1 Department of Mechanical Engineering, Technical University of Denmark2 Solid Mechanics, Department of Mechanical Engineering, Technical University of Denmark
A 2D plane strain finite element program has been developed to investigate very high cycle fatigue in wind turbine roller bearings due to rolling contact. Focus is on fatigue in the inner ring, where the effect of residual stresses and hardness variation along the depth is accounted for. Both classic Hertzian and elastohydrodynamic lubrication theories have been used to model the pressure distribution acting on the inner raceway and results are compared according to the Dang Van multiaxial fatigue criterion. The contact on the bearing raceway is simulated by substituting the roller with the equivalent contact pressure distribution. The material used for the simulations is taken to be an AISI 52100 bearing steel and linear elastic behavior is here assumed. The effect of different residual stress distributions is also studied, as well as the effect of variable hardness along the depth, relating its values to the fatigue limit parameters for the material. It is found that both for Hertzian and elastohydrodynamic lubrication contacts, the Dang Van criterion predicts that fatigue failure will first occur in the subsurface region and that, regardless of the specific pressure distribution used, the hardness distribution can have a significant influence on the safety against failure for bearings subjected to very high cycle fatigue loading.
Institution of Mechanical Engineers. Proceedings. Part C: Journal of Mechanical Engineering Science, 2014, Vol 228, Issue 12, p. 2079-2089