Statistical Analysis of the Frequency of Damage Accumulation in the Structure of Epoxy Composites Under Tensile Loads

Statistical analysis of the frequency of damage accumulation in the structure of epoxy polymer samples subjected to tensile loads was performed. Samples of polymers produced on the basis of epoxy modified binder Etal-247 cured with hardener Etal-45M, which is a mixture of aromatic and aliphatic di- or polyamines, were chosen as the object of research. The main criterion for determining the coordinates of “critical” points was the results obtained using the author’s method for estimating changes in the fractality index based on the use of the least coverage method. The values of tensile stresses and relative elongations registered with high reading frequency (0.01 s) were used as input data. The levels of “critical” states corresponded to the values of fractality indices less than 0.5. The levels of accumulated damage were revealed with the excess leading to sample destruction. It has been established that in order to obtain the most objective results in the study of the damage accumulation kinetics, it is advisable to analyze not a single “most representative” sample, but a number of samples of the studied structure.