Nonlinear Dynamic Analysis of Shrouded Turbine Blade of Aero-engine Subjected to Combination Effect of Impact and Friction

The nonlinear dynamic analysis of shrouded turbine blade with combination effect of impact and friction between shrouds is presented in this paper. Adding shrouds to blade is for vibration reduction. It is very complex to analyze nonlinear dynamics in the presence of nonlinearities such as nonlinear resilience of springs and piecewise linearity. The shrouded blade is modeled as mass-spring model due to its features of cyclic symmetry; couplings of axial and tangential displacement of the shrouded blade are taken into account. The dynamic equations with nonlinear resilience of springs and piecewise linearity are numerically solved. Bifurcation diagrams, phase portraits and Poincare maps are employed to analyze the dynamic behavior of the shrouded blade system. The numerical results show that nonlinear shrouded blade system exhibits a variety and complex of dynamic behaviors that include periodic, multi-periodic, chaos motion, jump phenomena, etc. The nonlinear dynamic behavior of the system varies with the increase of the rotational speed, nonlinear factors of springs and amplitude of gas excitation force. The results can be helpful in understanding physically the nonlinear phenomena of a shrouded blade of aero-engine with multiple nonlinear factors, and the bifurcation results are practically meaningful for parametric design of shrouded blade.