Natural frequency analysis of a dual rotor system with model uncertainty

Although extensive studies have been carried out in numerical analysis of vibration characteristics of structures of rotor systems with model uncertainties and parameter uncertainties, one of the main issues which needs attention is representing the uncertainties at some specific elements of the structures. For a dual rotor system with both model and parameter uncertainties, the Riccati whole transfer matrix considering model uncertainties is derived by using the method of nonparametric stochastic modeling combined with the Riccati whole transfer matrix method, which can perform the model uncertainties at specific elements of a dual rotor system, and the nonparametric stochastic dynamic model is established. The effects of two types of uncertainties on the critical speeds of this system are studied, and the results are compared with related references. The results indicate that the effects of the two uncertainties on the first three-order critical speeds n_c1, n_c2 and n_c3 of this dual rotor system are different under the same uncertainty level. The research can provide a reference for the study of vibration characteristics of dual or multi-rotor systems with model uncertainties and parameter uncertainties.