| Abstrakt: |
One of the important criteria for ensuring the long-lasting operation of polymeric materials is their resistance to cyclic loads. Currently, the range of polymeric materials expands significantly, which requires comprehensive studies of their properties, including the impact of cyclic loads of varying intensity. At the same time, there is a need to quantify the kinetics of failure accumulation in the polymer structure, including the possibility of analyzing the ongoing processes depending on the level of applied stresses and relative deformations. Earlier, the author's team proposed a technique to calculate the kinetics of failure accumulation. It involves the analysis of the data on deformation curves recorded with a high reading frequency (0.01 seconds), using methods of fractal analysis of time series. Numerical values of the fractality index are used as an indicator for a quantitative assessment of failure in the structural elements of the system under study. The onset of a "critical" state is recorded when the fractality index of the curve section under study falls below 0.5. However, in order to assess the effect of cyclic loads using the traditional approach to the study of polymer deformation curves under the mechanical loads, the total number of functioning structural elements at the beginning of loading remains unknown. The paper proposes an algorithm that allows, based on the results of experimental studies, to determine the initial number of functioning structural elements, as well as to quantify their decrease in the process of cyclic impact. The proposed approach is implemented by the example of samples of polymeric materials based on Etal-247 epoxy resin hardened with Etal-45TZ2. We separately calculated the kinetics of damage accumulation for each stage of loading, and built graphical dependencies of the change in the accumulated failure rate depending on the level of relative elongation and tensile stress. [ABSTRACT FROM AUTHOR] |
