Research On Sealing Mechanism And Reliability Of Non-flaring Extrusion Pipe Joint Under Airworthy Load

Aviation hydraulic piping system is the power transmission path of the civil aircraft hydraulic energy system,and it is also called the "blood vessel" of the hydraulic energy system.Most of the leakage faults in the hydraulic energy system appear on the hydraulic pipe joints.The high-pressure sealing and reliability research of the pipe joints has an urgent need in the application research of civil aircraft parts.This article combines the airworthiness load of civil aircraft to carry out research on the sealing characteristics and reliability of aviation hydraulic pipe joints.The purpose is to provide support for improving the sealing technology of civil aircraft aviation hydraulic pipe joints and to study the changes in the performance of the joint sealing surface under airworthiness loads.The main research content and work of this thesis are as follows:(1)Establishing the sealing mechanics model of non-flaring extrusion pipe joints Taking the non-flaring extrusion pipe coupling sleeve-external thread end contact model as the research object,based on the Hertz contact theory and the Greenwood-Williamson rough contact model to establish a smooth The mechanical model of the sealing contact of the pipe joint under the surface and the rough surface,to study the change law of the contact pressure and contact area of the sealing contact surface.(2)Research on the sealing performance of non-flaring extrusion pipe joints under airworthy load.Taking the non-flaring extrusion pipe joints as the object,a simulation model is constructed and the airworthiness load characteristics are confirmed.Using ANSYS Workbench software to perform finite element analysis,obtain the sealing stress change law and natural frequency of the joint seal contact area,consider the fluid-solid coupling effect of hydraulic oil and liquid,compare and verify the effect of the gap fluid on the joint sealing state,and study aviation hydraulics under airworthy load The changing law of the sealing performance of pipe joints.(3)Experimental research on non-flaring extrusion pipe joints under airworthy loads.Build a pipe joint test bench with typical airworthy loads and data acquisition capabilities for aviation hydraulic systems,and write data acquisition programs.Taking the composite pipeline with non-flaring extrusion pipe joints as the research object,conduct modal,pressure and vibration tests to verify the correctness of the simulation analysis results and the working state under functional vibration loads.(4)Reliability analysis of non-flaring extrusion pipe joints.Taking non-flaring extrusion pipe joints as the research object,based on the reliability analysis theory and the Six Sigma reliability analysis module in the finite element software,the simulation analysis is carried out to study its Reliability under different material characteristic distributions and seaworthy load distributions,and sensitivity analysis is carried out.The research results of this thesis provide a reference for improving the sealing performance and reliability of extruded non-flared pipe joints,and are of great significance to the progress of domestic joint standards.