CONDITION MONITORING AND FAULT DIAGNOSIS IN ROTATING MACHINERY USING MODAL TEST & FINITE ELEMENT ANALYSIS

Abstract

Rotor dynamics is the study of vibration behavior in axially symmetric rotating structures. Devices such as engines, motors, disc drives and turbines all develop characteristic inertia effects that can be analyzed to improve the design and decrease the possibility of failure. At higher speeds, the inertia effects of the rotating parts must be represented in order to predict the rotor behavior. Excess vibration can cause noise and wear in structure. It is important to identify all the critical speeds within the range of operation and analyse the damping effects, mass unbalance and other phenomena also their effects in the safe operation. The experimental technique used thus far is called Modal Testing, a well known and widely used technique in research and industry to obtain the Modal and Dynamic response properties of structures. The technique has recently been applied to rotating structures and some research papers been published, however the full implementation of Modal Testing in active structures and the implications are not fully understood and are therefore in need of much further and more in depth investigations. The raw data obtained from experiment was used in finite element (FE) model for comparison. Since it has good capability for Eigen analysis and also good graphical facility, and obtained good result.3-D models result large number of nodes and elements. This paper demonstrates how to extract a plane 2-D model from the 3-D model that can be used with fewer nodes and elements because of ease of use, accuracy and performance. The aims is to establish a system identification methodology using the analytical/computational techniques and update the model using experimental techniques already established for passive structures but to active rotating structures, which subsequently help to carry out health monitoring as well as further design and development in rotating machinery.