A novel corrosion detection method using wavelet transformed mode shapes of a functionally graded rotor-bearing system

Abstract

"Development of online fault detection based on vibration characteristics of a rotating system has been the subject of interest for the last few decades. A novel corrosion detection method is suggested in the present work, based on the wavelet transformed modal analysis of a functionally graded (FG) rotor system. Material properties of an FG shaft are position and temperature dependant and graded in a radial direction following the power-law and nonlinear temperature distribution (NLTD) respectively. An FG rotor consisting of a mixture of Zirconium Dioxide (ZrO2) and Stainless Steel (SS) is considered, where the volume fraction of metal decreases toward the outer radius and ceramic volume fraction increases. The finite element (FE) formulations have been developed using Timoshenko beam theory (TBT) for modal analysis of a corroded FG rotor bearing system. A spatial variation of a wavelet transform is used to transform the computed FG rotor mode shapes into the wavelet domain to identify and locate the local corrosion defect. A sensitivity analysis and a parametric study has been carried out to further verify the validity of the suggested novel method."