Abstract: The locking mechanism of threaded connection is analyzed and calculation models of the threaded connection tightening torque and loosening torque are established which are modified when applied to prevailing torque fasteners.The calculation reliability of the modified models are testified through experiments.Factors which may have effects on the anti-loosening performance of threaded fasteners including the initial clamping force, friction coefficient, screw length between bolts and nuts and locking methods are studied in this paper.Effects of the above-mentioned factors on the anti-loosening performance are verified through the transverse vibration test.The study results can provide guidance for the reasonable use of fasteners for locking.

Key words: anti-loosening performance, calculation model, prevailing torque, initial clamping force, friction coefficient