Study On Stress Analysis Method Of 3000 Psi Hydraulic Pipeline Of Civil Aircraft Based On Typical Airthiness Load

In recent years,China has made outstanding achievements in the independent research and development of civil aircraft,but the relevant technical standards and specifications mainly refer to foreign countries.There is a big gap between the achievements with independent intellectual property rights and foreign countries.In addition,the working load and mechanical characteristics of the hydraulic pipeline system of civil aircraft are extremely complex,and the reliability requirements are high.In this paper,combined with the airworthiness load of civil aircraft,the stress analysis and test research of hydraulic pipeline system are carried out,in order to provide support for the analysis and construction of hydraulic pipeline system with independent intellectual property rights.The main research contents and work of this paper are as follows:(1)Typical airworthiness load analysis and stress analysis flow design of civil aircraft hydraulic pipeline system.Based on the airworthiness standard of international transport air-craft,starting from the characteristics of typical airworthiness loads,this paper analyzes the superposition mechanism of pressure,displacement and vibration loads on the hydraulic pipeline system of different parts of civil aircraft,determines the load condition and stress analysis criteria of stress analysis,designs the stress analysis process of hydraulic pipeline system of civil aircraft,and studies the stress analysis method.(2)The establishment of finite element analysis method for hydraulic pipeline system of civil aircraft.Taking 3000 psi civil aircraft hydraulic pipeline system as the research object,based on the theory of finite element analysis,the methods of model simplification,bounda-ry condition setting and mesh generation are proposed.In addition,combined with the the-ory of fatigue damage,bandat and Dirlik mathematical models are used to predict the life of civil aircraft hydraulic pipeline system under high cycle fatigue load.At the same time,the transfer matrix method and the finite element method,which are widely used in the modal analysis of civil aircraft piping system,are given to lay the foundation for the solution of its natural frequency.(3)Stress analysis of hydraulic pipeline system of civil aircraft and influence of airworthiness load on the stress distribution and the natural frequency.Taking the ARJ21-700 wing area local hydraulic pipeline system as the research object,the finite element model is established in Abaqus software to solve the stress distribution,stress power spectral density diagram and natural frequency under different stress analysis load conditions.Finally,the airworthiness evalua-tion is completed by combining the fatigue life prediction method and stress analysis criteri-on.In addition,the control variable method is used to study the influence of typical air-worthiness load on the stress distribution and the natural frequency of hydraulic pipeline.(4)Test and verification of hydraulic pipeline of civil aircraft.Build a pipeline test-bed that can reproduce the pressure,displacement and vibration loads,and take two ARJ21-700 civil aircraft hydraulic pipelines as the research object,carry out the confirmatory tests under different stress analysis load conditions,and verify the correctness and feasibility of the stress analysis method of civil aircraft hydraulic pipeline system proposed above.In this paper,the stress analysis and experimental research methods of civil aircraft hydraulic pipeline system based on airworthiness provisions are expected to lay a theoretical foundation for the standard construction and optimization design of domestic civil aircraft hydraulic pipeline system.