Metallurgy and Materials

A review and a brief analysis of four well-known constant-life diagram models of layered composites, most often encountered in scientific publications, are presented. The main advantages and disadvantages of models are noted. A special modification of the Harris diagram was proposed as an alternative to the given diagrams for engineering predictions of fatigue characteristics of layered composites at different asymmetry coefficients R of cyclic loading. Using the example of constructing the proposed diagram for CFRP AS4-PW open-hole specimens, a good agreement between the calculated and experimental data is shown, which makes it possible to hope for acceptable accuracy of the calculated estimates of fatigue strength characteristics of layered composites using this diagram. An example of using the diagram for estimation of fatigue life of CFRP Т300/5208 [45/0/-45/90]2s open-hole specimens under quasi-random program loading is presented.