STUDY ON SELF-LOOSENING OF BOLTED JOINTS TAKING ACCOUNT OF CHARACTERISTICS OF IMPULSIVE FRICTION.

In this paper is described a method to draw a self-loosening-limit diagram based on the theory of mechanism of the self-loosening. The method is presented taking account of the characteristics of impulsive friction on the interfaces of a fastener estimated from the results of an experiment in which the coefficient of impulsive friction on the test pieces is measured. The diagrams obtained by the method agree with the experimental results. And after the examination and comparison of those diagrams, the following are found effective to prevent the loosening: (1) the compressive force on the interfaces still remains, even when the tensile stress waves arising from an external impact come to the interface of fastened pieces and (2) the actual compressive stress on the pressure flank does not exceed the compressive yield point.