A developed component mode synthesis for parametric response analysis of large-scale asymmetric rotor

A generalized and efficient method is proposed in this paper for parametric response analysis of large-scale asymmetric rotor. If the bearings are anisotropic in asymmetric rotor, the motion of the rotor-bearing system will be governed by ordinary differential equations with periodically time-variant coefficients in both fixed and rotating frame. Response analysis of such parametric system can be attempted by assuming solution based on Hill’s method. If the number of degree of freedoms (DOFs) of the original model is N and the number of terms considered in the truncated assumed solution is m, for response analysis one has to solve a set of equations with (2m+1)N unknowns. Calculating this kind of equations requires a lot of computational costs, and the application of 3D finite element model will lead to greater computational costs. To avoid this costly approach, the fixed-interface component mode synthesis (CMS) is employed to form a reduced-order model (ROM). Although conventional CMS is adequate enough to make response analysis of largescale structures, an optimized scheme still needs to be developed for the response analysis of large-scale asymmetric rotor to achieve high efficiency and accuracy. The optimized scheme concerning a single substructure and multiple substructures are established respectively. Finally, the developed approach is validated through a simple model and a large-scale realistic two-pole generator rotor. And factors that influence the parametric response are investigated.