Prevailing torque and residual prevailing torque of Bolt-Nut connections having slight pitch difference

Abstract

In this study, by applying three-dimensional FEM, the nut screwing process is analyzed to obtain the prevailing torque T_p confirming anti-loosening. Since the nut unscrewing properties after the nut tightening is more important to prevent the nut self-loosening, the nut unscrewing is also analyzed to obtain the residual prevailing torque T_p^u newly defined in this process. Both results of T_p and T_p^u are in good agreement with the experimental results. With increasing the pitch difference, the residual prevailing torque T_p^u increases as well as the prevailing torque T_p.

Keywords:

• Bolt-Nut connection
• pitch difference
• anti-loosening performance
• residual prevailing torque
• three dimensional FEM