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Stress relaxation testing ISO 3384-1, ISO 6914

Relaxation is the decrease in counter pressure, which can be measured in a rubber test piece exposed to constant deformation.The deformation method can either be compression or tension.

Relaxation measuring can be done in two different ways. Either the measurements of the original force and the force after different times can be taken at the test temperature, or all measurements are taken at room temperature, while the samples are stored at increased temperature in between these measurements. In certain cases, relaxation measuring is also done in liquids, for example in oil. This is common for, for example, O-rings.

Stress relaxation test systems

Stress relaxation tests are becoming more and more popular for determination of rubber properties.

Elastocon offers equipment for stress relaxation testing of rubber that meets the demands for either continuous or discontinuous testing in both tension and compression, in liquid and air, as well as for different temperature intervals. Meets the requirements in ISO 3384, ISO 6914 and ASTM D6147.

Stress relaxation rigs

Elastocon's EB 02 is a relaxation rig for continuous stress relaxation measurements of rubber in both compression and tension according to ISO 3384, ISO 6914 method A and ASTM D6147. The rig works together with the cell ovens EB 21, EB 22, EB 38 and the programmable temperature cycling cell ovens EB 21LTHTP and EB 17, or with our temperature boxes for test at room temperature and below.

Stress relaxation ovens and boxes

Elastocon offers cell ovens specially designed for stress relaxation tests of rubber. This means that the inner height of the cells are adapted to fit our relaxation rigs to achieve as good thermal contact as possible with the bottom of the cell.

The oven also has an intergrated draught hood that eliminates the changes in the force during the test due to temperature changes in the environment around the top part of the rigs. The hood is made of polycarbonate, and has a temperature control system (Peltier cooling system) capable of keeping the temperature within ± 0,25 °C.

We can also offer two types of temperature boxes, for room temperature and below.

Creep testers

Creep testing of polymers

Creep is the tendency of a solid material to move slowly or deform permanently under the influence of persistent mechanical stresses. It can occur as a result of long-term exposure to high levels of stress that are still below the yield strength of the material. Creep is more severe in materials that are subjected to heat for long periods and generally increases as they near their melting point.

Elastocon offers two types of test equipment for creep testing of polymers – an automatic relaxation and creep tester, EB 18-II-3, and the EB 24 film creep tester.