ASTM D143-94(2007)
(Test Method)Standard Test Methods for Small Clear Specimens of Timber
Standard Test Methods for Small Clear Specimens of Timber
SIGNIFICANCE AND USE
These methods cover tests on small clear specimens of wood that are made to provide the following:
4.1.1 Data for comparing the mechanical properties of various species,
4.1.2 Data for the establishment of correct strength functions, which in conjunction with results of tests of timbers in structural sizes (see Methods D 198 and Test Method D 4761), afford a basis for establishing allowable stresses, and
4.1.3 Data to determine the influence on the mechanical properties of such factors as density, locality of growth, position in cross section, height of timber in the tree, change of properties with seasoning or treatment with chemicals, and change from sapwood to heartwood.
SCOPE
1.1 These methods cover the determination of various strength and related properties of wood by testing small clear specimens.
1.1.1 These methods represent procedures for evaluating the different mechanical and physical properties, controlling factors such as specimen size, moisture content, temperature, and rate of loading.
1.1.2 Sampling and collection of material is discussed in Practice D5536. Sample data, computation sheets, and cards have been incorporated, which were of assistance to the investigator in systematizing records.
1.1.3 The values stated in inch-pound units are to be regarded as the standard. The SI values are given in parentheses and are provided for information only. When a weight is prescribed, the basic inch-pound unit of weight (lbf) and the basic SI unit of mass (Kg) are cited.
1.2 The procedures for the various tests appear in the following order: SectionsPhotographs of Specimens5Control of Moisture Content and Temperature6Record of Heartwood and Sapwood7Static Bending8Compression Parallel to Grain9Impact Bending10Toughness11Compression Perpendicular to Grain12Hardness13Shear Parallel to Grain14Cleavage15Tension Parallel to Grain16Tension Perpendicular to Grain17Nail Withdrawal18Specific Gravity and Shrinkage in Volume19Radial and Tangential Shrinkage20Moisture Determination21Permissible Variations22Calibration23
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.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D143 – 94 (Reapproved 2007)
Standard Test Methods for
Small Clear Specimens of Timber
This standard is issued under the fixed designation D143; 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 Department of Defense.
INTRODUCTION
The need to classify wood species by evaluating the physical and mechanical properties of small
clear specimens has always existed. Because of the great variety of species, variability of the material,
continually changing conditions of supply, many factors affecting test results, and ease of comparing
variables, the need will undoubtedly continue to exist.
In the preparation of these methods for testing small clear specimens, consideration was given both
to the desirability of adopting methods that would yield results comparable to those already available
and to the possibility of embodying such improvements as experience has shown desirable. In view
of the many thousands of tests made under a single comprehensive plan by the U.S. Forest Service,
the former Forest Products Laboratories of Canada (now Forintek Canada Corp.), and other similar
organizations, the methods naturally conform closely to the methods used by these institutions. These
methods are the outgrowth of a study of both American and European experience and methods. The
general adoption of these methods will tend toward a world-wide unification of results, permitting an
interchange and correlation of data, and establishing the basis for a cumulative body of fundamental
information on the timber species of the world.
Descriptionsofsomeofthestrengthtestsrefertoprimarymethodsandsecondarymethods.Primary
methods provide for specimens of 2 by 2-in. (50 by 50-mm) cross-section. This size of specimen has
been extensively used for the evaluation of various mechanical and physical properties of different
species of wood, and a large number of data based on this primary method have been obtained and
published.
The 2 by 2-in. (50 by 50-mm) size has the advantage in that it embraces a number of growth rings,
is less influenced by earlywood and latewood differences than smaller size specimens, and is large
enough to represent a considerable portion of the sampled material. It is advisable to use primary
method specimens wherever possible. There are circumstances, however, when it is difficult or
impossible to obtain clear specimens of 2 by 2-in. cross section having the required 30 in. (760 mm)
length for static bending tests. With the increasing incidence of smaller second growth trees, and the
desirability in certain situations to evaluate a material which is too small to providea2by 2-in.
cross-section, a secondary method which utilizesa1by 1-in. (25 by 25-mm) cross section has been
included. This cross section is established for compression parallel to grain and static bending tests,
while the 2 by 2-in. cross-section is retained for impact bending, compression perpendicular to grain,
hardness, shear parallel to grain, cleavage, and tension perpendicular to grain. Toughness and tension
parallel to grain are special tests using specimens of smaller cross section.
The user is cautioned that test results between two different sizes of specimens are not necessarily
directly comparable. Guidance on the effect of specimen size on a property being evaluated is beyond
the scope of these methods, and should be sought elsewhere.
Where the application, measurement, or recording of load and deflection can be accomplished using
electronic equipment and computerized apparatus, such devices are encouraged, providing they do not
lower the standard of accuracy and reliability available with basic mechanical equipment.
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D143 – 94 (2007)
1. Scope D4442 Test Methods for Direct Moisture Content Measure-
ment of Wood and Wood-Base Materials
1.1 These methods cover the determination of various
D4761 Test Methods for Mechanical Properties of Lumber
strength and related properties of wood by testing small clear
and Wood-Base Structural Material
specimens.
D5536 Practice for Sampling Forest Trees for Determina-
1.1.1 Thesemethodsrepresentproceduresforevaluatingthe
tion of Clear Wood Properties
different mechanical and physical properties, controlling fac-
E4 Practices for Force Verification of Testing Machines
tors such as specimen size, moisture content, temperature, and
rate of loading.
3. Summary of Methods
1.1.2 Sampling and collection of material is discussed in
3.1 The mechanical tests are static bending, compression
Practice D5536. Sample data, computation sheets, and cards
parallel to grain, impact bending toughness, compression
have been incorporated, which were of assistance to the
perpendicular to grain, hardness, shear parallel to grain (Note
investigator in systematizing records.
1), cleavage, tension parallel to grain, tension-perpendicular-
1.1.3 The values stated in inch-pound units are to be
to-grain,andnail-withdrawaltests.Thesetestsmaybemadeon
regarded as the standard. The SI values are given in parenthe-
both green and air-dry material as specified in these methods.
ses and are provided for information only. When a weight is
In addition, methods for evaluating such physical properties as
prescribed, the basic inch-pound unit of weight (lbf) and the
specific gravity, shrinkage in volume, radial shrinkage, and
basic SI unit of mass (Kg) are cited.
tangential shrinkage are presented.
1.2 The procedures for the various tests appear in the
following order:
NOTE 1—The test for shearing strength perpendicular to the grain
(sometimes termed “vertical shear”) is not included as one of the principal
Sections
Photographs of Specimens 5 mechanical tests since in such a test the strength is limited by the shearing
Control of Moisture Content and Temperature 6
resistance parallel to the grain.
Record of Heartwood and Sapwood 7
Static Bending 8
4. Significance and Use
Compression Parallel to Grain 9
Impact Bending 10
4.1 These methods cover tests on small clear specimens of
Toughness 11
wood that are made to provide the following:
Compression Perpendicular to Grain 12
4.1.1 Data for comparing the mechanical properties of
Hardness 13
Shear Parallel to Grain 14
various species,
Cleavage 15
4.1.2 Data for the establishment of correct strength func-
Tension Parallel to Grain 16
tions, which in conjunction with results of tests of timbers in
Tension Perpendicular to Grain 17
Nail Withdrawal 18
structural sizes (see Methods D198 and Test Method D4761),
Specific Gravity and Shrinkage in Volume 19
afford a basis for establishing allowable stresses, and
Radial and Tangential Shrinkage 20
4.1.3 Data to determine the influence on the mechanical
Moisture Determination 21
Permissible Variations 22
properties of such factors as density, locality of growth,
Calibration 23
position in cross section, height of timber in the tree, change of
1.3 This standard does not purport to address all of the properties with seasoning or treatment with chemicals, and
safety concerns, if any, associated with its use. It is the change from sapwood to heartwood.
responsibility of the user of this standard to establish appro-
5. Photographs of Specimens
priate safety and health practices and determine the applica-
5.1 Four of the static bending specimens from each species
bility of regulatory limitations prior to use.
shall be selected for photographing, as follows: two average
2. Referenced Documents
growth, one fast growth, and one slow growth. These speci-
mens shall be photographed in cross section and on the radial
2.1 ASTM Standards:
andtangentialsurfaces.Fig.1isatypicalphotographofacross
D198 Test Methods of Static Tests of Lumber in Structural
section of 2 by 2-in. (50 by 50-mm) test specimens, and Fig. 2
Sizes
is the tangential surface of such specimens.
D2395 Test Methods for Specific Gravity of Wood and
Wood-Based Materials
6. Control of Moisture Content and Temperature
D3043 Test Methods for Structural Panels in Flexure
6.1 Inrecognitionofthesignificantinfluenceoftemperature
D3500 Test Methods for Structural Panels in Tension
and moisture content on the strength of wood, it is highly
desirable that these factors be controlled to ensure comparable
These methods are under the jurisdiction of ASTM Committee D07 on Wood
test results.
and are the direct responsibility of Subcommittee D07.01 on Fundamental Test
6.2 Control of Moisture Content—Specimens for the test in
Methods and Properties.
the air-dry condition shall be dried to approximately constant
Current edition approved April 1, 2007. Published April 2007. Originally
´1
weight before test. Should any changes in moisture content
approved in 1922. Last previous edition approved in 2000 as D143 – 94 (2000) .
DOI: 10.1520/D0143-94R07.
occur during final preparation of specimens, the specimens
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
shall be reconditioned to constant weight before test. Tests
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
shall be carried out in such manner that large changes in
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. moisture content will not occur. To prevent such changes, it is
D143 – 94 (2007)
FIG. 1 Cross Sections of Bending Specimens Showing Different Rates of Growth of Longleaf Pine (2 by 2-in. (50 by 50-mm) Specimens)
FIG. 2 Tangential Surfaces of Bending Specimens of Different Rates of Growth of Jeffrey Pine 2 by 2-in. (50 by 50 by 760-mm)
Specimens
desirablethatthetestingroomandroomsforpreparationoftest secondary method specimens. The actual height and width at
specimens have some means of humidity control. the center and the length shall be measured (see 22.2).
6.3 Control of Temperature—Temperature and relative hu-
8.2 Loading Span and Supports—Use center loading and a
midity together affect wood strength by fixing its equilibrium
span length of 28 in. (710 mm) for the primary method and 14
moisture content. The mechanical properties of wood are also
in. (360 mm) for the secondary method. These spans were
affected by temperature alone. When tested, the specimens
established in order to maintain a minimum span-to-depth ratio
shall be at a temperature of 68 + 6°F (20 + 3°C). The tempera-
of 14. Both supporting knife edges shall be provided with
ture at the time of test shall in all instances be recorded as a
bearing plates and rollers of such thickness that the distance
specific part of the test record.
fromthepointofsupporttothecentralplaneisnotgreaterthan
the depth of the specimen (Fig. 3). The knife edges shall be
7. Record of Heartwood and Sapwood
adjustable laterally to permit adjustment for slight twist in the
7.1 Proportion of Sapwood—The estimated proportion of
specimen (Note 2).
sapwood present should be recorded for each test specimen.
NOTE 2—Details of laterally adjustable supports may be found in Fig.
1 of Methods D3043.
8. Static Bending
8.1 Size of Specimens—The static bending tests shall be 8.3 Bearing Block—Abearing block of the form and size of
made on 2 by 2 by 30 in. (50 by 50 by 760 mm) primary that shown in Fig. 4 shall be used for applying the load for
method specimens or 1 by 1 by 16 in. (25 by 25 by 410 mm) primary method specimens. A block having a radius of 1 ⁄2 in.
D143 – 94 (2007)
FIG. 3 Static Bending Test Assembly Showing Method of Load Application, Specimen Supported on Rollers and Laterally Adjustable
Knife Edges, and Method of Measuring Deflection at Neutral Axis by Means of Yoke and Dial Attachment (Adjustable scale mounted on
loading head is used to measure increments of deformation beyond the dial capacity.)
8.6 Load-Deflection Curves:
8.6.1 Load-deflection curves shall be recorded to or beyond
the maximum load for all static bending tests. The curves shall
be continued to a 6 in. (150 mm) deflection, or until the
specimen fails to support a load of 200 lbf (890 N) for primary
methodspecimensandtoa3in.(76mm)deflectionoruntilthe
specimenfailstosupportaloadof50lbf(220N)forsecondary
method specimens.
8.6.2 Deflections of the neutral plane at the center of the
length shall be taken with respect to points in the neutral plane
above the supports. Alternatively, deflection may be taken
relative to the tension surface at midspan. However, take care
to ensure that vertical displacements which may occur at the
reactions are accounted for.
8.6.3 Within the proportional limit, deflection readings shall
be taken to 0.001 in. (0.02 mm).After the proportional limit is
reached, less refinement is necessary in observing deflections,
butitisconvenienttoreadthembymeansofthedialgage(Fig.
3) until it reaches the limit of its capacity, normally approxi-
mately 1 in. (25 mm). Where deflections beyond 1 in. are
encountered, the deflections may be measured by means of the
scale mounted on the loading head (Fig. 3) and a wire mounted
FIG. 4 Details of Bearing Block for Static Bending Tests
at the neutral axis of the specimen of the side opposite the
yoke. Deflections are read to the nearest 0.01 in. (0.2 mm) at
(38 mm) for a chord length of not less than 2 in. (50 mm) shall 0.10 in. (2.5 mm) intervals and also after abrupt changes in
be used for secondary method specimens. load.
8.4 Placement of Growth Rings—The specimen shall be 8.6.4 The load and deflection of first failure, the maximum
placed so that the load will be applied through the bearing
load, and points of sudden change shall be read and shown on
block to the tangential surface nearest the pith. the curve sheet (Note 3) although they may not occur at one of
8.5 Speed of Testing—The load shall be applied continu-
the regular load or deflection increments.
ously throughout the test at a rate of motion of the movable
NOTE 3—See Fig. 5 for a sample static bending data sheet form.
crosshead of 0.10 in. (2.5 mm)/min (see 22.3), for primary
method specimens, and at a rate of 0.05 in. (1.3 mm)/min for 8.7 Description of Static Bending Failures—Static bending
secondary method specimens. (flexural) failures shall be classified in accordance with the
D143 – 94 (2007)
FIG. 5 Sample Data Sheet for Static Bending Test
appearance of the fractured surface and the manner in which primary method specimens, or 1 by 1 by 4 in. (2
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