ISO 844 is used to investigate the compressive behavior of cellular plastics for determining the
compressive strength, compressive strength at pre-defined deformations, compressive modulus, and other aspects of the compressive stress/strain relationship under the conditions defined.
In principle, the test specimen is centrally positioned between the two parallel anvils then compressed along its major axis at a constant rate of displacement until the specimen has deformed as a percentage of the specimen's original height. For this test type, we use the preload feature of Bluehill® 2 Software to determine the anvil height. The load sustained by the specimen is measured during this procedure. To record the test it is important to have a high speed intelligent test data logging rate. This is the transfer rate to the PC of 100Hz or more to capture and record all data.
We used hardened-steel compression anvils used to apply the deformation load to the test specimen. These anvils are fitted to a tensile testing machine, usually of single-column or dual-column table-top design.. Using testing software, such as our Bluehill 2 test method, is ideal for inputting specimen details, setting the desired test control, automatically calculating the desired results and statistics, and producing a test report all in accordance with the standard.
We suggest reviewing ISO 844 to fully understand the test fixture and results requirements.