Measurement of Stress-Strain Properties
This chapter reviews the basic concepts and test methods applied to the mechanical testing of rubbers and plastics. It aims to highlight the important concepts and tests often applied in largely product development and quality control programs. The measurement itself is a function of temperature, time, and the particular test method employed, for which there are several. The most widely used instrument for stress-strain measurement is the Instron Tensile Tester. Tests can typically be conducted in one of two modes: using a constant rate of loading or a constant rate of traverse. The purpose of the cage is to reverse the test direction on the test piece while maintaining a tensile force on the load cell that measures the force. In plastics applications, tear tests are applied to films, whereas for rubbers they are applied to standard test sheets of 2-mm nominal thickness.