Investigation of dynamical characteristic of shrouded blade of aero-engine subjected to impact and friction

The effect of combination of impact and friction on the dynamic characteristics of shrouded blade of aero-engine is investigated in this paper. Adding shroud to blade of aero-engine is an effective method of vibration reduction for blade subjected to centrifugal forces and gas forces which can lead to high cyclic fatigue (HCF). Approximate mass-springs model for shrouded blade is developed so as to predict vibration amplitudes and to study nonlinear characteristics. The dynamical equations of a shrouded blade system can be derived and solved to get numerical results. Parameters such as ratio of stiffness, friction coefficient and contact angle of shrouded blade are detailed. Nonlinear characteristics for the combination of impact and friction are also studied through bifurcation diagram with non-dimensional rotating speed and amplitude of gas excitation force as parameters. Numerical results indicate that the dynamical characteristics of the shrouded blade are varied with the parameters of the shrouds. Based on the numerical study, some practical suggestions for choosing parameters of shrouded blade are made.