Dynamic characteristics of flexible shrouded blades in aero-engines

The effect of impact and friction between shrouded blades in aero-engines under rotational speed is investigated to analyze the influence of parameters of shrouded blade system on dynamic characteristics of the system. To investigate the impact and friction, a model composed of springs and a cantilever beam carrying a mass is developed to simulate the cyclic symmetry structure of the shrouded blade in aero-engines. The model is placed into a centrifugal force field caused by a high rotational speed, and the centrifugal force is taken into account. The Euler-Bernoulli beam theory is employed to get the equation of motion by considering the centrifugal forces, the gas excitation forces and the combined effect of the impact and friction between shrouds. Based on the equation of motion, parametric analysis is performed to study the effect of the contact angle, the gas excitation force, the friction coefficient, the stiffness and the gap between shrouds on the steady-state responses of the system. Numerical results and their analysis show preliminarily that the parameters have effects on the dynamic characteristics of the system. The results of the analysis are meaningful to the design of the shrouds and the control of the vibrations.