Analysis of the Response of a Multi-Rotor-Bearing System Containing a Transverse Crack in a Rotor

The paper describes work that has been carried out into the flexural vibrational behavior of a rotor mounted on several bearings and containing a transverse crack. A method of solving the equations of motion of a general system is presented. This method utilizes standard rotor dynamics computer programs and enables calculations on large systems to be made on a routine basis. An approximate method of estimating the reduction of a section diameter required to model a crack for use in beam theory based on finite elements is given which is simple to use and gives acceptable results in practice. The application of the methods to some large turbogenerators is described.