High-resolution active thermography

• Subject Area: Condensed Matter Physics
• Term: Funded in 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 572258861

We intend to set up an active thermography measuring station. This should be suitable for standard measurements at the level of the current state of the art and be used directly in research and teaching in three departments of the university, as well as enabling the development of new thermographic measurement methods and evaluation procedures that are not yet available on the market. The active heating of a test object induces a heat flow. This can be measured in both transmission and reflection with time resolution. The heat input is achieved by different excitations, punctual or planar, e.g. by halogen lamps or laser excitation, inductive or by ultrasonic input. Layers or flaws inside the sample reflect the heat flow. A high-precision camera records inhomogeneities of the heat flow on the surface of the test object in a time-resolved manner. This makes it possible to detect material defects with three-dimensional spatial resolution. With an active thermography setup, a large number of BHT research questions in the field of materials science can be answered using non-destructive imaging. For example, the heat flow in components and materials can be used to detect defects, flaws, fractures, corrosion or blowholes. Hidden delaminations can be made visible and coating thicknesses can be measured. In addition, thermal stress analyses can be carried out in metals under tension or the thermal conductivity of polymer systems can be determined. Such an imaging measurement method is therefore an excellent addition to the possibilities of material investigations that are already provided by existing measuring instruments (e.g. X-ray CT, SEM). Questions of ongoing research activities at the BHT are the non-destructive testing of the joining quality of new composite materials made of wood, bamboo and GFRP materials. Another focus is the non-destructive characterization of metallic, polymeric and ceramic 3D printed components. In addition, we intend to further develop the method of active thermography algorithmically and experimentally. We plan to develop a thermo-tomography method for analyzing thermal properties, especially the heat transfer coefficients of critical component-internal interfaces and structures. Further development of data processing is also planned, particularly in the analysis of 2D and 3D images (material phase segmentation with the aid of neural networks, quantitative evaluation of material inclusions, layer thicknesses or pore structures, but also correlations of (volume) images with data from other measurement methods (e.g. CT). The possibility of carrying out active thermographic measurements directly at the university is therefore very much welcomed by colleagues.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Hochauflösende Aktive Thermographie
• Instrumentation Group: 8620 Strahlungsthermometer, Pyrometer, Thermosonden
• Applicant Institution: Berliner Hochschule für Technik (BHT)
• Leader: Professorin Dr. Astrid Haibel