Vibration Characteristics And Vibration Control Of Aviation Hydraulic Pipeline Based On Hard Coating

As an important system connecting the plunger type hydraulic pμmp and actuator,aviation hydraulic pipeline system is an important electromechanical system to realize the rudder surface operation and landing gear retracting and dropping functions of aircraft.With the rapid development of aviation industry,the aviation industry in China in a variety of airplane hydraulic system with lightweight and pressure increase,the hydraulic pipeline system often occurs due to excessive vibration damage,for the plane made a great impact the safety and reliability,aviation hydraulic piping system vibration problem is the engineering problems to be solved.Aviation hydraulic the vibration of pipeline system is very complex,which due to aircraft engine double rotor unbalance harmonic vibration excitation can lead to larger forced vibration,the current for aviation hydraulic piping system vibration control study is not yet perfect,hard coating as emerging damping materials applied in aviation hydraulic piping system research has yet to mature.Therefore,it is of great scientific significance and engineering application value to study the vibration control of hard coating for aviation hydraulic pipeline system.In this paper,the vibration response of aviation hydraulic pipeline is modeled,finite element analysis and experimental research are carried out.According to the vibration damping performance of the hard coating,three different powder materials were optimized to prepare the hard coating on the pipeline matrix through Oerlikon Metco 9MC atmospheric plasma spraying equipment.Combining with the actual working state of aircraft and taking the straight pipe in the aviation hydraulic pipeline system as the research object,the composite structure model of hard-coated aviation hydraulic straight pipe was established,namely,the static equilibriμm differential equation of hard-coated aviation hydraulic straight pipe was derived based on the elastic thin shell theory.Based on Hookean’s law,shell non-extrusion hypothesis,Kirchhoff-Love hypothesis and Love shell theory,the constitutive equation of hard-coated aviation hydraulic straight pipe was deduced.Based on The Hamiltonian energy principle,the characteristic equation which can be used to solve the inherent characteristics of hard-coated aviation hydraulic straight pipe thin shell model is derived.The model building and modal analysis of aerial hydraulic straight pipe（uncoated）are carried out by finite element method.The model creation and modal analysis of aviation hydraulic straight pipe with hard coating were carried out.By comparing the finite element simulation results of aviation hydraulic pipe with or without hard coating,the variation rules of natural frequency and main mode of vibration of aviation hydraulic pipe under multiple parameters are obtained.It is found that with the increase of the thickness of the hard coating,the offset of the natural frequency of the model increases and the displacement of the main mode decreases.Different coating materials and pipe materials for hard coating aviation hydraulic type straight tube natural frequency and the main vibration displacement,the influence of different level of YSZ ceramic coating（8%Y₂O₃-Zr O₂yttria stabilized zirconia）damping effect is better than the other two kinds of materials,6061 t6 alμminμm alloy coating hard coating substrate material damping effect is better than the other two kinds of substrate materials.The vibration response of the high and low pressure rotor under constant frequency harmonic excitation and the vibration response under frequency sweep excitation are analyzed by combining the test and simulation.The error between the amplitude of the test and the simulation vibration response is within 20%,which proves the accuracy of the model.Through orthogonal experiment design to hard coating aviation hydraulic straight pipe under high and low pressure rotor fixed frequency simple harmonic excitation vibration response and frequency sweep excitation vibration response analysis,found the coating thickness,pipe material and hard coating material,pipe material and hard coating material effect on the vibration response amplitude is higher than the influence of coating thickness;The optimal solution of orthogonal test is 6061T6 alμminμm alloy aviation hydraulic straight pipe coated with 300μm thickness ceramic YSZ（8%Y₂O₃-Zr O₂yttriμm stabilized zirconia）.It is determined that the rigid coating can meet the requirements of vibration control in practical engineering,and provides a reference for vibration analysis and vibration control design of aviation hydraulic pipeline system.