Study on Loosening Load Law and Performance of Double Nut of Transmission Tower

Based on the bolt connection characteristics of transmission tower, this paper studies the loosening mechanism and causes of double nuts of transmission lines.The finite element simulation analysis of bolt connection is carried out by using ABAQUS software.The influence of innitial pretightening force and transverse vibration amplitude on the axial pretightening force of bolt joints and the slip of thread meshing surface is studied.Reducing the initial pretightening force and increasing the transverse vibration amplitude will accelerate the attenuation of axial pretightening force and increase the slip of thread meshing surface.Taking the common nut as the research object, the lateral vibration test of the fastener was completed, and the change trend curve of the axial pretightening force of the bolt was obtained.The anti-loosening performance of equal-thickness double nuts was better than that of other nuts.Aiming at the anti-loosening defects of the existing double nuts, the design of the integrated self-locking double nut is proposed and the lateral vibration test is carried out.The anti-loosening performance index of the integrated self-locking double nut is significantly improved, and the anti-loosening stability is greatly enhanced.