ASTM D732 Shear Strength of Plastics by Punch Tool Testing Machine

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.