The Vibration Characteristic Analysis Of Blade System Considering Additional Damping Of Tenon Root

Engine blade has the characteristics of quantity,harsh load condition,and complex work environment because of it works as the moving parts with high speed rotation.The tenon of engine blade structure is prone to produce fatigue then greatly affect flight safety under coupling loadings of mechanical,pneumatic,thermal field and rotation inertia force field.It has became two considerable damping vibration modes of blade that utilizing friction between tenon of blade and root or adding viscoelastic material to tenon of blade.It has obtained the preliminary application in engineering for the purpose of effectively vibration reduction.However,lesser corresponding theoretical study,This article adopts FE and analytical method based on beam model to study the vibration characteristics of blade system under tenon friction and viscoelastic material respectively.Including the following four parts in detail.First of all,a dovetail mortise structure as the research object to study the characteristics of contact friction by ANSYS,modeling for the tenon of blade system with friction,analyzing intrinsic property and response under basement excitation of the vibration system.Then obtaining mode of vibration and frequency response figure of the system.It turned out that friction has slight influence on the intrinsic property and response under basement excitation of the vibration system slightly dropped.And then,based on the above,viscoelastic damping block is added on the blade root,for finite element modeling.Aslo it is compared with tenon of blade system without viscoelastic damping block and analyses its influence on intinsic property and response under basement excitation.The results show that its intinsic property significantly reduced and response under basement excitation lower while compared with blade tenon system considering friction.Moreover,creating dynamics model of blade system considering tenon friction of contact by equivalent beam method,gaving the method to tackle the inherent intinsic property and response.It proves to be rational that the close result compared with the finite element.Furthermore,considering influence of parameters of friction(contact stiffness,contact damping,and friction coefficient.etc)on dynamics of the system.Results indicate that the contact stiffness should be small and contact damping be large if by friction vibration damping.Finally,three cases of dynamic analysis model of blade system are established by the equivalent beam method,including only added viscoelastic damping on blade root,considering the friction and adding viscoelastic damping blocks,damping block and damping bar under basement excitation.Using the above method to solve the inherent features and basic motivation of the response,through case study,solve and compare intinsic property and response results with finite element by example.At the same time,analysis parameters of viscoelastic damping block(bar)(thickness,energy storage modulus and loss factor)influence on dynamics of the system.Results demonstrate that increasing the thickness of damping block,storage modulus,loss factor is favorable to blade vibration.This paper can provide reference for the dynamic characteristics and vibration mechanism of tenon of blade of aero-engine or further study on the damping reduction design of tenon of blade.Eventually provide support for the application of anti-vibration and fatigue life of blade.