Frequency Domain Characteristic Analysis Of Fluid-Structure Interaction Vibration Of Civil Aircraft Fuel Pipeline

As an important part of the aircraft fuel system,the fuel pipeline is the only channel for conveying fuel.When working,the fluid-structure interaction occurs between the fluid in the pipeline and the wall structure,which seriously affects the safety and reliability of the pipeline.This paper focuses on the fluid-structure interaction vibration mechanism of civil aircraft fuel pipeline,and carries out the research work of fluid-structure interaction dynamic model construction,frequency domain solution and clamp constraint mechanism,and analyzes its frequency domain characteristics.The research results are of great significance to accurately reveal the vibration characteristics of civil aircraft fuel pipeline and improve the safety and reliability of pipeline.The main research work and contents are as follows:(1)Based on the beam model,combined with the structural characteristics of thin wall and large diameter of fuel pipeline,the friction term is added to establish the fluid-structure interaction vibration 14-equation model of straight and curved fuel pipeline,and the frequency domain solution method of transfer matrix is deduced.Furthermore,the expressions of complex boundary constraint matrix and external load excitation vector are constructed,which lays a theoretical foundation for subsequent research.(2)The equivalent model of fuel pipeline clamp constraint is constructed,and its equivalent stiffness coefficient is obtained by finite element technology,and its point transfer matrix model is established.Taking the typical fuel pipeline as the research object,the dynamic models of fuel straight pipeline and bending pipeline under the elastic constraint of clamp are constructed,and the numerical simulation and modal experiment of the inherent characteristics of pipeline vibration are carried out.(3)Based on the dynamic model and frequency domain solution of the fuel pipeline and clamp constraint,the influence of wall thickness and fluid density on the inherent vibration characteristics of typical fuel straight pipeline and bending pipeline is analyzed.Further,the fuel straight pipeline is selected as the research object,and the influence of fluid flow on the frequency domain characteristics of pipeline vibration is analyzed combined with the airworthiness pressure load.(4)The fluid-structure interaction vibration test bench of the fuel pipeline was built,and the fluid-structure interaction modal experiment and fluid-structure interaction vibration experiment of the fuel pipeline under different wall thicknesses and flow rates were carried out.The fluid-structure interaction frequency domain response results of the pipeline were obtained correctness of theoretical analysis method and results was verified by comparing the numerical simulation results.