Method for operating a machine plant having a shaft train

A method for operating a machine plant having a shaft train, comprising the steps of:

• a) computationally determining the natural frequency of at least one torsional oscillation mode of the shaft train and computationally determining the mechanical stresses of the shaft train occurring during an oscillation period of the torsional oscillation mode;
• b) determining in each case a correlation for each torsional oscillation mode between a first stress amplitude, which occurs at a position of the shaft train that is susceptible to the formation of stress damage, and a second stress amplitude, which occurs at a measuring location of the shaft train, on the basis of the stresses computationally determined for the respective torsional oscillation mode;
• c) establishing a maximum first stress amplitude for the position;
• d) determining a maximum second stress amplitude, corresponding to the maximum first stress amplitude, for the measuring location on the basis of the correlation;
• e) measuring the stress of the shaft train while the shaft train is rotating at the measuring location in a time-dependent manner;
• f) determining a stress amplitude at each natural frequency from the measured stress;
• g) emitting a signal in the event that, at one of the natural frequencies, the stress amplitude determined from the measured stresses reaches the maximum second stress amplitude.