Promotion Melchior Deutscher

On 21.11.2022, Dipl.-Ing. Melchior Deutscher successfully defended his scientific thesis within the framework of the doctoral procedure with the topic "Consideration of temperature fields in fatigue tests on UHPC". In addition to the chairman of the doctoral committee, Prof. Dr. Peer Haller (Technische Universität Dresden), Prof. Dr.-Ing. E.h. Manfred Curbach (Technische Universität Dresden), Prof. Dr. Harald Garrecht (University of Stuttgart) and Dr. Silke Scheerer (Technische Universität Dresden) were present as reviewers. Dean Prof. Dr. Jürgen Stamm (Technische Universität Dresden) was also present as another member of the doctoral committee.

Increasingly powerful materials enable more efficient structures. Through the development of increasingly stronger concretes, it is possible, for example, to build higher and more filigree structures. Here, the load due to alternating stress can increase proportionally compared to that due to the dead weight. Consequently, knowledge of the fatigue resistance becomes increasingly important. This resistance is determined in idealised laboratory tests carried out at the highest possible frequency. At higher frequencies, various researchers have found that the test specimens heat up. This raised the question of how this heating influences the test results.

Melchior Deutscher addressed this topic in his dissertation "Consideration of temperature fields in fatigue tests on UHPC". In a very extensive parameter study, he examined different concretes under varying test boundary conditions such as changing frequencies, stress collectives or specimen geometries. In evaluating the tests, the focus was on the simultaneous processes of load-induced heating and the release of this heat to the ambient air as well as the temperature-dependent change in reference strength and applied stress clearance.

Mr Deutscher summarised the identified effects and mechanisms in a method that can be used to eliminate the influence of the increased temperature on the basis of measured values of the ambient temperature and the heating on the sample surface in the follow-up to cyclic tests with sample heating. This means that it will also be possible in the future to carry out cyclic tests in a time-saving manner, i.e. with increased test frequency. The proposal thus differs fundamentally from methods for eliminating the influence of temperature that have already been proposed by other researchers.

The dissertation was written as part of the DFG project "Influence of load-induced temperature fields on the fatigue behaviour of UHPC under pressure swell loading" (project number 353981739) as a sub-project in the Priority Programme 2020 "Cyclic damage processes in high-performance concretes in the Experimental Virtual Lab".

We warmly congratulate Mr Melchior Deutscher on completing his doctorate and wish him all the best and much success for his future career.