A numerical material model can only be as good as the data determined in material and component tests. The most important test for ULTRASIM® data determination is the high-speed tensile test.
High-speed Tensile Tests – Test Specimen in Focus
High-speed Tensile Test: Optical Strain Measurement
The test specimens produced from an injection-molded sheet are first given an irregular screen before being clamped in the high-speed tensile machine. The actual tensile test is filmed using a high-speed camera. The whole of the local distortion field on the sample can be determined by finishing with image processing software. Together with the recorded force, the stress-strain relations relevant for material modeling can be derived, the parameters of the ULTRASIM® material model tailored to this (parameter fit).
The tests are carried out for various orientations of the samples at various temperatures, ambient conditions and strain rates in a number appropriate for statistical purposes.
High-speed Tensile Test: Material Measurements and Data Flow
Both the control and subsequent evaluation of the machine and film data are carried out using software tools specially developed at BASF for this purpose, ensuring that ULTRASIM® material modeling can accurately represent all the properties relevant for plastics such as dependence on strain rate, tension-compression asymmetry and failure.