Testing Methods

In the event that no suitable testing methods exist for a customer's specific question, the HTL develops new methods. The application range, requirements for measuring range, resolution, and measurement uncertainty, as well as other boundary conditions, are coordinated with the customer. The HTL then creates a testing concept, which may require the use of finite element simulations for design. Commercially available components are used as much as possible, and existing standards are taken into account. The testing concept is coordinated with the customer, followed by the construction and procurement of individual components, assembly, software development, verification, and documentation.

The HTL develops special software for evaluating measurement data. For example, measurement data from imaging systems such as computed tomography, scanning electron microscopy, and laser scanning microscopy are analyzed in relation to user-defined characteristic features, and subsets of this data are extracted. These can then be simulated in finite element models. It is applied for the quantitative evaluation of microstructural features such as surface roughness, internal pores, or homogeneity in relation to the strength and reliability of corresponding components.

Another focus is the development of high-temperature measurement methods for large components or test volumes. For example, the bending strength of transport rollers for roller furnaces with a length of 2 m can be measured at temperatures up to 1200°C at the HTL. Special sample holders enable efficient high-temperature strength testing of up to 7 standard samples in a single heating process. Computed tomograms can be recorded at temperatures up to 2000°C using special ovens. Many of the high-temperature measurement methods have been implemented in so-called thermo-optical measurement systems (TOM). Special measurement methods are also developed for testing external oven systems.

As a combination of mechanical and non-destructive testing technology, in-situ CT measurements can be performed. Samples are loaded on bending, tension, or compression and multiple CT measurements are performed during loading. This makes it possible to detect material damage within the sample for the respective load and to track it visually until complete failure.