STRENGTH PROPERTIES EVALUATION OF MATERIALS OF TECHNOLOGICAL MACHINES ELEMENTS BASED ON THE SYNERGETICALLY ORGANIZED SIGNALS OF ACOUSTIC EMISSION

A N Savel’Ev,N A Lokteva,E A Savel’Eva

doi:10.17073/0368-0797-2017-6-443-450

Abstract

One of the main tasks of metallurgical engineering when creating and operating technological equipment is to provide the necessary indicators of its reliability. Achieving the reliability of equipment during its manufacture is associated with the operational determination of the strength characteristics of the used materials, and, above all, their endurance limit. In this paper, the acoustic emission signal is used as a parameter for estimating the endurance limit of materials. To obtain a stable signal, based on the results of an analysis of the synergistic processes taking place in various physical media of lasers and masers, the approach of obtaining a synergistic signal EVN on the basis of dislocation medium has been applied. This made it possible to provide a sufficiently powerful emission signal characterizing the motion of dislocations during the formation of certain dislocation substructures. The experiment carried out on steel samples confirms the fact that using an organized fine-graded stretching of an acoustic signal sample allows the internal processes taking place in the materials to be evaluated. The results of the experiment make it possible to isolate the areas of elastoplastic deformation of the material with different dislocation velocities. Based on the fact that the deformable metals are self-bound systems with the realization of their loading of various dissipative mechanisms at different stages, that form the corresponding dislocation structures, relation between the intensity of EVN and the structural features of the BCS was established. Simultaneously, the time of change in the intensity of the EVN is compared with the limit of its endurance. This makes it possible to use the stresses emission accompanying the formation of dislocation structures together with the fixation of the voltage that arises in the material of the sample to determine the limit of endurance.

Highlights

Накопленная при этом от группы дислокаций энергия освобождается в виде достаточно мощной для ее анализа упругой волны
При этом значительная по величине мощность сигнала акустической эмиссии свидетельствует о том, что синергетический механизм организации эмиссионного сигнала на дислокационном уровне в металлах реализуем

Summary

Introduction

Это позволяет использовать сопровождающую формирование дислокационных структур эмиссию волн напряжений совместно с фиксацией возникающего в материале образца напряжения для определения предела выносливости. А это значит, что для выделения точек изменения доминирующего механизма накопления повреждений при циклическом нагружении достаточно одного (статического) этапа нагружения образца. При этом наличие локальных полей напряжений вокруг дислокаций при достаточно высокой скорости их движения создает необходимые условия для возникновения акустической эмиссии [14, 15, 17 – 19].

Results

Conclusion