Interval analysis of rotor dynamic response with uncertain parameters

The support stiffness, connecting structure stiffness and the phase and amount of rotor unbalance which affect rotor dynamic response significantly are “uncertain but bounded” parameters, in another word, the distributions of these parameters are unknown, but the intervals of uncertain parameters are always got easier.An interval analysis method, which solves the dynamic response with these uncertain parameters, has been presented. First of all, an interval perturbation analysis method is introduced to calculate the interval critical speeds. Then, based on interval mathematics and modal superposition method, the interval analysis method simplifies the uncertain parameters to interval vector so that it can get the intervals within which the dynamic response varies when less information of structure is known. The interval analysis method is efficient under the condition that probability approach cannot work because of small samples and sparse statistics characteristics. Finally, a numerical example of comparison between the interval analysis method and the Monte Carlo method is given, and the results illustrate the interval analysis method.