Strategies of element selection when assigning the nominal tolerances

Strategies of element selection, which provide the maximal coefficients of external actions, tolerances, the minimal cost and optimum cost-quality proportion are offered. Criteria of element selection in each strategy are defined. The purpose of this paper is to develop the procedures of element selection, which are capable to take into account effects of external influences and cost characteristics of the nomenclature of elements. The convenient mathematical tool for solving these problems is the interval mathematics. In interval models, the external actions are taken into account by using the interval structures.