ACCUMULATION OF PROGRESSING DEFORMATIONS OF THE THREADED JOINTS M16 UNDER LOW CYCLIC BENDING

Summary In some threaded joints, over a period of operation the conditions of compression are created, most likely owing to the prestress and bending caused by external loads. For elements in the cross-section in which the stresses are distributed unevenly, some standards approve using the exceeding of nominal values of yield limit short-cyclic longevity. The greater part of experiments is carried out under the influence of axial cyclic load on a joint, and the smaller part of experiments is carried out under the action of stretching and bending. The presented data show the fatigue proccess within the elements the working conditions of which depend on the influence of other elements. Results of the laboratory failure tests of the threaded joints produced from steel 25XIMΦ are used as a basis for investigation into of the stud-bolt M16. A static and kinematic theorem is used for the analysis of stress state of stud-bolt the initiation; propagation of fatigue cracks in the threaded joints is taken into acco...