An enhanced hybrid component mode synthesis procedure for rotor dynamic analysis of turbo-fan engines

摘要

In the present work, hybrid component mode synthesis (CMS) using both fixed-fixed and fixed-free interfaces with inertia relief attachment modes has been developed for rotor-dynamic analysis incorporating the gyroscopic effects of both shaft and disc. This CMS combines the advantages of the fixed interface method, known popularly as the Craig-Bampton method and the free-interface method, known as the Craig-Chang approach. It is shown in this paper that the present CMS predicts the whirl frequencies as accurately as predicted by Craig-Bamptom method and at the same time predict the forced responses as accurately as the Craig-Chang technique. The present hybrid CMS procedure has been validated using two rotor-bearing systems: (i) a rotor-bearing system comprising three discs mounted on to the flexible shafts of varying cross sections supported by two rolling element bearings with squeeze film dampers (sfd); (ii) a typical twin-spool rotor bearing configuration of turbo-fan engine. This technique is also capable for nonlinear rotor dynamic analysis.