Research On The Characteristic Of Dynamic Response Of Rotating Dovetail Interface Blades With Fitting Parameters

Rotating machinery such as aeroengine,turbine and gas turbines is a new generation of power plant after steam turbine and internal combustion engine.It not only reflects a country’s comprehensive strength,improves the energy structure of the protection of national defense and energy security,but also has important significance to achieve the sustainable development of environment.Because the aeroengine,turbine and gas turbines have to operate in a ectremely rugged environment for a long time,the strong design level and manufacturing capacity are must.The blade,as one of the most important and key parts of rotating machinery,has been in a high speed,heavy load,automation and complex work environment,resulting in a series of serious and complex problems.Because most fault of rotating machinery is caused by the blade and rotating machinery often plays an important or key role in large equipment,it will cause very serious harm once there is a fault or loss of stability.What’s more,it will also make a great loss of economic and sometimes even cause casualties or inestimable and irreplaceable damage to the society.The application of the dovetail interface blades in turbomachinery is very extensive.Because the blade is always subjected to complex loads,it is easy to produce more serious stress concentration in the dovetail structure which can cause breakdowns of the aeroengine.In this paper,the research of nonlinear inherent characteristics and vibration response characteristics on blade with dovetail attachment is studied.The main contents of this paper include:(1)Firstly,The three-dimensional entity model of the dovetail interface blades-disk system was established by finite element method.The validity of the modal was verified by straight dovetail interface contact surface pressure distribution and the slip level from reproduction of literature.Next,the effects of the structure parameters,fitting parameters and machining error mode on the dynamic characteristics of the blade were analyzed with the modal analysis.Finally,the structure parameters,fitting parameters and machining error mode on the vibration response of the blade were analyzed by the way of Harmonic response with pre-stress.(2)Secondly,The finite element method is used to establish the dynamic model of the dovetail interface blade,constraint Appling displacement boundary condition to the root of blade with bilinear hysteretic dry friction model.Next,the effects of the maximal slip level,excitation amplitude,friction damper stiffness mode on vibration response characteristics of the blade were analyzed with the modal analysis.The optimized bilinear hysteretic model is obtained by comparing the hysteresis loops and the vibration response of different dry friction models.Finally,the effects of excitation amplitude mode on vibration response characteristics of the blade were analyzed by using the optimized dry friction model.(3)Finally,The two-dimensional entity model of the dovetail interface blades-disk system was established by finite element method.The validity of the modal was verified by compared with inherent characteristics of the third chapter.Next,the effects of gap and friction of the dovetail attachment mode on nonlinear vibration response characteristics of the rotating blade were analyzed by using the finite element transient analysis method.Finally,the influence of assembly parameters on the vibration response of rotating blades was studied by changing the external excitation,friction coefficient and contact stiffness.