Simulation of tool wear and plasma-surface interaction

Tunnel boring machines wear out when used underground. In his dissertation, Dr Dennis Wingender used simulations to investigate what this wear looks like in detail and what could be done to prevent it. Dr Tobias Gergs also relied on simulations: however, the focus of his doctoral thesis was on the interactions between a plasma and the surface that limits it. These are of great importance for applications such as coatings. Both researchers were honoured for their outstanding work with this year's Gebrüder Eickhoff Prize. The prize was presented on 5 June 2024.

In mechanical tunnelling, cutting blades are used to excavate soft ground. They consist of a metallic body reinforced with welded metal matrix composite. ‘Microscopically, this material consists of hard carbides embedded in a softer metal matrix,’ explains Dennis Wingender. When excavating the ground, the tools wear out: fine cracks form, among other things. In his dissertation, Wingender developed a computationally efficient method for simulating the propagation of cracks at the microscopic level in order to investigate this type of wear and to improve the microstructure in response to it.

Plasma-surface interactions play a key role in most plasma applications, such as plasma-assisted catalysis or coating processes. ‘However, the time and length scales of plasma and surface differ by several orders of magnitude, thus preventing a uniform theoretical description,’ says Tobias Gergs. Plasma simulations are therefore supplemented by effective surface models, which, however, simplify or even neglect the fundamental atomic processes. A generalisation that retains atomic accuracy can be achieved through machine learning. In his dissertation, Gergs has devoted himself to the development and testing of appropriate methods.

The Gebrüder Eickhoff Prize not only stands for excellent research work, but also for the fruitful connection between the Bochum campus and companies with local roots. The Eickhoff company donated the prize in 1989 to mark its 125th anniversary and awards it annually for outstanding dissertations in the fields of mechanical engineering, electrical engineering and information technology.