Studying Acoustic Emission by Fitting the Destruction Models of a Composite According to the or Criterion and Mises Criterion

Abstract

This paper reports the established patterns of change in the acoustic emission signals by approximating the models of the destruction of a composite material in the form of a bundle of fibers according to the OR criterion and Mises criterion. It has been shown that increasing the coefficient that characterizes the ratio of the size of the elements of the composite material leads to that the pattern of change in the equivalent stresses according to the OR criterion is approaching the pattern of change by Mises criterion. At a certain value of the coefficient, according to the OR criterion, the equivalent stresses are aligned with a minimal deviation from each other. However, this alignment is limited to a specific change period. We have established patterns of change in the number of elements, which remain, as well as the signals of acoustic emission according to the OR criterion with the regularity of their change approaching that based on the Mises criterion. It has been shown that at the best approximation of the equivalent stresses according to the criteria there is a good agreement of the patterns of change in the number of a composite's elements, remaining in time, and the parameters for the formed signals of acoustic emission with their minimal deviation. It has been determined that the deviations in the parameters of acoustic emission signals are due to the difference in the rate of change in the equivalent stresses in proportion to approaching the time when a composite material starts breaking according to the OR criterion and Mises criterion. It has been determined that with the increasing deformation rate of a composite material, the patterns of change in the equivalent stresses approaching those based on the OR criterion and Mises criterion, the number of the remaining elements in the composite over time, and the parameters of acoustic emission signals are maintained. However, these patterns are observed at smaller intervals of time. The results obtained could be used in the study of the destructive processes of composite materials, taking into consideration the influence of various factors.