TABLE OF CONTENTS A system or its components can be treated as a black box or a lumped-parameter system, and the performances of the components of the components are observed over time. This reduces the reliability analysis to a one-dimensional problem involving time as the only variable. In such cases, the time-to-failure (TTF) of a system or a component of the system is the random variable. It should be pointed out that the term time could be used in a more general sense. In some situations, other physical scale measures, such as distance or length, may be appropriate for evaluation of system performance.
The TTF analysis is particularly suitable to assess the reliability of systems, repairable components, or both. For a system that is repairable after its failure, the time it would take to have it repaired to its operational status is uncertain; therefore, the time-to-repair (TTR) also is a random variable.
For a repairable system or component, its service life can be extended indefinitely if a repairable system available for service is greater than that of a nonrepairable system. This section focuses on characteristics of failure, repair, and availability of repairable systems by time-to-failure analysis.
Any system will fail eventually; it is simply a matter of time. Because of the presence of many uncertainties that affect the operation of a physical system, the time when the system fails to perform satisfactorily as intended is a random...
