ASTM D3043-17 pdf download.Standard Test Methods for Structural Panels in Flexure.
3. Significance and Use
3.1 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.
3.2 To control or define other variables influencing flexure properties, moisture content and time to failure must be determined. Conditioning of test material at controlled atmo- spheres 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 compu- tation of section properties.
4. Control of Moisture Content 4.1 Structural panel samples to be tested at a specific moisture content or relative humidity shall be conditioned to approximate constant mass in controlled atmospheric condi- tions before testing. For structural panels used under dry conditions, a relative humidity of65 6 5 % at a temperature of 68 6 6°F (20 6 3°C) is recommended.
5. Method A—Center-Point Flexure Test
5.1 Summary—Aconventional compression testing machine is used to apply and measure a load at mid-span of a small flexure specimen; and the resulting deflection at mid span is measured or recorded. The test proceeds at a constant rate of head motion until either sufficient deflection data in the elastic range have been gathered or until specimen failure occurs. The specimen is supported on reaction bearings which permit the specimen and bearing plate to roll freely over the reactions as the specimen deflects.
5.2 Test Specimen—The test specimen shall be rectangular in cross section. The depth ofthe specimen shall be equal to the thickness of material, and the width shall be 1 in. (25 mm) for depths less than 1 ⁄ 4 in. (6 mm) and 2 in. (50 mm) for greater depths (Note 1). When the principal direction of the face plies, laminations, strands, or wafers is parallel to the span, the length 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, laminations, strands, or wafers is perpendicular to the span, the specimen length shall be not less than 24 times the depth plus 2 in. (Note 3). N OTE 1—In certain specific instances, it may be necessary or desirable to test specimens having a width greater than 1 or 2 in. (25 or 50 mm). To eliminate plate action when wider specimens are tested, the specimen width shall not exceed one third ofthe span length and precaution shall be taken to ensure uniform bearing across the entire width of the specimen at the load and reaction points. N OTE 2—In cutting specimens to meet the length requirement, it is not intended that the length be changed for small variations in thickness. Rather, it is intended that the nominal thickness of the material under test should be used for determining the specimen length.
5.2.1 Measurements—Measure specimen thickness at mid- span at two points near each edge and record the average. Measure to the nearest 0.001 in. (0.02 mm) or 0.3 %. Measure width at mid-span to the nearest 0.3 %.
5.2.1.1 When needed for interpretation of test results for plywood, veneer composites, and laminates measure thickness of each layer to the nearest 0.001 in. (0.02 mm) at mid-span at each edge and record the average.
5.3 Span—The span shall be at least 48 times the nominal depth when the principal direction of the face plies, laminations, strands, or wafers of the test specimen is parallel to the span and at least 24 times the nominal depth when the principal direction of the face plies, laminations, strands, or wafers is perpendicular to the span (Note 3). N OTE 3—Establishment of a span-depth ratio is required to allow an accurate comparison oftest values for materials ofdifferent thicknesses. It should be noted that the span is based on the nominal thickness of the material and it is not intended that the spans be changed for small variations in thickness.
5.4 End Supports—Reaction points shall be capable of freely compensating for warp of the test specimen by turning laterally in a plane perpendicular to the specimen length so as to apply load uniformly across its width. Design of end supports shall place the center of rotation near the neutral axis ofthe specimen ofaverage thickness. Construction is shown in detail in Fig. 1. Bearing points shall be rounded where they contact the specimen.ASTM D3043 pdf download.