QUANTITATIVE ANALYSIS OF KINETICS ACCUMULATION OF DAMAGE IN THE STRUCTURE POLYMER MATERIALS AT A STRETCHING

Abstract

An approach to the study of the mechanism of deformation of composite materials in tension, based on the use of methods for analyzing curves "σ - ε", fixed with modern test equipment with a high frequency of reading (0,01 sec.). The change in time series of stress increase of the epoxy polymer depending on the step of fixing the readings is analyzed. It was found that with an increase in the step from 0,01 to 0,16 seconds, there is a structuring of the time curve, which allows us to identify zones with different patterns of accumulation of structural defects. Based on the analysis of the destruction of a solid body as a discrete-continuous process, the coordinates of the most "critical" points of the deformation curves are determined, which are characterized by the smallest negative indicators of stress increase over the previous time interval of 0,16 seconds, containing 2 ⁴ experimental points. An algorithm for estimating the rate of damage accumulation in the structure of polymer materials is proposed based on the analysis of stress increase with an increase in the elongation under tension. It is shown that the number of failures determined from the analysis of deformation curves recorded with high frequency allows us to quantify the critical level of defects that lead to the destruction of composites.