Reliability evaluation and selection of rolling element bearings

A procedure based on graph theory and matrix approach has been developed for the reliability evaluation and selection of a rolling element bearing for an application. The reliability of the bearing is evaluated considering reliability of its elements and their connections. This is modeled in terms of Reliability Graph of a Rolling Element Bearing. This graph is represented by an equivalent matrix called Rolling Element Bearing Reliability Permanent Matrix to obtain a matrix function-Reliability Permanent Function. This function is the characteristic of reliability of the rolling element bearing for the application. Reliability Index (R_I) of the bearing is also defined. It is a numerical measure of the bearing reliability and is obtained by substituting reliability value of the bearing elements and their connections in the matrix function. The paper also suggests how to assess these reliability values to obtain the index. The proposed procedure is useful for designers and practicing engineers for selection of an optimum bearing for a given application. The methodology is illustrated by means of an example.