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8.1 Introduction All hydrosystems engineering problems involve many interconnected and in­terrelated components. The analysis of any hydrosystem problem should take those interactions into account so that the overall behavior of the system is modeled properly. In general, problems in hydrosystems engineering can be classified into (1) development problems, (2) design problems, and (3) opera­tional problems […]

Hwang et al. (1981) presented a review of literature related to system reliability evaluation techniques for small to large complex systems. A large system was defined as one that has more than 10 components and a moderate system as one which has more than 6 components and less than 10. Complex systems were defined as […]

Conceptually, fault-tree analysis, unlike event-tree analysis, is a backward anal­ysis that begins with a system failure and traces backward, searching for pos­sible causes of the failure. Fault-tree analysis was initiated at Bell Telephone Laboratories and Boeing Aircraft Company (Barlow et al., 1975). Since then, it has been used for evaluating the reliability of many different […]

This approach starts with a selection of key components and modes of opera­tion whose states (operational or failure) would decompose the entire system into simple series and/or parallel subsystems for which the reliability or failure probability can be evaluated easily. Then the reliability of the entire system is obtained by combining those of the subsystems […]

This is a very powerful method for system reliability evaluation. A path is defined as a set of components or modes of operation that leads to a certain outcome of the system. In system reliability analysis, the system outcomes of interest are those of failed state or operational state. A minimum path is one in […]

Evaluation of the reliability of simple systems, as described in the preceding section, is generally straightforward. However, many practical hydrosystems engineering infrastructures, such as water distribution systems, have neither series nor parallel configuration. Evaluation of the reliability for such com­plex systems generally is difficult. For some systems, with their components arranged in a complex configuration, […]

A standby redundant system is a parallel system in which only one compo­nent or subsystem is in operation (Fig. 7.7). It is a special case of K-out-of-M system with K = 1. If the operating component fails, then another component is operated. This type of system is different than the parallel system described in Sec. […]

This is a parallel system of M component for which the system would function if K (K < M) or more components function. This type of system also is called a partially redundant system. The general reliability formula for this system is rather cumbersome. For components having an identical reliability function, that is, ps, m(t) […]

For a parallel system, the entire system would perform satisfactorily if any one or more of its components or modes of operation is functioning satisfactorily; the entire system would fail only if all its components or modes of operation fail. In the framework of load-resistance interference for different modes of oper­ation, the failure probability of […]

In this section the reliability of some simple systems will be discussed. In the framework of time-to-failure analysis, availability of such systems will be pre­sented. Information such as this is essential to serve as the building blocks for determination of reliability or availability of more complex systems. 7.3.1 Series systems A series system requires that […]