抄録
Many papers have been published on the self loosening of bolted joints, making estimations of the locking effect from laboratory tests using a loosening test machine. However this kind of test method is only effective for the comparison of locking devices. In this paper we propose a method for estimating the absolute lock effect during actual machine operation ,that is construction machinery and material handling equipment. The authors found that there is a linear relation between axial tension and the time after the tightening on a log-log scale, in both static and dynamic loosening. Based on this relation, the authors propose a method for estimating the decrease of axial tension accurately after long hours of tightening by measuring the initial behavior as the bolt loosening evaluation chart.
