VIBRATION BEHAVIOR OF THE ROTOR WITH TRANSVERE CRACK WITH SOME COMMENTS ON CRACK DETECTION | ||||
The International Conference on Applied Mechanics and Mechanical Engineering | ||||
Article 16, Volume 13, 13th International Conference on Applied Mechanics and Mechanical Engineering., May 2008, Page 12-22 PDF (336.51 K) | ||||
Document Type: Original Article | ||||
DOI: 10.21608/amme.2008.38990 | ||||
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Authors | ||||
METWALLY H. M.1; MORSI E.2; BADAWY M. H3 | ||||
1Professor of Mechanical Engineer, Alexandria University, Egypt. | ||||
2Assistant Professor of Mechanical Engineer, Alexandria University, Egypt. | ||||
3Mechanical engineer, Alexandria University, Egypt. | ||||
Abstract | ||||
ABSTRACT The present work deals with crack behavior, detection, analysis, determination and diagnosis of cracked rotors. Crack detection is very important for any rotating machine. It can save all the rotating parts like blades, impellers, fans and bearings. Crack behavior arises up non-linear differential equations that include the most influence of stiffness change. The nonlinear differential equations are solved by a computer program to calculate reduction in stiffness due to crack. The theoretical solution and calculations of stiffness reduction for rotor suspension systems was carried out. Programming software to predict the crack spectrum time wave form, run-up and costdown amplitude verse rotating speed, and the difference of natural frequency due to crack behavior unbalance amount, eccentricity and angles. The experimental work is helpful to assure the correctness of theoretical work, so constructing a test rig that simulates our problem has to be done. The experimental analysis is used to predict the cracked shaft and the change in crack stiffness. Run-up and cost down method is used for directly predicting the cracked shaft by monitoring the shift of frequency for critical speed. The conclusion of the results show that, crack affects the natural frequency of the shaft and its stiffness which in turn has an effect on all vibration characteristics. The theoretical results show sub-harmonics and harmonics of rotating shafts according to speed, how the crack affects the natural frequency and the great effect of changing the phase angle and how it can be used for correction the crack effects. | ||||
Keywords | ||||
Vibration; transverse cracked; detection | ||||
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