Basic Reliability Structures of Complex Technical Systems - New Contributions in Information Systems and Technologies - page 318

Fig. 3. Series reliability structure

Fig. 4. Pump unit as an example of series reliability structure

Parallel reliability structure is the one in which any element being capable of
fitness provides fitness of the whole system. Graphical model of the system with
parallel reliability structure (elements

E 1 ,E 2 , ..., E n )isshowninFig. 5.

Fig. 5. Parallel reliability structure

Parallel structure corresponds to systems that are experiencing the so-called
hot spare i.e., the system consists of more than one element of the considered
type, while the system needs as few as one element to carry out a task. Redundant
components are treated as the structural redundancy. All the elements of such
a system during operation subject to the same burdens associated with the
execution of the task by the system. An example of such a system are RAID
disks simultaneously recording the data in the manufacturing control system.

4.2 Complex Reliability Structure

The structure of complex systems are usually a combination of series and parallel
structure. Different parts of the system can then be considered as subsystems of
a series or parallel reliability structure. The series-parallel reliability structure
and the parallel-series reliability structure are the reducible ones (Fig. 6).