Effect of Conical Angle and Thread Pitch on the Self-Loosening Performance of Preloaded Countersunk-Head Bolts

Abstract

This paper investigates the effect of the countersunk conical angle and thread pitch on the loosening performance of preloaded countersunk-head bolts that are subjected to harmonic transverse loading. A nonlinear mathematical model is used to predict the loosening performance. Cumulative differential loosening rotation of the bolt head is converted to a gradual loss in the bolt tension and joint clamp load. Model prediction of the self-loosening behavior is experimentally validated.