The article considers the stages of the process of fatigue failure of ship structural elements (SE) on the example of a ship's propeller shaft made of steel 35. Three stages of the fatigue failure process are distinguished: 1) incubation - from the moment of microcracks origin to the appearance of small cracks; 2) the development of small cracks up to the appearance of a macro-crack; 3) the growth of a macro-crack until the complete destruction of the SE. The second stage of fatigue failure is described - the stage of growth of a small fatigue crack. Based on the previously obtained conclusions on the small crack kinetics and the application of classical approaches to determining the duration of the macro-crack growth stage, using the stress intensity coefficient, the authors propose a mathematical model that allows us to numerically estimate the duration of the small crack growth stage. The practical significance of this stage is determined by its relative duration, which is most of the total durability of the.
small crack, fatigue failure, stages of failure, ships propeller shaft
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