36 lines
2.0 KiB
TeX
36 lines
2.0 KiB
TeX
{
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\section{Introduction}
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This chapter describes a process for taking a functional group of components,
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applying FMEA analysis on all the component failure modes possible in that functional~group,
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and then determining how that functional group can fail.
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%
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%
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With this information, we can treat the functional group
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as a component in its own right.
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This new component is a derived from the functional~group.
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In the field of safety engineering this derived component correspond to a low~level sub-system.
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%The technique uses a graphical notation, based on Euler\cite{eulerviz} and Constraint diagrams\cite{constraint} to model failure modes and failure mode common symptom collection. The technique is designed for making building blocks for a hierarchical fault model.
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%
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Once the failure modes have been determined for a sub-system/derived~component,
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this derived component can be combined with others to form functional groups
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to model
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higher level sub-systems/derived~components.
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%
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In this way a hierarchy to represent the fault behaviour
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of a system can be built from the bottom~up. This process can continue
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until there is a complete hierarchy representing the failure mode
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behaviour of the entire system under analysis.
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%FMMD hierarchy
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Using the FMMD technique the hierarchy is built from the bottom up to ensure complete failure mode coverage.
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Because the process is bottom-up, syntax checking and tracking can ensure that
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no component failure mode can be overlooked.
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Once a hierarchy is in place it can be converted into a fault data model.
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From the fault data model, automatic generation
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of FTA\cite{nasafta} (Fault Tree Analysis) and mimimal cuts sets\cite{nucfta} are possible.
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Also statistical reliability/probability of failure~on~demand\cite{en61508} and MTTF (Mean Time to Failure) calculations can be produced
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automatically, where component failure mode statistics are available\cite{mil1991}.
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This chapter focuses on the process of building the blocks, the symptom extraction or abstraction process, that is key to creating an FMMD hierarchy.
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}
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