This article features with the enhancement of the static coefficient of friction by laser texturing the contact surfaces of tribological systems tested under dry friction conditions. The high-rate laser technology was applied for surface texturing at unprecedented processing rates, namely using powerful ultrashort pulses lasers in combination with ultrafast polygon-mirror based scan systems. The laser textured surfaces were analyzed by ion beam slope cutting and Raman measurements, showing a crystallographic disordering of the produced microscopic surface features. The laser induced self-organizing periodic surface structures as well as deterministic surface textures were tested regarding their tribological behavior. The highest static coefficient of friction was found of µ20 = 0.68 for a laser textured cross pattern that is 126% higher than for a fine grinded reference contact system. The line pattern was textured on a shaft-hub connection where the static coefficient of friction increased up to 75% that demonstrates the high potential of the technology for real-world applications.

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Rolling bearings are a part of every wind-turbine transmission. In terms of bearing design, the bearing rings are of particular interest. The current trend for increasing power and dynamic stress, together with the associated increases in specific loads, have brought creep-an irreversible relative motion between bearing rings and shafts or housings-to the forefront. Creep leads to wear and can cause shaft displacements with serious consequences for the meshing of teeth in gearboxes, for example. In fact, many insurance companies cite the creep of bearing rings as one of the main causes of wind-turbine gearbox failures.This article presents a complex kinematic 3D FE multi-body simulation of a rolling bearing. This simulation makes a detailed analysis of the relative motion or creep of bearing rings possible for the first time.It also presents options, based on materials technology and design, for reducing or eliminating creep in existing systems or at the product-development phase. The 2 key solutions, both based on an additional layer between bearing and housing, that show best results are presented within this article. This gives the user specific information for optimizing the bearing structure with respect to the choice of bearing and bearing ring design to ensure that future damage is prevented.