Research On Sealing Performance Of Flareless Pipe Joint In Aircraft Hydraulic System

The hydraulic system provides power for the aircraft operating system,and pipeline is the main carrier of oil transportation in the hydraulic system.Under the complex environment such as fluid pressure pulsation and body vibration,the leakage failure rate of pipeline joints remains high,and there are serious potential safety hazards.Therefore,it is very important to carry out research into the contact mechanics and sealing performance of pipe joints.The thesis takes the non-flared pipe joint as the research object,conducts contact mechanics analysis of the joint assembly process of pipe joints,studies the sealing characteristics of the pipe joint under fluid pressure pulsation,and provides support for improving the sealing performance of the pipe joint.The main research contents and work of the thesis are as follows:(1)Establishment of the finite element model of the flareless pipe joint.Analyze the joint assembly process,the sealing contact mechanism and the factors influencing the sealing performance of non-flaring pipe joints.Modeling the joint assembly of a flangeless pipe joint based on contact theory.(2)Finite element simulation of tube extrusion without flare.Analyze the extrusion forming process of non-flaring conduit,study the forming quality of non-flaring conduit under different bulging pressures,use Abaqus to simulate the extrusion forming process of nonflaring conduit,and analyze the extrusion process under different bulging pressures.The deformation of the catheter and the contact stress distribution between the catheter and the sleeve can be used to obtain the appropriate bulging pressure.(3)Finite element simulation of the tightening assembly process of the flareless pipe joint.Analyze the process of tightening and assembling of non-flare pipe joints,study the effect of tightening torque on the sealing of pipe joints,use Abaqus to simulate the tightening and assembly process of non-flare pipe joints,and analyze the distribution of stress and the width of the sealing surface under different tightening torques and the change of contact stress,select the appropriate tightening torque.(4)Analysis of the influence of pump output pressure and pressure pulsation amplitude on the sealing performance of pipe joints.Analyze the output pressure and pressure pulsation characteristics of the aircraft hydraulic pump,establish the fluid-structure coupling model of the pipe joint,simulate the influence of fluid pressure and pressure pulsation amplitude on the contact surface width and contact stress distribution,and analyze the sealing performance of the pipe joint.