. 2. The four specimens of hook and loop
moving the stressing clamp at a uniform rate of 12.0 6 0.5
selected will be used to characterize the shear strength of each
in./min (305 6 13 mm/min); an autographic device for record-
of the configurations.
ing the maximum load.
6.2.1 The instrument shall be calibrated to an accuracy of
9. Conditioning
1.0 % of the full scale and the scale range used for the test shall
9.1 Condition the specimens in an atmosphere for testing of
be such that the main test falls within 20 to 80 % of full range.
23 6 2°C (73.4°F 6 3.6°F) and 50 6 5 % relative humidity as
described in Practice D618 for a period of 24 h or until the
7. Sampling
specimens reach moisture equilibrium. Lay specimens flat with
7.1 Select the test samples so as to be as representative of
the functio
...

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