Investigations of Bolt Loosening Mechanisms : 1st Report, On the Bolts of Transversely Loaded Joints

Abstract

A theoretical analysis was made on the blot loosening mechanism on transversely loaded joints whose clamped parts slip relatively and the following were derived: (1) the condition necessary for the bolts to loosen by self rotation, (2) the physical meaning and the theoretical equation of the critical slippage between the clamped parts, (below which the bolts do not rotate), (3) the theoretical equation of the bolt loosening angle under the above-mentioned condition. Simple experiments were carried out to measure the friction coefficient of the bolts under the transverse slip of the clamped parts. Specifically, the critical slippage between the clamped parts, and the bolt loosening angle with the clamped parts making an arc slip were measured. The theoretical and empirical results were then compared.