The document summarizes a summer internship project analyzing the rotor dynamics of the Kikuchi rotor using different methods. The Kikuchi rotor, originally analyzed in 1970, consists of a steel overhanging shaft supported by bearings and separated into three disk locations of equal mass. Approximation methods calculated the lower and upper natural frequency bounds as 41.1Hz and 42.6Hz. Commercial software XLRotor modeled the rotor and determined the first three natural frequencies as 39.09Hz, 137.63Hz, and 305.84Hz. An in-house Cyient tool developed by Pratt & Whitney also analyzed the rotor and calculated the natural frequencies within 0.1% of the test data values of 42.52
IRJET- Rotor Dynamic Analysis of Driving Shaft of Dry Screw Vacuum Pump
Presentation1
1. ROTOR DYNAMIC ASSESSMENT OF KIKUCHI ROTOR
SUMMER INTERNSHIP PROJECT
BACHELOR OF TECHNOLOGY
Aerospace Engineering
SUBMITTED BY
Megha Tangri
R290212020
Under the Supervision of
Mr Chandrasekhar N
Project Lead
Mr Mahesh Nuka
Senior Project Manager
17th June-29th July, 2015.
2. Introduction
• The Engine Dynamics and Loads Team, Pratt & Whitney
Division is currently working on developing the design and
generating results of rotor dynamic analysis of Next
Generation Jet Engines using Cyient Tool.
• This SIP was meant to assess a rotor, also analyzed by Katuoso
Kikuchi in 1970 (hence the name) to calculate its first three
natural frequencies.
3. KIKUCHI ROTOR
• Katsuaki Kikuchi did a research on analyzing the
unbalance vibration of rotating shaft system with many
bearings and disks
• Paper published in JSME, 1970.
• Following are the figures-
7. KIKUCHI ROTOR
• ABOUT
- Supported by bearings separated by a distance of 800𝑚𝑚
- Type of overhanging shaft
- Steel; total mass 51.8kg
8. KIKUCHI ROTOR
• ASSUMPTIONS
- Neglect the overhangs
- Simply Supported
-The mass of the shaft has been assumed to be lumped in equal
proportion at the three disk locations. So each disk location
carries a total of 17.27 𝑘𝑔 where the rotating mass is 13.47 𝑘𝑔.
11. APPROXIMATION METHODS
• The lower bound and upper bound natural frequencies of the
Kikuchi Rotor were found using - Dunkerely Method and
Rayleigh Method respectively.
Method Natural frequency (Hz)
Dunkerely Lower Bound 41.1
Rayleigh Upper Bound 42.6
12. XLRotor
• Commercial Tool
• A product of Rotating Machinery Analysis, Inc. (RMA)
• Helps engineers model and analyze rotating equipment
quickly, efficiently, and reliably.
13. Shaft Input Sheet was opened and the shaft properties
were defined
The Bearing Sheet (named as ‘Brg’) was opened and the
stations at which the bearings are located and their
stiffness was input
Geometric plot was viewed and verified from the
Geometric Plot Sheet
Command was given to update the station as well as the
beam files in order to generate the respective Updation
Files
XLRotor was run to find out the roots for Undamped
Critical Speed
XLRotor
17. CYIENT TOOL
• Developed by and copyright of P&W
• Used for Rotor dynamic Analysis of real time rotors
• Highly efficient
18. CYIENT TOOL
Geometric Plot is created by using UNIX
Graphics Software
Plot is imported to the Cyient Tool
Nodes are made and masses are added
accordingly at the desired locations
Errors(if any) are checked and rectified
Software is run to generate results
19. RESULTS
Natural Frequency 𝝎 𝟏 𝝎 𝟐 𝝎 𝟑
Test Data* 42.52 168.83 358.62
XL Rotor 39.09 137.63 305.84
CYIENT TOOL, as highly accurate as it is, gave only ~0.1%.
20. CONCLUSION
• The rotor dynamic assessment of Kikuchi Rotor was done
through three methods- Approximate Analysis, XLRotor and
through the Cyient Tool.
• The results showed that Cyient Tool gave the most accurate
results for the first three critical velocities.
21. REFERENCES
• 1. “Features”. XL Rotor. Web. 19 June. 2015.
• 2. Tiwari, Rajiv. “Theory and Practice of Rotor dynamics”. Document posted in
Indian Institute of Technology, Guwahati NPTEL online classroom. Web.
• 3. Kikuchi, K. Analysis of unbalance vibration of rotating shaft system with many
bearings and disks. Bull. JSME. Vol. 13, No. 61. 1970. Page 864.
• 4. Rao, J.S. Rotor Dynamics. 3rd ed. New Delhi: New Age International(P) Limited,
1996. Print.
• 5. Vance, John M. Rotordynamics of Turbomachinery. United States of America:
John Wiley & Sons, Inc., 1988. Print.
• 6. Ziaei-Rad, S and R. Tikani. “Rotordynamics”. Document posted in Mechanical
Engineering Department, Isfahan University of Technology, Iran. Web.
• 7. Rao, Singiresu S. Vibrations of Continuous Systems. New Jersey: John Wiley &
Sons, Inc., 2007. Google E-Books. Web.
• 8. Yoon, S. Y., et al. Control of Surge in Centrifugal Compressors by Active
Magnetic Bearings. Advances in Industrial Control. London:Springer-Verlag,
2013. Web.
