Compression Properties ASTM D695, ISO 604
Understand compression strength and modulus of plastics materials used in various engineering applications using ASTM D695.Scope:
Compressive properties describe the behavior of a material when it is subjected to a compressive load. Loading is at a relatively low and uniform rate. Compressive strength and modulus are two common values generated by the test.
The specimen is placed between compressive plates parallel to the surface. The specimen is then compressed at a uniform rate. The maximum load is recorded along with stress-strain data. An extensometer attached to the front of the fixture is used to determine modulus.
Specimens can either be blocks or cylinders. For ASTM, the typical blocks are 12.7 x 12.7 x 25.4mm (½ by ½ by 1 in). and the cylinders are 12.7mm (½ in) in diameter and 25.4mm (1 in) long. For ISO, the preferred specimens are 50 x 10 x 4mm for modulus and 10 x 10 x 4mm for strength.
Compressive strength and modulus are two useful calculations.
Compressive strength =
maximum compressive load
minimum cross-sectional area
Compressive modulus =
change in stress
change in strain
**Please note that this test description is intentionally generic in nature and aimed at providing a descriptive summary to enhance test understanding. Due to copyright restrictions, we are not able to provide copies of standards. Standards can be obtained from appropriate standards authorities.
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