Fluid-solid Interaction Vibration Analysis Of Aircraft Fuel Pipeline Weld Macro-scale Modeling

The branch pipeline in the aircraft fuel pipeline system plays an important role in connecting the fuel pump.It is mainly manufactured by welding.Under the current welding technology,the mechanical properties of the weld area are lower than the mechanical properties of the base metal.The three-way structure of the welded fuel pipeline makes the study of fluid-solid interaction vibration characteristics more complicated.Therefore,it is of great engineering value to study the macro-scale modeling method of welds and analyze the fluid-solid interaction vibration characteristics of welded fuel pipelines for the design and manufacturing process improvement of aircraft fuel pipelines.The main research contents of this paper are as follows:(1)Acquisition of performance parameters of each area of aircraft fuel pipeline weld.The yield strength,tensile strength,Young ’s modulus and Poisson ’s ratio of weld zone,heat affected zone and base metal were obtained by micro tensile and ultrasonic echo experiments.The density of each zone was measured.The distribution of weld zone,heat affected zone and base metal was obtained by metallographic examination,which provided data support for macro scale modeling of weld.(2)The macro-scale modeling method of fuel pipeline weld structure and the finite element model of welded fuel pipeline for fluid-solid interaction analysis are studied.The model is divided into a separate entity of weld zone,heat affected zone and base metal,and the corresponding physical parameters and mechanical properties parameters of weld zone,heat affected zone and base metal are given.The finite element model and related simulation settings of welded fuel pipeline are established.(3)The fluid-solid interaction vibration characteristics of aircraft welding fuel pipeline are studied.The free modal analysis of the pipeline model with and without weld structure is carried out,and the constraint modal analysis of the pipeline model with and without weld structure and with and without fluid-solid interaction is carried out to verify the influence of weld structure and fluid-solid interaction on the natural frequency of fuel pipeline.The effects of fluid pressure and pipeline wall thickness on the vibration characteristics of the pipeline are studied,and the dynamic analysis method of the fuel pipeline under durable vibration load and high value vibration load is studied.(4)The test verifies the accuracy of the macroscopic scale modeling method and simulation model of the fuel pipeline weld.The free modal and constrained modal tests were carried out by using the test piece,and the natural frequency values were measured.Compared with the results of finite element analysis,the accuracy of the finite element model using the weld macro-scale modeling method was verified.