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ASTM D638-14
Standard Test Method for Tensile Properties of Plastics
1.1 This test method covers the determination of the tensile properties of unreinforced
and reinforced plastics in the form of standard dumbbell-shaped test specimens when
tested under defined conditions of pretreatment, temperature, humidity, and testing
machine speed.
1.2 This test method is applicable for testing materials of any thickness up to 14
mm (0.55 in.). However, for testing specimens in the form of thin sheeting, including
film less than 1.0 mm (0.04 in.) in thickness, ASTM standard D882 is the preferred
test method. Materials with a thickness greater than 14 mm (0.55 in.) shall be reduced
by machining.
1.3 This test method includes the option of determining Poisson's ratio at room temperature.
NOTE 1 This standard and ISO 527-1 address the same subject matter, but differ in
technical content.
NOTE 2 This test method is not intended to cover precise physical procedures. It
is recognized that the constant rate of crosshead movement type of test leaves much
to be desired from a theoretical standpoint, that wide differences may exist between
rate of crosshead movement and rate of strain between gage marks on the specimen,
and that the testing speeds specified disguise important effects characteristic of
materials in the plastic state. Further, it is realized that variations in the thicknesses
of test specimens, which are permitted by these procedures, produce variations in
the surface-volume ratios of such specimens, and that these variations may influence
the test results. Hence, where directly comparable results are desired, all samples
should be of equal thickness. Special additional tests should be used where more
precise physical data are needed.
NOTE 3 This test method may be used for testing phenolic molded resin or laminated
materials. However, where these materials are used as electrical insulation, such
materials should be tested in accordance with Test Methods D229 and Test Method D651.
NOTE 4 For tensile properties of resin-matrix composites reinforced with oriented
continuous or discontinuous high modulus >20-GPa (>3.0?×?106-psi) fibers, tests shall
be made in accordance with Test Method D3039/D3039M.
1.4 Test data obtained by this test method have been found to be useful in engineering
design. However, it is important to consider the precautions and limitations of this
method found in Note 2 and Section 4 before considering these data for engineering
design.
1.5 The values stated in SI units are to be regarded as standard. The values given
in parentheses are for information only.
1.6 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.
Extracted, with permission, from ASTM D638 Standard Test Method for Tensile Properties
of Plastics, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken,
PA 19482. A copy of the complete standard may be purchased from ASTM International,
www.astm.org.