ASTM D3043-00(2011)
(Test Method)Standard Test Methods for Structural Panels in Flexure
Standard Test Methods for Structural Panels in Flexure
SIGNIFICANCE AND USE
These methods give the flexural properties, principally strength and stiffness, of structural panels. These properties are of primary importance in most structural uses of panels whether in construction for floors, wall sheathing, roof decking, concrete form, or various space plane structures; packaging and materials handling for containers, crates, or pallets; or structural components such as stress-skin panels.
To control or define other variables influencing flexure properties, moisture content and time to failure must be determined. Conditioning of test material at controlled atmospheres to control test moisture content and determination of specific gravity are recommended. Comparisons of results of plywood, veneer composites, and laminates with solid wood or other plywood constructions will be greatly assisted if the thickness of the individual plies is measured to permit computation of section properties.
SCOPE
1.1 These test methods determine the flexural properties of strips cut from structural panels or panels up to 4 by 8 ft in size. Structural panels in use include plywood, waferboard, oriented strand board, and composites of veneer and of wood-based layers. Four methods of tests are included:
Sections Method ACenter-Point Flexure Test5 Method BTwo-Point Flexure Test 6 Method CPure Moment Test 7 Method DFlexure Test for Quality Assurance8
The choice of method will be dictated by the purpose of the test, type of material, and equipment availability. All methods are applicable to material that is relative uniform in strength and stiffness properties. Only Method C should be used to test material suspected of having strength or stiffness variations within a panel caused by density variations, knots, knot-holes, areas of distorted grain, fungal attack, or wide growth variations. However, Method B may be used to evaluate certain features such as core gaps and veneer joints in plywood panels where effects are readily projected to full panels. Method C generally is preferred where size of test material permits. Moments applied to fail specimens tested by Method A, B or D in which large deflections occur can be considerably larger than nominal. An approximate correction can be made.
1.2 Method A, Center-Point Flexure Test—This method is applicable to material that is uniform with respect to elastic and strength properties. Total deflection, and modulus of elasticity computed from it, include a relatively constant component attributable to shear deformation. It is well suited to investigations of many variables that influence properties uniformly throughout the panel in controlled studies and to test small, defect-free control specimens cut from large panels containing defects tested by the large-specimen method.
1.3 Method B, Two-Point Flexure Test—This method, like Method A, is suited to the investigation of factors that influence strength and elastic properties uniformly throughout the panel, in controlled studies, and to testing small, defect free control specimens cut from large specimens tested by Method C. However, it may be used to determine the effects of finger joints, veneer joints and gaps, and other features which can be placed entirely between the load points and whose effects can be projected readily to full panel width. Deflection and modulus of elasticity obtained from this method are related to flexural stress only and do not contain a shear component. Significant errors in modulus of rupture can occur when nominal moment is used (see Appendix X1).
1.4 Method C, Pure Moment Test—This method is ideally suited for evaluating effects of knots, knot-holes, areas of sloping grain, and patches for their effect on standard full-size panels. It is equally well suited for testing uniform or clear material whenever specimen size is adequate. Measured deformation and elastic constants are free of shear deformation effects; and panels can be bent to large deflection...
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Designation: D3043 − 00 (Reapproved 2011)
Standard Test Methods for
Structural Panels in Flexure
This standard is issued under the fixed designation D3043; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope strength and elastic properties uniformly throughout the panel,
in controlled studies, and to testing small, defect free control
1.1 These test methods determine the flexural properties of
specimens cut from large specimens tested by Method C.
stripscutfromstructuralpanelsorpanelsupto4by8ftinsize.
However, it may be used to determine the effects of finger
Structural panels in use include plywood, waferboard, oriented
joints, veneer joints and gaps, and other features which can be
strand board, and composites of veneer and of wood-based
placed entirely between the load points and whose effects can
layers. Four methods of tests are included:
be projected readily to full panel width. Deflection and
Sections
modulus of elasticity obtained from this method are related to
Method A—Center-Point Flexure Test 5
flexural stress only and do not contain a shear component.
Method B—Two-Point Flexure Test 6
Significant errors in modulus of rupture can occur when
Method C—Pure Moment Test 7
nominal moment is used (see Appendix X1).
Method D—Flexure Test for Quality Assurance 8
1.4 Method C, Pure Moment Test—This method is ideally
The choice of method will be dictated by the purpose of the
suited for evaluating effects of knots, knot-holes, areas of
test, type of material, and equipment availability. All meth-
sloping grain, and patches for their effect on standard full-size
ods are applicable to material that is relative uniform in
panels. It is equally well suited for testing uniform or clear
strength and stiffness properties. Only Method C should be
material whenever specimen size is adequate. Measured defor-
used to test material suspected of having strength or stiffness
mation and elastic constants are free of shear deformation
variations within a panel caused by density variations, knots,
effects; and panels can be bent to large deflections without
knot-holes, areas of distorted grain, fungal attack, or wide
incurringerrorsfromhorizontalforcecomponentsoccurringin
growth variations. However, Method B may be used to
other methods. Specimen size and span above certain mini-
evaluate certain features such as core gaps and veneer joints
mums are quite flexible. It is preferred when equipment is
in plywood panels where effects are readily projected to full
available.
panels. Method C generally is preferred where size of test
material permits. Moments applied to fail specimens tested
1.5 Method D, Flexure Test for Quality Assurance—This
by Method A, B or D in which large deflections occur can
method, like Method A, is well suited to the investigation of
be considerably larger than nominal. An approximate correc-
factors that influence bending strength and stiffness properties.
tion can be made.
Also like Method A, this method uses small specimens in a
1.2 Method A, Center-Point Flexure Test—This method is
center-pointsimplespantestconfiguration.Thismethodusesa
applicabletomaterialthatisuniformwithrespecttoelasticand
span to depth ratio, specimen width, test fixture and test speed
strength properties. Total deflection, and modulus of elasticity
that make the method well suited for quality assurance. The
computed from it, include a relatively constant component
method is frequently used for quality assurance testing of
attributable to shear deformation. It is well suited to investi-
oriented strand board.
gations of many variables that influence properties uniformly
1.6 All methods can be used to determine modulus of
throughout the panel in controlled studies and to test small,
elasticity with sufficient accuracy. Modulus of rupture deter-
defect-free control specimens cut from large panels containing
mined by Methods A, B or D is subject to errors up to and
defects tested by the large-specimen method.
sometimes exceeding 20% depending upon span, loading, and
1.3 Method B, Two-Point Flexure Test—This method, like
deflectionatfailureunlessmomentiscomputedintherigorous
MethodA,issuitedtotheinvestigationoffactorsthatinfluence
manner outlined in Appendix X1 or corrections are made in
other ways. These errors are not present in Method C.
These methods are under the jurisdiction of ASTM Committee D07 on Wood
1.7 Whencomparisonsaredesiredbetweenresultsofspeci-
and are the direct responsibility of Subcommittee D07.03 on Panel Products.
men groups, it is good practice to use the same method of test
Current edition approved Nov. 1, 2011. Published November 2011. Originally
for all specimens, thus eliminating possible differences relat-
approved in 1972. Last previous edition approved in 2000 as D3043–00 (2006).
DOI: 10.1520/D3043-00R11. able to test method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3043 − 00 (2011)
1.8 This standard does not purport to address all of the thickness of material, and the width shall be 1 in. (25 mm) for
safety concerns, if any, associated with its use. It is the depths less than ⁄4 in. (6 mm) and 2 in. (50 mm) for greater
responsibility of the user of this standard to establish appro- depths (Note 1).When the principal direction of the face plies,
priate safety and health practices and determine the applica- laminations,strands,orwafersisparalleltothespan,thelength
bility of regulatory limitations prior to use. of the specimen (Note 2) shall be not less than 48 times the
depth plus 2 in.; when the principal direction of the face plies,
2. Referenced Documents
laminations,strands,orwafersisperpendiculartothespan,the
specimen length shall be not less than 24 times the depth plus
2.1 ASTM Standards:
2 in. (Note 3).
D2395TestMethodsforDensityandSpecificGravity(Rela-
tive Density) of Wood and Wood-Based Materials
NOTE 1—In certain specific instances, it may be necessary or desirable
D4442Test Methods for Direct Moisture Content Measure-
to test specimens having a width greater than 1 or 2 in. (25 or 50 mm).To
ment of Wood and Wood-Based Materials
eliminate plate action when wider specimens are tested, the specimen
widthshallnotexceedonethirdofthespanlengthandprecautionshallbe
D4761Test Methods for Mechanical Properties of Lumber
takentoensureuniformbearingacrosstheentirewidthofthespecimenat
and Wood-Base Structural Material
the load and reaction points.
NOTE 2—In cutting specimens to meet the length requirement, it is not
3. Significance and Use
intended that the length be changed for small variations in thickness.
Rather, it is intended that the nominal thickness of the material under test
3.1 These methods give the flexural properties, principally
should be used for determining the specimen length.
strengthandstiffness,ofstructuralpanels.Thesepropertiesare
of primary importance in most structural uses of panels
5.2.1 Measurements—Measure specimen thickness at mid-
whether in construction for floors, wall sheathing, roof
span at two points near each edge and record the average.
decking, concrete form, or various space plane structures;
Measure to the nearest 0.001 in. (0.02 mm) or 0.3%. Measure
packaging and materials handling for containers, crates, or
width at mid-span to the nearest 0.3%.
pallets; or structural components such as stress-skin panels.
5.2.1.1 When needed for interpretation of test results for
plywood, veneer composites, and laminates measure thickness
3.2 To control or define other variables influencing flexure
of each layer to the nearest 0.001 in. (0.02 mm) at mid-span at
properties, moisture content and time to failure must be
each edge and record the average.
determined. Conditioning of test material at controlled atmo-
spheres to control test moisture content and determination of
5.3 Span—The span shall be at least 48 times the nominal
specific gravity are recommended. Comparisons of results of
depth when the principal direction of the face plies,
plywood,veneercomposites,andlaminateswithsolidwoodor
laminations, strands, or wafers of the test specimen is parallel
other plywood constructions will be greatly assisted if the
to the span and at least 24 times the nominal depth when the
thickness of the individual plies is measured to permit compu-
principal direction of the face plies, laminations, strands, or
tation of section properties.
wafers is perpendicular to the span (Note 3).
NOTE 3—Establishment of a span-depth ratio is required to allow an
4. Control of Moisture Content
accuratecomparisonoftestvaluesformaterialsofdifferentthicknesses.It
4.1 Structural panel samples to be tested at a specific
should be noted that the span is based on the nominal thickness of the
moisture content or relative humidity shall be conditioned to material and it is not intended that the spans be changed for small
variations in thickness.
approximate constant mass in controlled atmospheric condi-
tions before testing. For structural panels used under dry
5.4 End Supports—Reaction points shall be capable of
conditions,arelativehumidityof65 65%atatemperatureof
freely compensating for warp of the test specimen by turning
68 6 6°F (20 6 3°C) is recommended.
laterally in a plane perpendicular to the specimen length so as
to apply load uniformly across its width. Design of end
5. Method A—Center-Point Flexure Test
supports shall place the center of rotation near the neutral axis
5.1 Summary—Aconventionalcompressiontestingmachine
ofthespecimenofaveragethickness.Constructionisshownin
is used to apply and measure a load at mid-span of a small
detail in Fig. 1. Bearing points shall be rounded where they
flexure specimen; and the resulting deflection at mid span is contact the specimen.
measured or recorded. The test proceeds at a constant rate of
5.4.1 Useofbearingplatesisgenerallyrecommendedandis
head motion until either sufficient deflection data in the elastic
required wherever significant local deformation may occur.
range have been gathered or until specimen failure occurs.The
5.4.2 Use of roller bearings or plates and rollers to preclude
specimen is supported on reaction bearings which permit the
friction forces between end support and specimen is recom-
specimen and bearing plate to roll freely over the reactions as
mendedinadditiontotherequirementoflateralcompensation.
the specimen deflects.
Construction of a suitable end support using small roller
bearings in conjunction with a plate which clips to the end of
5.2 Test Specimen—The test specimen shall be rectangular
the specimen is illustrated in Fig. 2 and Fig. 3. The use of a
incrosssection.Thedepthofthespecimenshallbeequaltothe
large ball bearing to provide lateral compensation for warp is
also illustrated. This method is particularly recommended for
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
thin specimens and small loads.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.4.3 As the specimen deflects during test, loads no longer
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. act in the direction assumed in formulas for calculating
D3043 − 00 (2011)
Metric Equiva- Metric Equiva-
Inch-Pound (in.) Inch-Pound (in.)
lents, (mm) lents, (mm)
1 1
⁄16 1.5 1 ⁄4 32
1 1
⁄8 31 ⁄2 38
⁄16 52 50
1 1
⁄4 62 ⁄16 52
⁄8 10 3 76
13 1
⁄32 10.3 5 ⁄2 140
⁄2 12 6 152
⁄8 23 12 305
⁄16 24 24 610
FIG. 1 Apparatus for Static Bending Test Showing Details of
Laterally Adjustable Supports
properties. For a discussion of these errors, their effects, and permissible variation of 625%. Load shall be measured to an
methods for reducing them, refer to Appendix X1.
accuracy of 61% of indicated value or 0.4 percent of full
scale, whichever is larger. Calculate the rate of motion of the
5.5 Loading Block—A loading block having a radius of
movable head as follows:
curvatureofapproximatelyoneandone-halftimesthedepthof
the test specimen for a chord length of not less than twice the
N 5 zL /6d (1)
depth of the specimen shall be used. In cases where excessive
where:
local deformation may occur, suitable bearing plates shall be
N = rate of motion of moving head, in./min (mm/min),
used.Radiusofcurvatureofbearingplateorblockshallnotbe
L = span, in. (mm),
so large as to cause bridging as the specimen bends.
d = depth of beam, in. (mm), and
5.6 Loading Procedure—Apply the load with a continuous
z = unit rate of fiber strain, in./in.·min (mm/mm·min) of
motion of the movable head throughout the test. The rate of
outer fiber length=0.0015.
load application shall be such that the maximum fiber strain
rate is equal to 0.0015 in./in. (mm/mm) per min within a
D3043 − 00 (2011)
FIG. 2 Reaction Bearing for Small Flexure Test Specimens
EI 5 L /48 P/∆ (2)
5.6.1 Measure the elapsed time from initiation of loading to ~ !~ !
maximum load and record to the nearest ⁄2 min.
where:
5.7 Measurement of Deflection—Take data for load-
EI = modulus of elasticity, psi (MPa)×moment of inertia,
4 4
deflection curves to determine the modulus of elasticity,
in. (or mm ),
proportional limit, work to proportional limit, work to maxi-
P/∆ = slope of load—deflection curve, lbf/in. (N/mm),
4 4
mum load, and total work. Take deflections by the methods
I = moment of inertia, in. (mm ), and
indicated in Fig. 4 or Fig. 5, and take readings to the nearest
L = span, in. (mm).
0.001in.(0.02mm).Chooseincrementsofloadsothatnotless
5.8.1.1 Moment of inertia used in the computations in 5.8.1
than 12 and preferably 15 or more readings of load and
maybecalculatedinseveraldifferentwaysdependinguponthe
deflection are taken to the proportional limit.
requirementsoftheinvestigation.Itmaybebasedontheentire
5.7.1 Deflections also may be measured with transducer-
crosssection,mayincludeonlythemomentofinertiaoflayers
type gages and plotted simultaneously against load. In this
parallel to span, or may include all layers weighted in accor-
case, record deflection to an accuracy of at least 1 ⁄2%of
dance with modulus of elasticity in the direction of bending
deformation at proportional limit and the recorded trace below
the proportional limit shall be at least 2 ⁄2 in. (64 mm) long or stress. State clearly the method employed in the report.
⁄4offullscalemeasuredonthedeformationaxis,whicheveris
5.8.2 Calculate maximum moment (S I/c) by the following
b
larger. Similar requirements apply to the load a
...
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