What is a pressure test?
The behavior of a material under compressive load is examined in a compression test. In this test, the specimen is subjected to a uniformly increasing force in the form of a defined compression sample. Depending on the requirement or material, the specimen is stressed until it breaks, cracks or reaches a defined compression. It is also possible to apply a cyclical load to characterize fatigue properties in the pressure-swell range.
The specimen is usually loaded with compression platens. However, there are also specific devices, e.g. for the compression testing of composite materials, such as the Celanese device or the HCCF device.
Typical material properties or results from a compression test are the stress-strain diagram, the yield strength, the stress at a certain value of strain or compressive strength.
Why are pressure tests carried out?
Compression tests are used to characterize materials for the design of parts or components in terms of technical safety. Applications at Suisse Technologie Partners AG include, for example, the characterization of rigid foams used as core materials in sandwich constructions.
Important standards for compression tests on rigid foams are:
ISO 844, EN 826, ASTM D 1621
Compression test on rigid foam according to ISO 844
The rigid foams mentioned above are often characterized in a compression test according to ISO 844. In this process, the compressive strength, the associated compression, the compressive stress at 10% relative compression and the compression modulus are determined. The compression modulus is determined from the stress-strain curve. This standard describes various methods for measuring compression. The comparability of the determined values is only given when the same test standard, the same procedure and identical sample geometries are used. This must be taken into account when comparing values from different laboratories.
While the displacement of the compression plates is measured in procedure A, the deformation is measured directly on the test piece in procedure B. In particular, it must be kept in mind with procedure B that an inhomogeneous deformation of the test piece due to mechanical instabilities can lead to very different results.
Example applications for pressure tests
pressure tests for technical safety
Compression tests are carried out at Suisse TP on various universal testing machines. The force range varies from a few N up to 500 kN. Components such as crash boxes in the automotive sector can also be tested in compression. Thanks to its many years of experience as a former research laboratory of Alcan and 3A Composites, Suisse TP has extensive expertise in the characterization of materials and components.
Find out more about our expertise in the field of technical security
