ASTM D3916-08(2016)

3.1 The high axial-tensile strength and the low transverse-compressive strength of pultruded rod combine to present some unique problems in determining the tensile strength of this material with conventional test grips. The high transverse-compressive forces generated in the conventional method of gripping tend to crush the rod, thereby causing premature failure. In this test method, aluminum-alloy tabs contoured to the shape of the rod reduce the compressive forces imparted to the rod, thus overcoming the deleterious influence of conventional test grips.

3.2 Tensile properties are influenced by specimen preparation, strain rate, thermal history, and the environmental conditions at the time of testing. Consequently, where precise comparative results are desired, these factors must be carefully controlled.

3.3 Tensile properties provide useful data for many engineering design purposes. However, due to the high sensitivity of these properties to strain rate, temperature, and other environmental conditions, data obtained by this test method should not, by themselves, be considered for applications involving load-time scales or environmental conditions that differ widely from the test conditions. In cases where such dissimilarities are apparent, the sensitivities to strain rate, including impact and creep, as well as to environment, should be determined over a wide range of conditions as dictated by the anticipated service requirements.

1.1 This test method describes a procedure for determining the tensile properties of pultruded, glass-fiber-reinforced thermosetting plastic rod of diameters ranging from 3.2 mm (¹/₈ in.) to 25.4 mm (1 in.). Little test specimen preparation is required; however, reusable aluminum tab grip adapters (Fig. 1) of appropriate size are required to prevent premature failure of the specimens at the grips.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.3 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. Specific hazards statements are given in Note 3 and Note 4.