ASTM D1184-98(2020)

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: D1184 − 98 (Reapproved 2020)
Standard Test Method for
Flexural Strength of Adhesive Bonded Laminated
Assemblies
This standard is issued under the fixed designation D1184; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
INTRODUCTION
The accuracy of the results of strength tests of adhesive bonds will depend on the conditions under
which the bonding process is carried out. Unless otherwise agreed upon by the manufacturer and the
purchaser, the bonding conditions shall be prescribed by the manufacturer of the adhesive. In order to
ensure that complete information is available to the individual conducting the tests, the manufacturer
of the adhesive shall furnish numerical values and other specific information for each of the following
variables:
(1) Procedure for preparation of surfaces prior to application of the adhesive, including the moisture
content of wood, the cleaning and drying of metal surfaces, and special surface treatments such as
sanding that are not specifically limited by the pertinent test method.
(2) Complete mixing directions for the adhesive.
(3) Conditions for application of the adhesive including the rate of spread of thickness of film,
number of coats to be applied, whether to be applied to one or both surfaces, and the conditions of
drying where more than one coat is required.
(4) Assembly conditions before application of pressure, including the room temperature, length of
time, and whether open or closed assembly is to be used.
(5) Curing conditions, including the amount of pressure to be applied, the length of time under
pressure, and the temperature of the assembly when under pressure. It should be stated whether this
temperature is that of the glue line or of the atmosphere at which the assembly is to be maintained.
(6) Conditioning procedure before testing, unless a standard procedure is specified, including the
length of time, temperature, and relative humidity.
Arange may be prescribed for any variable by the manufacturer of the adhesive if it can be assumed
by the test operator that any arbitrarily chosen value within such a range or any combination of such
values for several variables will be acceptable to both the manufacturer and the purchaser of the
adhesive.
1. Scope specimen and testing technique were designed to develop a
large portion of shear forces between the laminae of the test
1.1 This test method covers the determination of the com-
piece when the load is applied, rather than to reduce shear
parative properties of either metal or wood adhesive bonded
stress to a minimum as is done in otherASTM test methods for
assemblies when subjected to flexural stresses with standard
flexural properties.This method is not applicable to assemblies
shape specimens and under defined conditions of pretreatment,
made with nonrigid adherends. The data obtained are not
temperature, relative humidity, and testing technique. The test
suitable for design work.
1.2 The values stated in SI units are to be regarded as the
This test method is under the jurisdiction of ASTM Committee D14 on
standard. The values given in parentheses are for information
Adhesives and is the direct responsibility of Subcommittee D14.80 on Metal
Bonding Adhesives.
purposes.
Current edition approved Jan. 1, 2020. Published January 2020. Originally
1.3 This standard does not purport to address all of the
approved in 1951. Last previous edition approved in 2012 as D1184 – 98 (2012).
DOI: 10.1520/D1184-98R20. safety concerns, if any, associated with its use. It is the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1184 − 98 (2020)
responsibility of the user of this standard to establish appro- one and one-half times the specimen depth for a chord length
priate safety, health, and environmental practices and deter- of not less than twice the specimen depth is used.
mine the applicability of regulatory limitations prior to use.
6.3 Supports—A pair of round-nosed supports of the same
1.4 This international standard was developed in accor-
radius as that on the loading piece is used. The span is
dance with internationally recognized principles on standard-
adjustable to 60.13 mm (0.005 in.) within the range of eight
ization established in the Decision on Principles for the
times the thickness of the test specimens (usually a span of 13
Development of International Standards, Guides and Recom-
to 38 mm (0.5 to 1.5 in.)). The support device is mounted on
mendations issued by the World Trade Organization Technical
the one loading part of the testing machine so that the rounded
Barriers to Trade (TBT) Committee.
nose of the loading piece on the other loading part is centered
between the supports.
2. Referenced Documents
6.4 Micrometers—Suitable calibrated micrometers, reading
2.1 ASTM Standards:
to at least 0.025 6 0.001 mm (0.001 6 0.0005 in.) is used for
D907 Terminology of Adhesives
measuring the width and thickness of the test specimen.
E4 Practices for Force Verification of Testing Machines
6.5 Conditioning Room or Desiccators—A conditioning
3. Terminology room capable of maintaining a relative humidity of 50 62%
at 23 6 1.1°C (73.4 6 2°F), or desiccators filled with a
3.1 Definitions—Many terms in this test method are defined
saturatedsaltsolution(Note1)togivearelativehumidityof50
in Terminology D907.
6 2 % at 23 6 1.1°C (73.4 6 2°F).
4. Summary of Test Method
NOTE 1—A saturated solution of calcium nitrate will give approxi-
mately 51 % relative humidity at 23°C in a closed container.
4.1 Test a specimen composed of eight bonded plies as a
simple beam loaded at the mid-span. Test at conditions of
7. Test Specimens
standard temperature and humidity. Specimen flexural proper-
7.1 The specimen is a rectangular piece 38 mm (1.5 in.)
tiesarecomparedbygeneratingmaximumshearstressinmetal
long and 19.1 mm (0.75 in.) wide. The length of the specimen
specimens and flexural strength of wood specimens using
is sufficient to allow an overhang of between 2.5 and 3.8 mm
standard formulas.
(0.1 and 0.15 in.) on each end. The specimens are machined
from laminated panels consisting of eight plies of 0.3-mm
5. Significance and Use
(0.01-in.) thick adherend material. Each ply is coated with
5.1 This test method is designed for both wood and metal
adhesive on both sides with an even spread, and bonded. The
bonded specimens.
mixing procedure, weight of spread, drying conditions, and
assembly time conforms to the manufacturer’s directions. The
5.2 The test method provides a means to compare flexural
properties between assemblies. maximum shear stress is developed at the neutral surface
approximately midway between the top and bottom of the
5.3 The data are reduced to a comparable basis by means of
beam. Thus it is important to have an even number of plies of
the formulas given in 11.1 and 11.2. It is recognized that these
adherend material, so that the adhesive is in the center. Since
formulas do not apply rigidly to tests made in th
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