Experimentelle und numerische Untersuchungen zur Schwingfestigkeit an Schweißdetails in Stahlrohrtürmen für Windenergieanlagen

At low-wind locations, economic operation of wind turbines is usually only possible with large rotor diameters and hub heights. Large hub heights present great challenges to the ultimate and fatigue limit state of the towers, which must meet certain static and dynamic requirements for the safe operation of the turbine. For material-efficient tubular steel tower structures, higher requirements are therefore necessary for the fatigue strength of welded notch details. This article deals with investigations to evaluate the fatigue strength of a typical design detail, the weld bushing. In addition, alternative concepts with the aim of increasing the fatigue strength are presented and evaluated, which on the one hand focus on the reduction of heat input and on the other hand on the surface layer hardening. In addition to experimental investigations on the influence of plate thickness and mean stress, the newly published standard DIN 18088-3 [1] will be used to examine the possibilities of a practical application of numerically based verification concepts for fatigue strength and compare them with the test results.