ASTM D 256 - 04 Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics

American Society for Testing and Materials (ASTM). Current edition approved May 1, 2004. Published June 2004. 20 p. These test methods cover the determination of the resistance of plastics to standardized (see Note 1) pendulumtype hammers, mounted in standardized machines, in breaking standard specimens with one pendulum swing (see Note 2). The standard tests for these test methods require specimens made with a milled notch (see Note 3). In Test Methods A, C, and D, the notch produces a stress concentration that increases the probability of a brittle, rather than a ductile, fracture. In Test Method E, the impact resistance is obtained breakage by flexural shock as indicated by the energy extracted from by reversing the notched specimen 180° in the clamping vise. The results of all test methods are reported in terms of energy absorbed per unit of specimen width or per unit of crosssectional area under the notch. (See Note
4.).