Within BlockSim, a subdiagram block inherits some or all of its properties from another block diagram. This allows the analyst to maintain separate diagrams for portions of a system and incorporate those diagrams as components of another diagram. With this technique, it is possible to generate and analyze extremely complex diagrams representing the behavior of many subsystems in a manageable way. In Figure 4.22, Subdiagram Block A in the top diagram represents the series configuration of the subsystem reflected in the middle diagram, while Subdiagram Block G in the middle diagram represents the series configuration of the subsubsystem in the bottom diagram. Figure 4.23 again illustrates this concept.
Figure 4.22: Illustration of subdiagrams.
Figure 4.23: An RBD of two computer systems in series where each computer system inherits its diagram from another subdiagram.
For this example, obtain the reliability equation of the system shown in Figure 4.23.
The system reliability equation is:
(9)
Now:
(10)
Since the structures of the computer systems are the same, RComputer1 = RComputer2, thus substituting Eqn. (10) into Eqn. (9) yields:
When using BlockSim to compute the equation, the software will return Eqn. (9) for the system and Eqn. (10) for the subdiagram in the equation viewer. Even though BlockSim will make these substitutions internally when performing calculations, it does show them in the System Reliability Equation window.
See Also:
RBDs and Analytical System Reliability
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