Penetration length tests

A wide variety of tests is performed in TMA, which are adapted from physical tests that were used before the instrument became commonly available. These tests may also be modeled or mimicked in TMA, such as heat distortion (Fig. 9) and softening points. Methods to obtain the modulus, compressive viscosity, and penetrative viscosity have been developed. Many of these methods, such as ASTM D648 for example, will specify the stress the sample needs to be exposed to during the run. In D684, a sample is tested at 66 and 264 psi. Most TMAs on the market today have software available that allows them to generate stress—strain curves and to run creep—recovery experiments. Some are also capable of limited types of stress relaxation studies (for example a constant gauge length test " ). 

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