Evolution of Design, Use and Strength Calculations of Screw Threads and Threaded Joints

Abstract

Threaded joints are in wide use in different structures, machines and devices and these facts lead to new designs of threaded parts and joints having new useful properties for different conditions of loading. Therefore, in spite of the fact that there are a lot of different literature where designs of threaded parts and calculation methods are given, it is necessary to make some systematization to trace common direction on which goes the evolution of design of threaded parts, threaded joints and their calculation methods. Between different problems, have been considered by researches, the most important problem, in our opinion, are fundamental problems such as development of structures of threaded parts to achieve new useful properties, expansion of use area and development of strength calculation to more exact consideration of a stress condition on different methods of loading. Use new, more exact methods of calculations with use of different materials gives a possibility to increase a reliability of the threaded joints and decrease expenses of their manufacture, assembly, repair and operation as threaded joints as devices and machines as a whole. In our previous work 1 apart from other problems the fundamental problem of the strength of the threaded joints-how the external axial load is distributed on the threads-in historical aspect was considered and was shown that this distribution in the pair of a bolt and a nut is extremely uneven. This fact leads to large dimensions of the threaded parts and, of course, to large dimensions of the joints as compared with the parts having no threads. In this article the evolution of structures of the threaded joints and methods of strength calculation are considered. It should be noticed that present work is natural sequel of work 1 and may be considered as addition.