Calculation method of thread load distribution and finite element analysis

YAN Ting-liang, LI Jia-chun

(Department of Mechanical Engineering, Guizhou University, Guiyang 550025, China)

Abstract: Aiming at the theory that there is no system in the existing domestic thread design, the theoretical analysis method of the thread expansion method was proposed，and the thread expansion method was used to analysis the load proportion formula along the thread meshing line. The influence of bolt parameters on the thread bearing ratio was discussed. Through the ANSYS Workbench statics module, the finite element analysis of the thread secondary stress distribution during bolt tightening was carried out. The ratio distribution of the axial force of the nut was verified by the two analysis methods of SOPWITH and YAMAMOTO. The results were verified and compared, and the reliability of the nut expansion method was verified by the nut deformation test. The influence of Young's modulus ratio Es/Eb, pitch P, thread friction coefficient μ, internal and external thread profile on nut load distribution of threaded teeth was investigated by 3D finite element analysis.The results show that the bolt parameters Es/Eb、P/D and tooth form are the main parameters affecting the load distribution. For the external thread, the material with larger Young's modulus should be selected, and the internal thread should be made of material with smaller Young's modulus. It can reduce the uneven distribution of thread load.

Key words: threaded fastener; load distribution; ANSYS Workbench; finite element analysis