The pressure gauge pipeline at the pump outlet of China-Myanmar crude oil pipeline has sustained micro-vibration,high pressure and large temperature difference,which leads to frequent leakage of oil at the threaded joint,which seriously threatens the safety of the pipeline system.The mechanical characteristics of pipe threads with 1/2NPT specification were numerically calculated by finite element software,it was found that when the vibration frequency of the thread surface increased from 30 Hz to 150 Hz,the maximum Mises stress and the maximum shear stress decreased significantly,by 14.11％and 12.84％,respectively.The maximum Mises stress and maximum shear stress on the thread surface increased obviously when the internal pressure of the pipeline increased from 4 MPa to 12 MPa,which increased by 247.2％and 242.5％,respectively.The ambient temperature had little effect on the stress of thread.When the temperature increased from 10℃ to 80℃,the maximum Mises stress increased only 0.00019 MPa.Vibration was the main cause of pipe thread joint failure,and the vibration frequency of 135 Hz was the critical point of the rapid change of the force of the thread in the field,necessary vibration reduction measures should be taken to ensure the safety of the connection.
维普
万方数据