ESTIMATION OF RELIABILITY INDICES OF A “LINEARLY AGEING” OBJECT

Abstract

This paper describes methodological difficulties when dealing with practical engineering challenges of reliability for non-stationary (time dependent/“ageing”) objects. A special case is considered when the object’s failure rate is linearly growing with operation time. An average lifetime of such object is defined. The result expression is reduced to the formula which is accessible to be used in engineering analyses. A formal way of substitution of a real non-stationary “ageing” object for a virtual stationary one is proposed. Besides, a constant failure rate of a virtual object is taken on the basis of additional considerations, in particular, on the basis of the condition ensuring the equality of the “life times” of both objects. The formulas are developed for calculation of the failure rate for a virtual stationary object, expressed through the parameters of the real object’s “ageing” characteristics. The efficiency of the suggested method is demonstrated by means of the solved problem about final probabilities of the states of the “linearly ageing” object and its availability factor, deduced in analytical form.