In a tensile test (destructive material testing) according to DIN EN ISO 527-1, the force and change in length of a sample is measured as a function of the applied strain. The measurement can also be carried out under defined temperature (-35 to +250 °C). The tensile test is used to determine the modulus of elasticity, tensile strength and elongation at break of a material. Changes in these material properties after artificial ageing or exposure to media are also of interest.
In a bending test, the sample is quasi-statically stressed by pressure. In the 3-point bending test, the test specimen is positioned on 2 supports and loaded in the middle with a test stamp. Fields of application here are the determination of the bending modulus, the bending strength, etc.
In an impact test, the resistance of a material to an impacting (dynamic) load is determined. In the notched impact test, the workpiece is provided with a notch before the test, if necessary, whereby increased stress peaks occur at the notch. A pendulum hammer with a certain kinetic energy hits the back of the specimen and shatters it. This test can also be carried out at defined temperatures. Low temperatures increase the brittleness of the material (cold brittleness).
The compression set is an important parameter for elastomers that are used, for example, as seals. The test specimen is first compressed to a certain proportion of the thickness and fixed at constant compression set. This state is maintained for a defined time, whereby additional influencing variables, such as increased temperature, can act on the test specimen. After unloading, the remaining deformation is measured. If the remaining compression deformation is too high, the seal could be limited in its effectiveness.
In the tear propagation test, a defined defect is introduced into a test specimen, for example by means of a knife cut. The test specimen is then stressed at this point and the force is measured during the crack propagation. The measured force provides information about the crack resistance of the material. The test is usually carried out according to DIN ISO 34-1 on elastomers for seals and according to DIN EN ISO 8067 for foams.
Peel strength, i.e. the resistance of a flat material to peeling off, is of particular interest for films, non-wovens, carpets, upholstery fabrics and adhesive tapes. Depending on the application and test standard, the adhesive force can be peeled off at a peel angle of 180°, 90° or at a freely selectable angle. Similarly, roller devices can be used to maintain defined peel angles, for example in the roller peel test according to DIN EN 1372 with a 90° peel angle or in DIN EN 1464 with a peel angle of approx. 60°.