Modeling of Multi-stepped Rotor-bearing Systems by the Continuous Segment Method

This work presents a new method here named Continuous Segment Method (CSM) for modeling complex rotor systems with multiple disks and bearings. It consists in dividing the domain of the system into subdomains, or segments, in order to solve the eigenvalue problem of the system. After solving the problem for each segment individually, continuity conditions are used to developed the eigenfunctions for the entire system. These functions, which also give the mode shapes, are then used to discretize the partial differential equations that model the system by means of modal analysis, leading to uncoupled first order differential equations for the modal coordinates. The method can be used to obtain close-form solutions of multi-stepped rotor systems with arbitrary number of steps, bearings and disks. The CSM is applicable for isotropic and homogeneous rotors with stepped cross-sections. The bearings are considered isotropic and can have either constant or speed dependent coefficients. The model of the shaft takes into account the rotary inertia, gyroscopic moment and shear deformation. Numerical examples show the effectiveness of the method in modeling rotor systems by comparing its results with the well known finite elements method for a simple and complex rotor system. (c) 2021 Elsevier Inc. All rights reserved.

Automated summary

This work introduces a new method called Continuous Segment Method (CSM) for modeling complex rotor systems with multiple disks and bearings. The method divides the system domain into subdomains, solves the eigenvalue problem for each segment, and uses continuity conditions to develop eigenfunctions for the entire system. CSM can obtain closed-form solutions for multi-stepped rotor systems and is applicable for isotropic and homogeneous bearings.