Response Study Of Blade Vibration And Tip Rubbing

The aero-engine, as the core equipment of the aircraft, is known as the"Pearl of the human industry crown". Because of this, improving the efficiency,safety and reliability of aircraft engines has an important strategic significance on the national economic development, scientific and technological progress and national security. According to the report from the world’s largest insurance company Allianz Insurance, the blade failure accounted for 42% of the gas turbine fault, of which 18.5% caused by blade fatigue failure and 23% caused by blade rubbing. It can be seen that the blade failure is a prominent problem restricting the development of aero-engine technology. The main achievements and contributions are as follows:1 . This thesis studied the effect of a rotor whirl orbit on the accuracy of non-intrsive stress measurement for a turbo fan. Based on this, the thesis proposed an extraction algorithm of vibration displacement when considering the effect of rotor whirl on expected time of arrival. This algorithm can effectively improve the accuracy of non-intrusive stress measurement.2. This thesis simulated the transient dynamic response of blade-coating rubbing by using LS-DYNA explicit-implicit analysis. Compared the different blade dynamic responses when blade rubbing with three kinds of coatings.3. Based on the large deformation theory and the finite difference discrete solution method, the blade response mode with the large deflection deformation was studied. This thesis obtained the bend moment distribution, curvature distribution and instantaneous shapes by elastic-plastic analysis. The results showed that the completely large deformation response process of the blade was composed with four stages.4. This thesis also studied the dynamic stress inversion method based on the vibration measurement of blade tip timing. Combined the displacement data measured by BTT method with the finite element simulation analysis, this thesis established the relationship between the vibration displacement and the vibration stress. Then, a new method of deducing dynamic stress of the whole blade was proposed.This paper studied the blade vibration and rubbing response by means of finite element simulation, numerical analysis and experimental research. For blade vibration research, this thesis deduced the data extraction method to improve the accuracy of blade vibration measurement. In addition, this thesis put forward the blade dynamic stress inversion method. For blade rubbing research, this thesis explored the transient dynamic process of blade-coating rub-impact and studied the response mechanism of large deformation of rub-impact blades. The researches in this paper provided both theoretical basis and scientific support for the online health monitoring of blades and the optimization design of blade-casing structure, which is helpful to improve the efficiency of aviation engine and improve the safety and reliability.