S1102-2-2 Predictive Method of Apparent Fatigue Limit of Bolted Joints under Transverse Vibration

In bolted joints subjected to transverse vibration, the lowest amplitude of the transverse vibration force in which the bolt did not break or loosen, that is the apparent fatigue limit, cannot be easily estimated although their essential fatigue limits can be estimated from specifications of the bolt. In this study, a method to predict the apparent fatigue limits from the essential fatigue limits and the tightening conditions has been proposed. In the proposed method the coefficient which is the strength by which the bolt thread is constrained by the internal thread, that is one of the tightening conditions, was only experimentally investigated. As the results of the prediction, it was verified that the proposed method is extremely useful for the prediction for the apparent fatigue limits.