ROTOR DYNAMIC ANALYSIS USING TRANSFER MATRICES

Abstract

Rotor dynamic analysis is considered the most important part of the design of rotating machinery. A proper estimation of rotor-bearing system parameters leads to a safe and durable operation. Transfer Matrix models of rotor-bearing systems are widely used to perform the critical speeds, unbalance response, and stability analysis of rotating machinery. It is also capable of handling many complicated rotors with a relatively simple models and satisfacting results This thesis demonstrates the transfer matrix method with its types of models namely the Lumped and Continuous models. Critical speed analysis is performed using these models showing the difference in modeling procedure and results obtained. The difference in results is then explained using an order of magnitude analysis of the distinctive quantities impeded in transfer matrices of the continuous and lumped models. Also a new technique is introduced in the stability analysis to evaluate the complex frequencies of the rotor-bearing system using the continuous approach. A first step solution is performed using continuous rotor model with the application of Transfer Matrix Polynomial method to obtain preliminary values for complex frequencies. Which in turn are entered to the continuous scheme program as initial guesses to extract the continuous approach results. The unbalance response of rotors due to disk eccentricity is obtained without increasing the dimension of the transfer matrices. The presented method allows to investigate the case of more than one eccentric disk with phase shift in direction of eccentricity using a single rotor analysis.