ASTM D638-03 pdf free.Standard Test Method for Tensile Properties of Plastics.
Measure the width and thickness of flat specimens atthe center of each specimen and within 5 mm of each end of thegage length.
Injection molded specimen dimensions may be determined by actual measurement of only one specimen fromeach sample when it has previously been demonstrated that thespecimen-to-specimen variation in width and thickness is lessthan 1 %.
Take the width of specimens produced by a Type IVdie as the distance between the cutting edges of the die in thenarrow section.
Measure the diameter of rod specimens，and theinside and outside diameters of tube specimens, to the nearest0.025 mm [0.001 in.] at a minimum of two points 90° apart;make these measurements along the groove for specimens soconstructed.Use plugs in testing tube specimens, as shown inFig. 2.
Place the specimen in the grips of the testing machine,taking care to align the long axis of the specimen and the gripswith an imaginary line joining the points of attachment of thegrips to the machine.The distance between the ends of thegripping surfaces，when using flat specimens，shall be asindicated in Fig.1.On tube and rod specimens, the location forthe grips shall be as shown in Fig. 2 and Fig.3.Tighten thegrips evenly and firmly to the degree necessary to preventslippage of the specimen during the test, but not to the pointwhere the specimen would be crushed.
Attach the extension indicator. When modulus is beingdetermined, a Class B-2 or better extensometer is required (see5.2.1).
Make simultaneous measurements of load andstrain and record the data. The precision of the value ofPoisson’s Ratio will depend on the number of data points ofaxial and transverse strain taken. It is recommended that thedata collection rate for the test be a minimum of 20 points persecond. This is particularly important for materials having anon linear stress to strain curve.
Set the speed of testing at the proper rate as required inSection 8, and start the machine.ASTM D638 pdf download.