Fatigue Life Prediction of Rotor Slot-Dovetails in Pumped Storage Generator/Motor Considering Transient Loading

AbstractFor fatigue life prediction, the maximum stress calculated by the structural static analysis is used as load calculation in normal continuous operating conditions, which is not valid in time-varying performing situations. This article proposes a fatigue life prediction method considering repetitive time-varying and asymmetrical stresses as a stress spectrum for calculation loading to predict the accumulative fatigue life for the rotor slot-dovetails of the pumped storage generator/motor (PSGM) under multiple transient situations. The structural transient analysis is performed to calculate the time-varying stress caused by the centrifugal force. Then, the total stress is obtained by superimposing the centrifugal stress with the thermal stress caused by temperature difference, which is used as the loads for fatigue life calculations. Through fatigue life calculation in each condition, the numbers of cycles to failure and the initial sites of impending failures are determined. By the cumulative fatig...