Torsional and compressive properties of bolted joint under forward-reverse tightening

Obtaining the stress evolution law of bolted joint during the assembly process is of great significance for tightening process design and improving assembly performance. In this study, the bolt tightening analytical model is used to obtain the deformation coordination mechanism. Then, the evolution law of the stress during assembly process are obtained by FEA model, and the influence of different assembly parameters on the stress change is analyzed. Finally, the bolt tightening experiment is carried out, which verified the theoretical hypothesis and the FEA model. The results show that: in addition to the tensile normal stress, the thread torque also generates torsional shear stress that causes the torsional deformation of the screw during the tightening process. The torsional shear stress can be reduced by forward-reverse tightening process. Meanwhile, the utilization rate of bolted joint can be improved. This can increase the assembly design margin and improve the assembly performance.