ASTM D – Air Permeability of Textile Fabrics . ASTM D – Standard Test Method for Flexural Properties Testing of Unreinforced and Reinforced. The Flexural test ASTM D measures the force required to bend a plastic beam under a four point loading system. The test method is used for reinforced or . ASTM D tests flexural properties of unreinforced and reinforced plastics and electrical insulating materials by four point bending. Learn more.
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This standard has either been satm and replaced by a new version or discontinued. D62722 number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. These test methods are generally applicable 6d272 rigid and semirigid materials.
This test method utilizes a four point loading system applied to a simply supported beam. Procedure B may be used for measurement of? The values provided in parentheses are for information only. 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. Summary of Test Method 4. The distance between the loading noses the load span is either one third or one half of the support span see Fig.
A support span-to-depth ratio of Current edition approved July 10, Originally published as D — Last previous edition D — It shall be equipped d272 a de? The load indicating mechanism shall be essentially free from inertial lag at the crosshead rate used.
C6272 accuracy of the testing machine shall be veri? In order to avoid excessive indentation, or failure due to stress concentration directly under the loading noses, the radii of the loading noses and supports shall be 5. D66272 other loading noses and supports are used they must comply with the following requirements: They shall be this large if signi?
The arc of the loading noses in contact with the specimen shall be sufficiently large to prevent contact of the specimen with the sides of the noses see Fig. NOTE 2—Test data have shown that the loading x6272 and support dimensions can in? The loading noses dimension has the greater in? Dimensions of loading noses and supports must be speci? The major difference adtm four point and three point bending modes is the location of the maximum bending moment and maximum axial?
In four point bending the maximum axial? In three point bending the maximum axial? Any test specimen preparation, conditioning, dimensions, or testing parameters covered in the material speci? If there are no material speci? Table 1 in Classi? The device shall automatically asrm continuously record the de? All width and thickness measurements of rigid and semi-rigid plastics may be measured with a hand micrometer with ratchet. A suitable instrument for measuring the thickness of non-rigid test specimens shall have: The actual dimensions used in Section 12 Calculation shall be measured in accordance with Test Method D NOTE 3—Any necessary polishing of specimens shall be done only in the lengthwise direction of the specimen.
For edgewise tests, the width of the specimen shall be the thickness d272 the sheet, and the depth shall not exceed the width see Notes 5 and 6. For all tests, the support span shall be 16 tolerance 6 1 times the depth of the beam.
Instron ASTM D Flexural Properties of Plastics and Electrical Insulating Materials – Instron
Specimen width shall not exceed one fourth of the support span for specimens greater than 3. Overhang shall be sufficient to prevent the specimen from slipping through the supports. NOTE 4—Whenever possible, the original surface of the sheet shall be unaltered. Adtm, where testing machine limitations make it impossible to follow the above criterion on the unaltered sheet, qstm or both surfaces shall be machined to provide the desired dimensions, and the location of the specimens with reference to the total depth shall be noted.
The value obtained on specimens with machined surfaces may differ from those obtained on specimens with original surfaces. When only one surface was machined, it must be stated whether the machined surface was on the tension or compression side of the beam. NOTE 5—Edgewise tests are not applicable for sheets that are so thin that specimens meeting these requirements cannot be cut. If specimen depth exceeds the width, buckling may occur.
The support span-to-depth ratio shall be chosen such that failures occur in the outer? Three recommended support span-todepth ratios are 16, 32, and 40 to 1. When laminated materials exhibit low compressive strength perpendicular to the laminations, they shall be loaded with a large radius loading noses up to 1.
Flexural Properties by Four-Point Bending ASTM D
Thicker specimens should be avoided if they exhibit signi? Three recommended support span-to-depth s6272 are However, for some highly anisotropic composites, shear deformation can signi? Hence, for these materials, an increase in span-to-depth ratio to It should also be noted that the?
NOTE 8—As a general rule, support span-to-depth ratios of 16 to 1 are satisfactory when the ratio of the tensile strength to shear strength is less than 8 to 1, but the support span-to-depth ratio must be increased for composite laminates having relatively low shear strength in the plane of the laminate and relatively high tensile strength parallel to the support span.
NOTE 6—Use of the formulas for simple beams cited in these test astn for calculating results presumes that beam width is small in comparison with the support span. Therefore, the formulas do not apply rigorously to these dimensions.
NOTE 7—Where machine sensitivity is such that specimens of these dimensions cannot be measured, wider specimens or shorter support spans, or both, may be used, provided the support span-to-depth ratio is at least 14 to 1.
All dimensions must be stated in the report see also Note 6. Number of Test Specimens 8. Measure the width and depth of the specimen to the nearest 0.
For specimens less than 2. These measurements shall be made in accordance with Test Method D Use the measured span for all calculations. See Annex A2 for information on the determination of and setting of the span. Do not use the movement of the loading noses relative to the supports. Make appropriate corrections for indentation in the specimens and de? For a load span of one half of the support span: Z shall equal 0. This parallelism may be checked by means of a plate containing parallel grooves into which the loading noses and supports will?
Center the specimen on the supports, with the long axis of the specimen perpendicular to the loading noses and supports.
The loading nose assembly shall be of the type which will not rotate. Retests shall be made for any specimen on which values atm not calculated. Calculation NOTE 11—In determination of the calculated value of some of the properties listed in this section it is necessary to determine if the toe compensation see Annex A1 adjustment must be made.
This toe compensation correction shall be made only when it has been shown that the toe region of the curve is due to the takeup of slack, alignment, or seating of the specimen and not an authentic material response. D This stress may be atsm for any point on the loadde? NOTE 12—Eq 5 and 6 apply strictly to materials for which the stress is linearly proportional to strain up to the point of rupture and for which the strains are small. Since this is not always the case, a slight error will be introduced 6d272 the use of this equation.
The equation will, however, be valid for comparison data and speci?
It should be noted that the maximum stress may not occur in the outer? Thus, Eq 5 and 6 yield an apparent strength based on homogeneous beam theory. This apparent strength is highly dependent on the ply-stacking sequence for highly orthotropic laminates.
Asmt 13—The above calculation is not valid if the specimen is slipping excessively between the supports. In such cases, the? The value of the offset must astn given whenever this property is calculated. NOTE 16—This value may differ from? Both methods of calculation are described in the annex to Test Method D It is calculated by drawing a tangent to the steepest initial straight-line portion of the load-de?
NOTE 14—When large support span-to-depth ratios are used, signi? An approximate correction factor is given in Eq 7 and 8 to correct for these end forces in large support span-to-depth ratio beams where relatively large de? NOTE 15—The limitations de?
It is calculated in accordance with Eq 5, Eq 6, Eq 7, and Eq 8 by letting P equal the load at the moment of break. If the material does not break, this part of c6272 test is not applicable. In this case, it is suggested that yield strength, if applicable, be calculated and that the corresponding strain be reported also see d627 Flexural strength should be determined on a separate set of replicate specimens at a lower span-to-depth ratio that induces tensile failures in the outer?
D beam along its lower face. It shall be expressed in megapascals pounds per square inch. The selected point is generally chosen at astmm speci? It is calculated in accordance with Eq 11 or Eq 12 by letting m equal the slope of the secant to the load-de? Precision and Bias