Lu Y.,Xi'an University of Technology |
Zhang Y.,Xi'an University of Technology |
Shi X.,Building Machinery Co. |
Wang W.,Xi'an Jiaotong University |
And 2 more authors.
Nonlinear Dynamics | Year: 2012
Based on the nonlinear theory, the unbalanced responses of a fixed-tilting-pad gas-lubricated journal bearing-rigid rotor system are investigated. A time-dependent mathematical model is established to describe the pressure distribution of gas-lubricated journal bearing with nonlinearity. The rigid rotor supported by a fixed-tilting-pad self-acting gas-lubricated journal bearing is modeled. The differential transformation method has been employed to solve the timedependent gas-lubricated Reynolds equation, and the dynamic motion equation has been solved by the direct integral method. The unbalanced responses of the rotor system supported by fixed-tilting-pad gaslubricated journal bearings are analyzed by the orbit diagram, Poincaré map, time series, and spectrum diagram. The numerical results reveal periodic, period-3, and quasiperiodic motions of nonlinear behaviors of the system. Finally, the effects of pivot ratio and preload coefficient on the nonlinear dynamic characteristics of the fixed-tilting-pad self-acting gaslubricated journal bearing-rotor system are investigated. © Springer Science+Business Media B.V. 2011.
Deng Y.,Building Machinery Co. |
Zhou X.,Building Machinery Co. |
Qi B.,Jiangsu Subiao Electrical Furnace Co. |
Li X.,Hefei University of Technology |
And 2 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2015
Mechanical properties, microstructure and corrosion resistance of 42CrMo steel pin after QPQ treatment were compared with these of the chromium plating one through conventional mechanical property testing, metallurgical microstructure analysis and neutral salt spray testing. The results show that the comprehensive properties of the QPQ treated pin are better than these of the chromium plating one. Surface microstructure of the QPQ treatment pin is composed of dispersed nitride and tempered sorbite, and the center microstructure is tempered sorbite, while the surface microstructure of chromium plating one is tempered martensite, and the center is tempered sorbite. Compared with the chromium plating process, QPQ treatment can form a dense and uniform protective layer on the surface of pin with better corrosion resistance. In summary, the QPQ treatment can replace chromium plating process to be used in surface protective treatment of pin. ©, 2015, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.