Abstract: The purpose of this article is to formulate the main provisions of a universal method for constructing a constant life diagrams (CLD) based on experimental data, which provides the creation of a scientifically based approach to systematization of data on the effect of average cycle stresses on the fatigue strength of polymer composite materials (PCM) under tension-compression conditions. It has been established that the forms of CLD for layered PCMs are very diverse (compared to metals, alloys and other structural materials), which is explained by a significant accumulation of fatigue damage under the action of variable stresses not only in those parts of the loading cycle when the zone of potential damage is stretched, but also when itshrinks. It has been established that, in the general case, layered PCMs are characterized by the presence of three CLD sections. Non-linear dependencies are proposed for approximating the end sections and linear ones for the middle section. An algorithm for selecting the middle section of the diagram based on the creation of a polynomial CLD model, implemented by the methods of the theory of experiment planning, is proposed.

Keywords: structural resources, fatigue testing of specimens, layered polymer composite materials, composite material fatigue, constant life diagrams.

For citation: Kryzhevich G. B. Effect of average cyclic stress on fatigue strength of polymer composite materials structures. Aerospace Engineering and Technology. 2023. Vol. 1. No. 1, pp. 63–73.