Using an aero-engine rotor tester with casing

a finite element model of engine to simulate the actual mounting condition was built. The modal tests of the tester under installation were carried out

and the finite element model was updated and verified based on the modal test results. The first 3 order natural frequencies and modal shapes of the tester were calculated under the conditions of the free boundary

fixed boundary and flexible mounting boundary with different mount stiffness values. By defining a rotor-stator coupling factor

the effect of the mount stiffness on the coupling degree between the stator and the rotor was studied. Results show that the coupling degree between stator and rotor increases with the increasing effect of mounting condition for a certain order mode. Moreover

the effect of the mount stiffness values on the rotor-stator coupling is nonlinear. Because the coupling phenomena between stator and rotor exist in many modes of practical large scale turbofan engines

the effect of the mount stiffness values on the coupling vibration of engine cannot be ignored. Therefore

the mount conditions should be considered carefully in finite element modeling and simulating.