The problem of increasing the efficiency of the construction machines functioning continues to be relevant in modern conditions. The downtime of construction equipment, in particular, of a single-bucket excavator (SBE), leads to a violation of the terms of work and to significant economic losses. One of the most loaded elements of a single-bucket excavator is a boom. Increasing the reliability of its work reduces the number of the machine failures greatly, and as a result reduces the cost of repairs and equipment downtime. The gamma-percentage fatigue life of the components, in particular, a single-bucket excavator boom, must correspond to the resource before discarding the machine. To prevent failures, it is necessary to increase the gamma-percentage fatigue life of the boom to the optimum value by changing the steel grade and the geometric characteristics. This will reduce the repair expenses and the damage from the downtime of the excavator as well as the mechanized machinery complex associated with its operation, thereby determining the relevance of the work presented.

One of the most important features in science and practice for ensuring the machines and their components’ reliability is the use one of the mathematics’ areas - theory of probability and mathematical statistics. Most textbooks on the theory of probability and mathematical statistics deal with infinitely large aggregates. Since even the sample’s representativeness does not allow fully describing the entire aggregate, this should be taken into account at the stage of calculation and design. These facts led to the need for the transition from the sample data to the general aggregate data of the final volume. For this transition, we used the graphical method, which allows going from the sample, for example, with a volume of n=10-100, to the general aggregate Nc=103-106 using the extrapolation method.

No abstract

No abstract