Abstract:The aim of this paper is to study the stress status of the bolt fastener in coupling under complex loadings, the research result is greatly beneficial for the analysis of the failure of the screw bolt in coupling. The threads in the bolt and nut are modeled with accurately construct helical thread geometry and implanted into the ANSYS software. Research shows that the model has the ability to simulate the preload of bolt, equivalent stress of coupling under load, and structure stress of the screw bolt in coupling. The finite element results agree with the experimental observations quantitatively. 〖JP3〗In addition, the fatigue strength and the self relaxation of the screw bolt are more sensitive to the torsional load, which can provide reference for further research on the failure of screw bolt.