Based on finite element (FE) method, a dynamic model of a dual-rotor-blade-casing coupling system is established. The bearings, bladed rotors, disks and casing are simulated using spring-damping element, beam element, shell element and beam element suitable for curved beam separately (the casing stiffness and damping using spring-damping element). The blade-casing rub-impact is simulated using point-point contact elements; here the corresponding nodes of the blades and the casing are identified as the contact points. These contact elements describe the coupling of the rotor and the casing by the augmented Lagrangian method. Complicated vibration responses of the coupled system are analyzed by time-domain waveform, amplitude spectrum and orbit.
