Crack Detection on Rotary Elements Using Vibration Analysis

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Ari, Mostafa | 2012

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 42799 (08)
University: Sharif University of Technology
Department: Mechanical Engineering
Advisor(s): Sayyaddi, Hassan
Abstract:
Rotating machinery are found in most industrial units, that are highly susceptible to transverse cross sectional cracks due to fatigue. The vibration pattern of a rotor system reflects the mechanical parameter changes in the system. These vibrations can be used for identifying the cracks and appropriate actions can be taken to prevent more damage to the system. The dynamic behavior of cracked rotor is a subject of considerable current interest. Several researchers have developed models of cracked rotor systems. Therefore, In this thesis, the influence of the presence of transverse cracks in a simple Jeffcott rotor is analyzed. In first, on the basis of fracture mechanics, the direct and cross-coupled stiffnesses of a simple rotor with a breathing crack have been derived. Then, using the modeling and simulation of rotor on Abaqus the first three frequencies were derived. the crack detection method using changes in frequencis was formulated as an inverse problem which can be solved by optimization algorithms. The numerical simulations suggest that good predictions of shaft crack location and depth are possible and the proposed method is feasible.
Keywords:
Vibrational Analysis ; Breathing Crack ; Inverse Problem ; Optimum Scheme ; Jeffcott Rotor

No TOC