Dynamics Analysis Of Bladed Disk Rotor System

In this paper, different aspects of the bladed disks rotor system of the engine is studied through theory analysis and finite element simulation. The research on the motion of lumped-parameter mistuned bladed disks, the optimize sequencing of blades when the detuning is given, the dynamic characteristic of the continuous parameter blades-disk-axle rotor system and the solution of the Fluid-Structure Interaction(FSI) in blades, is carried out, respectively. And, the finite element simulation of cracked blades is preliminarily explored.First, based on the lumped-parameter mistuned bladed disks model, the general rule of the effects of detuning parameter on the modal and the response of the bladed disks system is obtained by discussing its vibration characteristic including the modal and the forced vibration response. The results achieved are used to solve the problem of the modal and the localization of vibration caused by detuning. And then, the vibration characteristic of the bladed disks system with nonlinear friction dampers and its damping effect comparing with the undamped system are also analyzed through the introduction of the platform damping block shock absorber into the bladed disks rotor system.On the other hand, the optimization research on the selection of the best sequence of given detuning blades is carried out in two kinds of condition, with nonlinear friction dampers and without friction damping, by using two intelligent optimization algorithms named DPSO and TAEA respectively during installing. It aims to balance the whole vibration energy of system among blades to reduce the fatigue and prolong the life, in the consideration of decreasing the amplitude and averaging the vibration of blades.Second, as the rotor speed continues increasing, the vibration problem on rotor caused by blades-disk-axle coupling is increasingly prominent. Dynamic differential equations are established for blades-disk-axle rotor system by using modal synthesis method. The relationship among natural characteristics of different continuous parameter bladed disks rotor systems and its changes due to the increasing order are researched, according to the obtained natural frequencies and modes of three rotor systems including rigid disk-flexible shaft rotor system, elastic disk-flexible shaft rotor system and elastic blades-elastic disk-flexible shaft rotor system.Meanwhile, since FSI becomes one of the research hotspots and difficulties in many areas, the problem of FSI of blades in airflow for long periods of time is more and more prominent. Due to the inconsistent meshing on flow field and solid field, the nodes in the interface do not match. To solve this problem, the blades is subjected to the surface temperature treatment and surface pressure treatment by using two different data fitting methods including response surface approximation and Kriging interpolation. And then, the best fitting method for this problem is obtained through contrastive analysis of fitting precision.Third, defects and cracks in bladed disk is inevitable because of the defect existed in the metallurgical process and the macroscopic cracks generated while processing and being used (such as loading, fatigue and stress corrosion). The cracked bladed disk rotor is analyzed by finite element method, and the influence of different cracks is obtained through exploring the variation of fracture parameters stress intensity factor.