THE EFFECT OF THERMAL CYCLING ON THE PHYSICAL-MECHANICAL PROPERTIES OF POLYMER COMPOSITE MATERIALS: CRITICAL ANALYSIS, UNRESOLVED PROBLEMS AND PROMISING RESEARCH DIRECTIONS

Abstract

Polymer composite materials (PCMs) occupy an important place in modern materials science due to their unique combination of low density, high strength characteristics and corrosion resistance. Their application in aviation, space technology and construction is constantly expanding. However, operation at low temperatures is associated with a number of problems related to the degradation of properties under thermal cycling. Cyclic temperature changes cause the accumulation of internal stresses at the fiber-matrix interface. These stresses can exceed the strength limit of the material, leading to the appearance of microcracks and delamination. Understanding the mechanisms of degradation is necessary to predict the service life of structures. The combined effect of thermal cycles and moisture, which enhances matrix destruction, is particularly dangerous. In this work, a critical analysis of 61 open scientific sources is performed. It is shown that, despite extensive experimental data, existing approaches have fundamental limitations. The empirical logarithmic degradation law has no physical justification. Methods for measuring residual stresses show a scatter of up to 17% and do not reflect the kinetics of relaxation processes in a viscoelastic matrix. The effectiveness of nanomodification is not scalable to large-sized products. There are no models that take into account the combined effect of thermal cycles, moisture and mechanical loads. Based on the identified contradictions, directions for further research are formulated and methods for solving unresolved problems are proposed.