Studies on the Effect of Shaft Bow for a Multi Mass Flexible Rotor Model

The effect of initial shaft bow on the unbalance response of a rotor bearing system has been studied using a multi mass flexible rotor model. The equation of motor of the rotor-bearing model have been derived following finite element method and solved for unbalance response in presence of initial shaft bow using Runge-Kutta routine available in MATLAB. Typical unbalance response characteristics of bent shaft i.e self-balancing at certain speed, has been clearly brought out through the simulation results. Response phase angle has also been obtained from the simulation results. Experiments have been conducted up to the rotor speed of 5000 rpm, which is above the first critical speed, for validation of the simulation results partly. The initial shaft bow and unbalance level as provided in the experimental rig has been incorporated in the simulation model. There is good agreement between the experimental and simulation results