Assessment of the level of reliability of the technical system at the design stage

To reduce the number of tested prototypes of machines and types of tests, their duration, and, consequently, to save costs for their implementation, the determination of the assessment of the level of reliability of the technical system during its design contributes. The article considers a calculation method that allows, in accordance with the selected criteria for achieving the technical system of the limit state, to estimate the average resource before the overhaul of the machine at the stage of its design. With this in mind, a structural diagram of a technical system was compiled for a machine-tractor unit based on a general-purpose tractor of class 5, the analysis of which made it possible to perform a probabilistic description of events that determine the development of resources of aggregates and machine systems, a probabilistic reliability function of a complex technical system was recorded. The data on failures obtained from the results of controlled operation of tractor units - analogues and the values of reliability indicators of the components of the technical system calculated on their basis (the probability of failure-free operation - the indicator of failure-free operation) made it possible to determine the reliability (the probability of failure-free operation) of the technical system itself. (At the same time, only failures characterizing the imperfection of the designs of components, aggregates and MTA systems were taken into account). This, in turn, makes it possible to assess its level of durability: by applying the Weibull distribution of the service value (resource), the value of the average resource of the tractor unit before major repairs was obtained, which corresponds to the technical task. The study of the level of reliability of the technical system from its constituent elements showed that with the same increase in the reliability of the constituent elements, the power plant and the working equipment of the tractor unit have a significant impact. The method proposed in the article allows us to solve the problem of redistributing reliability between the elements that make up a complex technical system.