HMK Gold Medal awarded to Jørgen Kjoshagen Trømborg
Jørgen Kjoshagen Trømborg received HMK Gold Medal for his PhD thesis in the course of UiO’s Årsfest September 2nd, 2016. The King’s Gold Medal is awarded to outstanding young researchers once a year.
Jørgen Kjoshagen Trømborg received HMK Gold Medal at UiO’s Årsfest 2016. (Photo: Privat)
Jørgen Kjoshagen Trømborg defended his PhD thesis in 2015 on a dissertation on "Modelling the onset of frictional sliding: Rupture fronts, slow slip, and time-dependent junction laws ". The dissertation has resulted in six articles in top international journals, including one article in the Proceedings of the National Academy of Sciences.
Trømborg's work has focused on developing a better understanding of friction. Friction is an old subject, and the basic law of friction is well known: Friction counteracts motion. For something to start sliding, the forces that restrict the motion must be surpassed. Modern experiments and theory provide new insights into what happens during the initiation of relative motion between two surfaces in contact. Real surfaces are not smooth, but rough if examined closely enough. If two surfaces are pressed together, only a small fraction of the surfaces will be in real contact. These microscopic contacts must be broken before the two surfaces can slide relative to each other. During the last ten years, experimental advances have made it possible to film such ruptures.
Jørgen Kjoshagen Trømborg developed a simulation model and performed computer simulations of such ruptures. By combining established methods for how forces propagate through materials with insights from recent experiments, he developed a simple model that explains the interactions between the microscopic contacts. Trømborg's model is the first to explain the experimental observations from the last ten years. The model shows that the classic model for friction between two materials must be updated and replaced by a new model that also includes information about how the two surfaces come to rest relative to each other - a history-dependent friction law. Trømborg's model will therefore provide the basis for many new discoveries and applications within the area of friction over the next years.
The work has been performed as part of an international collaboration that aims to develop new ways to assemble and combine materials to reduce friction and wear.