Analysis of a steam turbine rotor thrust collar fracture: root causes and repair
Year: 2026
Type: article
Abstract: Fracture of the turbine rotor thrust collar is a very rare failure. However, such a failure can occur due to some serious malfunction in the operation of the turbine. In this paper, the root cause of the rotor thrust collar fracture, which occurred in the history of a 35 MW steam turbine, is analyzed. The analysis was carried out based on the facts found and using numerical simulations in the Ansys software package. The cause of the fracture was determined to be high-cycle fatigue as a result of cyclic loading and a significant notch effect at the root of the shaft-collar transition radius. Cyclic loading was a consequence of the non-uniform loading of the collar over the surface, which was the result of incorrect sliding of the front bearing housing during the thermal expansion of the turbine casing in the start-up phase. The turbine rotor was repaired so that the cracked thrust collar was removed by machining, and the new collar was shrink fitted onto the rotor shaft. After the repair and the final assembly, the turbine was put into operation without any observed deficiencies.
Source: Procedia Structural Integrity
Authors: Marko Katinić, Pejo Konjatić
Institution: University of Slavonski Brod
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7160056483