Research On Vibration Characteristics Of The Blade Disc With Dry Friction Damper Under Quasi-periodic Excitation

Platform damper is a kind of effective method to deal with a blade vibration problem caused by excitation force. Energy absorption by dry friction damping between the damper and the blade can play a role in reducing vibration amplitude and attribute to effective vibration stress reduction. Dry friction damping with good damping effect, effective working margin width, able to work under harsh conditions, etc. now has been widely used in the aero-engine rotor blades for the purpose of vibration reduction. Research from multiple perspectives on dry friction damping characteristics and its influence on the vibration characteristics of the blade has a particularly important theoretical significance and practical value in engineering.The main work of the paper is as follows:(1) Query the relevant documentation, choose a kind of quasi-periodic excitation as an oscillation. The blade finite element model is constructed, and based on which a time domain calculation program is developed. Then the frequency response curves of the corresponding numerical examples are obtained and the laws are summarized.(2) Establish a practical engineering structure finite element model of blade disc sector, and each blade on which is coupled by stiffness unit and damping unit. The corresponding equivalent coefficients are obtained by linearization method. The vibration characteristics of two states which have uneven quality of platform damper and blade are studied respectively and the damping characteristics are concluded.(3) Establish the dry friction theoretical model in the contact interface of a called “ Cottage Roof ” damper. The constitutive expressions about dry friction and displacement and hysteresis loops with different roof angle are obtained. The equivalent stiffness and equivalent viscous damping formula are derived by using energy method and the first-order harmonic balance method, thereby establishing the macro-micro slip model of this type of damper.(4) Design and manufacture the “ Cottage Roof ” damper with different roof angle and thickness. Do experiments to verify the validity of this type of damper sheet through the comparison between the experimental results and the simulation results. Develop the numerical calculation program, by which to investigate the dry friction damping characteristics about roof angle, damper sheet thickness, dry friction coefficient and different type of quasi-periodic excitation.