ASTM D732 – Standard Test Method for Shear Strength of Plastics by Punch Tool
Significance and Use
4.1 Shear strength obtained by the use of punch-type tooling is one of the recognized methods of comparing materials, or obtaining data for engineering design purposes, or both. However, it must be recognized that for end-use applications there are likely to be many factors not taken into account in this test method, such as stress-concentrating geometries and rates of shear, which can profoundly affect the measured shear strength. Moreover, the fact that the shear strength is calculated by dividing the load by the area of the sheared edge (punch circumference X specimen thickness) does not interpret as indicating the shear strength value so obtained is solely a material property, independent of thickness.
4.2 For many materials, it is possible that there is a specification that requires the use of this test method, but with some procedural modifications that take precedence when adhering to the specification. Therefore, it is advisable to refer to that material specification before using this test method. Table 1 of Classification System D4000 lists the ASTM materials standards that currently exist.
1.1 This test method covers the procedure for determining the shear strength of plastics in the form of sheets, plates, and molded shapes in thicknesses from 1.27 to 12.7 mm (0.050 to 0.500 in.).
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.