Charmec Phd project MU37 PhD Student: Björn Andersson Supervisors: Prof. Magnus Ekh, Prof. Johan Ahlström, Prof. Lennart Josefson Rail and wheel materials are subjected to very high stresses and, in some cases, also to elevated temperatures. The rolling contact loading results in a multiaxial stress state with a combination of compression and shear. The properties of the steel microstructure in rails and wheels are affected by elevated temperatures. If the temperature in the steel is increased sufficiently and followed by rapid cooling, then austenite and martensite might develop which can be detrimental for the steel. Earlier research within Charmec has been devoted to models for these phase transformations. However, there is a need to further develop the modeling e.g. regarding the coupling between the phase transformations and the temperature dependent cyclic mechanical behavior of the phases in the material. A purpose is to increase the quality in the simulations of residual stresses after the phase transformations and how the stresses are affected by repeated mechanical contact loading. Project MU37 will be run in co operation with a parallel experimental project (MU36) and will use test results to formulate and verify/validate simulation models. The developed models will be used to address applications such as short heating events (e g, braking situations) and welding and grinding of rails. CHARMEC researchers have previously studied thermal processes, both connected to rail welding and thermal damage induced by contact friction heating. Project MU37 will build on previous works, and the outcome will lead to accurate and predictive methods supporting technology development and decreasing overall life cycle cost.