Рассмотрен вопрос установления зависимости точности и достоверности оценки надежности, проведенной экспертными методами, от полноты логической модели надежности технической сис-темы. Полнота модели определена видами технической совместимости, необходимыми для всестороннего анализа системы на стадии проектирования. По аналогии с функцией потерь Тагути предложено оценивать среднее квадратическое отклонение (СКО) экспертных оценок надежности, используя параболическую функцию, которая позволяет учесть прогрессивность величины СКО при снижении достоверности оценки.
An overall purpose of researches – improvement of assessment methods of engineering systems reliability at the stage of design. To achieve the end specified within the bounds of the investigation there was established that one of the most significant factors defining the effectiveness of the reliability assessment at the stage of designing is the completeness of a model used. For the assessment of model completeness by the example of a failure tree it was offered to determine a correlation between levels of a logical model of reliability and kinds of engineering consistency regulated by RSS 30709-2002 “Engineering Consistency. Terms and Definitions”. Within the bounds of the paper there is analyzed a minimum set of the sorts engineering consistency (dimensional consistency of system elements, compatibility of ele-ments according to reliability, interoperability) the account of which requires various degrees of detailed elaboration of a model and supposes the existence of corresponding source data including those established at the identification of logic connections between failures and the analysis of possible failures caused by a common reason. For the systematization of research results there is developed a matrix of correlation of analyzed kinds of engineering consistency with the levels of a failure tree and the values of the assessment of a quadratic means of deviation (QMD) of expected results. The mathematical dependences allowing the definition of QMD values at every level of the logic model of relia-bility are developed. To account for the progressive-ness of a QMD value at the decrease of assessment reliability by analogy with Taguchi function of losses it is offered to use a parabolic dependence. The approach offered is particularly urgent for methods where the accuracy of results obtained determines the degree of a risk of manufacturers caused by wrong or untimely management or technical decision-makings. The trend of risk changes for manufacturers depending on QMD of a resultant value allows explaining diagrams presented in the paper. The results obtained explain the dependence of accuracy and reliability of a reliability assessment on the completeness of use of the model and show a trend of the influence of parameters pointed out upon risk probability of manufacturers at the decisionmaking at the stage of designing.