Abstract

According to Knezevic [1] the purpose of existence of any functionable system is to do function ability work, which is considered to be done when the expected measurable function is performed through time. However, experience teaches us that in-service life of functionable systems is frequently beset by undesirable in-service disturbances resulting from a variety of physical mechanisms (overstress, wear out, natural phenomena and human interventions), some of which result in hazardous consequences to: the users; the natural environment; the general population and businesses. During the last sixty years, Reliability Theory has been used in an effort to predict these occurrences of undesirable in-service disturbances (frequently called failures). However, mathematically and scientifically speaking, the accuracy of these predictions, at best, were only ever valid to the time of the occurrence of the first undesirable in-service event, which is far from satisfactory in the respect of its expected life. Consequently, the main objective of this paper is to raise the question, how reliable are reliability predictions, based on the Reliability Function, in terms of mathematical and physical truth?.

Keywords: Reliability theory; Reliability function; Mathematical truth of reliability function; Physical truth of reliability function; Accuracy of reliability function