Vibration Characteristic Analysis Of Rotor Blades With Acoustic Resonance Condition Inside The Compressor

The rotor blade is one of the key components in the aero engine.Because of the large number of thin-structure rotor blades working in harsh and complex environment,so the failure rate of the rotor blades is one of the highest by using and testing of the engine.To solve the fatigue failure of the rotor blades,theory analysis and numerical simulation are employed to obtained the dynamic response of rotor blade combined with the acoustic resonance phenomenon.Firstly,according to the coupled vibro-acoustic theory the coupled FEM/BEM governing equation is obtained.Based on the basic theory of the coupled FEM/BEM,dynamic analysis of tablet structure can be taken,and then the solving equations expression under modal coordinates is obtained.Secondly,a finite element model for the study of thin-walled plate structure is set up.the simulation of the thin-panel structure for traveling wave loading is taken under random acoustic excitation based on the FEM/BEM method.Changing the excitation direction of the acoustic loading with vertical,45° from vertical,horizontal tip and horizontal transverse,it was applied with tone acoustic excitation and broadband random acoustic excitation on the thin-panel.Through simulation,the results of the vibration frequency response of the thin-panel are obtained.It is focus on the relations between the direction of acoustic excitations with the vibration response of the thin-panel on the first two bands of resonance frequency.Finally,the freedom vibration simulation of rotor blade is obtained only subjected to the acoustic examination,According to the mechanism of the multi-physics coupling for the aerodynamics-structure-acoustics,acoustic resonance condition is simplified.Through unidirectional fluid-structure interaction calculation,the rotor blade will been subjected to the steady aerodynamic loads.And then the freedom vibration response results of the rotor blade can be obtained with both the steady aerodynamic loads and acoustic excitation.Comparative analysis for vibration characteristics of random acoustic excitation is taken between before and after applying the aerodynamic loads.In the paper,the study for vibration characteristics of thin-panel structures subjected to acoustic excitation and rotor blades under acoustic resonance condition has certain engineering reference value.