A component mode synthesis method for 3-D finite element models of aero-engines

Abstract

Because of the complicated configuration of aero-engines, 3-D finite element models are convenient and accurate to to simulate the vibration performance of the aero-engines, and are now widely used with a high order of Degrees of freedom (DOFs). A Component mode synthesis (CMS) method is introduced to reduce the computational effort of rotors and stator modeled by 3-D finite element. By additional master DOFs in substructures it’s more convenient than traditional CMS to get the inner response of substructures without mode expansion and is validated as being as accurate as traditional CMS. Rotating substructure of rotors with variable spinning speed can also be reduced by the method. Reduced gyroscopic matrix depended by variable spinning speed can be easily obtained by multiplying a speed coefficient to unit condensed gyroscopic matrix. A reduction example of an aero-engine model including casing model, bearings and counter-rotating rotors shows the accuracy and efficiency of the method. The method greatly decreases RAM and solution time used for dynamic analysis, which brings possibilities of a great number of repeatability analyses.