Modal Parameters For Cracked Rotors: Models And Comparisons

Abstract

Two mathematical models for the study of modal parameters of cracked rotors are presented in this paper. The first model follows a Rayleigh-Ritz approach and the second is based on a finite element strategy. Both models can handle rotating rotors with variable cross-sections, carrying any number of disks, supported on several bearings and having one or more cracks along its length. To validate the above-mentioned models, an exact analytical solution was developed for an idealized rotating rotor with no disks, supported on two bearings and having one crack. This is referred to as the reference case. The paper reports typical results in dimensionless form as obtained from the two models and these are compared with the reference case. Two modal indices were used for presenting the results. One of the indices is proposed and used for the first time by the authors. Recommendations for future work are included in this paper.