Research On Fault Of Hydraulic Pipeline Crack Based On Vibration Signal

The hydraulic pipeline is an important part of the aircraft hydraulic system,which plays a role in distributing and transmitting hydraulic energy.When the hydraulic pipeline is under the coupling vibration effect such as flow pulsating body flutter,it is easy to cause the pipeline damage and crack,and then cause the pipeline leakage fault,which will lead to flight accidents in serious casesDue to the widespread distribution of hydraulic pipelines on aircraft,it is difficult to quickly determine pipeline leakage faults,which seriously affects maintenance progress.Therefore,it is of great practical significance to carry out research on hydraulic pipeline crack failures.In this paper,the development of cracked pipelines and fault diagnosis methods are studied.The main tasks are as follows:Firstly,the dynamic model of crack pipeline was constructed to analyze the crack fault characteristics of hydraulic pipeline,and the equivalent model of crack pipeline was established.Considering the vibration balance equation of the pipeline under crack fault,the fluid-solid coupling model of aircraft hydraulic pipeline was established.On this basis,the frequency response of fluid-solid coupling vibration is analyzed.Secondly,the fluid-solid coupling vibration finite element analysis of the second crack pipeline takes the hydraulic pipeline of the Boeing 737 wing as the research object,carries out the three-dimensional model construction of the pipeline,simulates the crack degree with different diameter holes,analyzes the influence of different crack degrees on the vibration characteristics of the pipeline,and obtains the change rule of the natural frequency of the pipeline on the crack degree.Thirdly,research on crack fault diagnosis method based on improved neural network.Aiming at the pipeline fault characteristics,the particle swarm optimization algorithm was used to optimize the neural network,a hydraulic pipeline crack fault diagnosis model was established,and the model was analyzed and verified by MATLAB.Based on this,a hydraulic pipeline crack fault diagnosis simulation platform was established.Fourthly,experimental research on pipeline fault diagnosis.Set up an experimental platform for analyzing pipeline crack fault characteristics,formulate experimental procedures based on vibration theory,conduct experimental research on curved wing pipelines,and verify the correctness of crack fault diagnosis method by analyzing the experimental results.