Nacional'nyy issledovatel'skiy Mordovskiy gosudarstvennyy universitet im. N.P. Ogareva (Kafedra stroitel'nyh konstrukciy, Professor)
Saransk, Saransk, Russian Federation
Saransk, Saransk, Russian Federation
Saransk, Saransk, Russian Federation
Saransk, Saransk, Russian Federation
Saransk, Saransk, Russian Federation
UDK 620.17 Испытания механических свойств материалов. Механические испытания
The study deals with the kinetics of damage accumulation during exposure in a temperate climate. The research uses two types of polymer composites of significantly different climatic resistance as an example. The proposed method is the analysis of changes in the fractality index determined by the least-coverage method by tensile strain curves recorded with a high reading frequency (0.01 sec.). The fractality indices were calculated by analyzing the preceding time section that corresponds to 16 (24) experimental points, i.e., 0.16 sec. The levels of "critical" states corresponded to the minimum values of fractality indices ranged for the studied deformation curves from the beginning of loading to the level of reaching maximum tensile stresses by the specimens. The study included a field experiment on climatic aging of the studied polymers for one calendar year. We have recorded the changes in the elastic-strength characteristics of the samples after 45, 90, 180, 270 and 360 days. The results of the study showed significant differences in the damage accumulation kinetics of epoxy polymers impacted by tensile stresses, including those depending on the type of epoxy resin and hardener, as well as the duration of full-scale exposure. It was found that for climatically unstable compositions after just 180 days of climatic there is a grouping of "critical" points into ensembles similar in time, stress level, and relative elongation after stretching. At the same time, the climatic resistant polymers have a more uniform distribution of "critical" points along the deformation curves, which obviously allows them to successfully redistribute the occurring overstresses onto the workable structural elements and, consequently, to accept significantly higher levels of tensile loads and relative deformations.
epoksidnye polimery, krivye deformacii, nakoplenie povrezhdeniy, fraktal'nyy analiz, metod minimal'nogo pokrytiya
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