本研究以有限元素法來分析含複合材料轉軸與油膜軸承於轉子系統的動態行為。系統由轉軸、轉盤與油膜軸承所構成。轉軸是由複合材料所組成且模擬為Timoshenko樑，即考慮轉軸之旋轉慣性及剪應變效應，轉盤假設為剛體，並考慮質量偏心及陀螺效應，軸承以油膜軸承來模擬。本文分別探討轉軸疊層方式、軸承使用不同黏度的潤滑油對系統共振頻率與側向穩態響應的影響。由數值結果顯示，隨著軸承的黏度逐漸增加，因系統轉速改變而造成軸承擁有不同勁度係數與阻尼係數的影響會逐漸降低。隨著軸承黏度增加，在軸承位置之共振幅度減小，而在非軸承位置之節點，共振幅度隨著軸承黏度增加。

Dynamic behavior of a rotor system with composite shafts and oil-film bearing is analyzed by the finite element method in this thesis. Rotating shafts of the system are composed of composite material and modeled as Timoshenko beams, which include the effects of rotary inertia and shear deformation. Disk is considered to be rigid with its mass eccentricity and gyroscopic effect taken into account. Bearings are oil-film bearings. Effects of stacking sequence of rotating shaft and viscosity of bearing lubricant on resonance frequencies and steady-state responses of the system are investigated. Numerical results of this research show that, whirl speed curves of rotor system have some irregular changes due to the speed-dependent stiffness and damping coefficients of oil-film bearings, and as the viscosity of bearing lubricant increases, the irregular its decreases. As the viscosity of bearing lubricant increases, the resonance response of the system at bearing location decreases, and the resonance response of the system at other locations increases.

[1] Ruhl, R. L., and Booker, J. F., “A Finite Element Model for Distributed Parameter Turbo-rotor System,” ASME, Journal of Engineering for Industry, Vol. 94, pp. 126-132, 1972.
[2] Nelson, H. D., and McVaugh, J. M., “The Dynamics of Rotor-Bearing Systems Using Finite Elements,” ASME, Journal of Engineering for Industry, Vol. 98, pp. 593-600, 1976.
[3] Nelson, H. D., “A Finite Rotating Shaft Element Using Timoshenko Beam Theory,” ASME, Journal of Mechanical Design, Vol. 102, pp. 793-803, 1980.
[4] Dym, C. L., and Shames, I. H., Solid Mechanics–A Variational Approach, McGraw-Hill, New York, 1973.
[5] Eshleman, R. L., and Eubanks, R. A., “On the Critical Speeds of a Continuous Rotor,” ASME, Journal of Engineering for Industry, Vol. 91, pp. 1180-1188, 1969.
[6] DuBois, O. B., and Ocvirk, F. W., “Analytical Derivation and Evaluation of Short Bearing Approximation for Full Journal Bearing,” NACA Report 1157, 1953.
[7] Lund, J. W., and Saibel, E., “Oil Whirl Orbits of a Rotor in Sleeve Bearing,” ASME, Journal of Engineering for Industry, Vol. 89, pp. 813-823, 1967.
[8] Lin, Y. H., and Lin, S. C., “Optimal Weight Design of Rotor Systems with Oil-Film Bearings Subjected to Frequency Constraints,” Finite Elements in Analysis and Design, Vol. 37, pp. 777-798, 2001.
[9] Zinberg, H., and Symonds, M. F., “The Devleopment of an Advanced Composite Tail Rotor Drivershaft,” 26th Annual National Forum of American Helicopter Society, pp. 1-14, 1970.
[10] Dos Reis, H. L. M., Goldman, R. B. and Verstrate, P. H., “Thin-Walled Laminated Composite Cylindrical-Tubes: 3. Citical Speed Analysis,” Journal of Composites Technology and Research, Vol. 9, pp. 58-62, 1987.
[11] Bert, C. W., “The Effect of Bending-Twisting Coupling on the Critical Speed of a Driveshaft,” Proceeding, 6th Japan-U.S Conference on Composites Materials, Orlando, pp. 29-36, 1993.
[12] Bert, C. W., and Kim, C. D., “Whirling of Composite-Material Driveshaft Including Bending-Twisting Coupling and Transverse Shear Deformation,” Journal of Vibration and Acoustics, Vol. 117, pp. 17-21, 1995.
[13] Singh, S. P., and Gupta, K., “Composite Shaft Rotordynamic Analysis Using a Layerwise Theory,” Journal of Sound and Vibration, Vol. 191, pp. 739-756, 1996.
[14] Chang, M. Y., Chan, J. K., and Chang, C. Y., “A Simple Spinning Laminated Composite Shaft Model,” International Journal of Solid and Structures, Vol. 41, pp. 637-662, 2004.
[15] 阮競揚, 含橫向裂縫的轉子軸承系統之動態特性分析, 國立成功大學航空太空工程研究所碩士論文, 1997.
[16] 黃忠立, 轉子-軸承系統在多臨界轉速限制下之輕量化設計, 國立成功大學航空太空工程研究所碩士論文, 1987.
[17] Gibson, R. F., Principles of Composite Material Mechanics, CRC Press, 2014.
[18] Dharmarajan, S., and McCutchen Jr., H., “Shear Coefficients for Orthotropic Beams,” Journal of Composite Materials, Vol. 7, pp. 530-535, 1973.
[19] Boukhalfa, A., and Hadjoui, A., “Free Vibration Analysis of an Embarked Rotating Composite Shaft Using the Hp-Version of the FEM,” Latin American Journal of Solids and Structures, Vol. 7, pp. 105-141, 2010.
[20] Lee, C. W., Vibration Analysis of Rotor, Kluwer Academic Publishing, 1993.