TABLE OF CONTENTS The objectives of this chapter are to present the following:
A comprehensive six key point definition of reliability.
Reliability as a conditional probability and its relationship to system effectiveness.
The concept of confidence level and the confidence limits on the true reliability.
No-failure performance determination.
The five types of failures.
The effects of age on reliability.
The effects of mission time on reliability.
The effects of application and operation environment stresses on reliability.
Reliability is the (1) conditional probability, at a given (2) confidence level, that the equipment will (3) perform its intended functions satisfactorily or without failure, i.e., within specified performance limits, at a given (4) age, for a specified length of time, function period, or (5) mission time, when used in the manner and for the purpose intended while operating under the specified application and operation environments with their associated (6) stress levels [1, p. 74].
The six key points in the definition of reliability, which are in italics, are elaborated upon next.
Probability is a ratio of two numbers, the numerator being the number of times the event, whose probability of occurrence is sought, has occurred (or can occur) and the denominator being the total number of events (or trials) undertaken (or all possible trials) out of which the desired number of events occurred. Reliability is a probability given by the ratio of the number...
