TRANSIENT ANALYSIS OF PLAIN AND TILT PAD JOURNAL BEARINGS INCLUDING FLUID FILM TEMPERATURE EFFECTS

The paper considers vibration response of spinning shafts supported by flexible fluid film bearings to sudden mass imbalance (blade loss). A time transient study of the plain journal bearing with thermal effect s is performed. A comparison between three transient analyses is perfo rmed. The three transient analyses studied are, the full nonlinear ana lysis, linear analysis using dynamic coefficients, and pseudo transien t analysis using static application of dynamic loads. The validity of the nonlinear transient analysis is checked by matching the lower unba lance results with the linear analysis and the static equilibrium posi tion results with Newton-Raphson iterative scheme. A nonlinear transie nt analysis of the tilt pad journal bearing is also performed, and a c omparison is drawn between the three approaches.