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For meeting with AF 07SEP2012

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Robin P. Clark 2012-09-05 17:22:47 +01:00
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submission_thesis/CH4_FMMD/copy.tex
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@ -83,7 +83,7 @@ This {\dc} has a set of failure modes: we can thus treat it as a `higher~level'
Because a {\dc} has a set of failure modes we can use it in higher level {\fgs} Because a {\dc} has a set of failure modes we can use it in higher level {\fgs}
which in turn produce higher level {\dcs}. which in turn produce higher level {\dcs}.
% %
We can then use {\dcs} to then build further {\fgs} until a hierarchy of {\fgs} We can then use these {\dcs} to build further {\fgs} until a hierarchy of {\fgs}
and {\dcs} has been built, converging to a final {\dc} and {\dcs} has been built, converging to a final {\dc}
at the top of the hierarchy. at the top of the hierarchy.
% %
@ -582,8 +582,8 @@ This is represented in the DAG in figure \ref{fig:fg1adag}.
% Potential divider failure modes % Potential divider failure modes
% %
\node[symptom] (PDHIGH) at (\layersep*2,-1.0) {$PD_{HIGH}$}; \node[symptom] (PDHIGH) at (\layersep*2,-1.0) {HighPD};
\node[symptom] (PDLOW) at (\layersep*2,-3.0) {$PD_{LOW}$}; \node[symptom] (PDLOW) at (\layersep*2,-3.0) {LowPD};
\path (R1OPEN) edge (PDHIGH); \path (R1OPEN) edge (PDHIGH);
\path (R2SHORT) edge (PDHIGH); \path (R2SHORT) edge (PDHIGH);
@ -601,7 +601,7 @@ This is represented in the DAG in figure \ref{fig:fg1adag}.
We can now create % formulate We can now create % formulate
a {\dc} to represent this potential divider: a {\dc} to represent this potential divider:
we name this \textbf{PD}. we name this \textbf{PD}.
This {\dc} will have two failure modes, $PD_{HIGH}$ and $PD_{LOW}$. This {\dc} will have two failure modes, $HighPD$ and $LowPD$.
% HTR 05SEP2012 We use the symbol $\derivec$ to represent the process of taking the analysed % HTR 05SEP2012 We use the symbol $\derivec$ to represent the process of taking the analysed
% HTR 05SEP2012 {\fg} and creating from it a {\dc}. % HTR 05SEP2012 {\fg} and creating from it a {\dc}.
% HTR 05SEP2012 The creation of the {\dc} \textbf{PD} is represented as a % HTR 05SEP2012 The creation of the {\dc} \textbf{PD} is represented as a
@ -826,8 +826,8 @@ as {\fcs} in table~\ref{tbl:ampfmea1}.
% Potential divider failure modes % Potential divider failure modes
% %
\node[symptom] (PDHIGH) at (\layersep*2,-7) {$PD_{HIGH}$}; \node[symptom] (PDHIGH) at (\layersep*2,-7) {HighPD};
\node[symptom] (PDLOW) at (\layersep*2,-8.6) {$PD_{LOW}$}; \node[symptom] (PDLOW) at (\layersep*2,-8.6) {LowPD};
@ -891,30 +891,30 @@ as {\fcs} in table~\ref{tbl:ampfmea1}.
%in hand (say milli-volt signal amplification). %in hand (say milli-volt signal amplification).
For this amplifier configuration we have three {\dc} failure modes; {\em AMP\_High, AMP\_Low, LowPass}. % see figure~\ref{fig:fgampb}. For this amplifier configuration we have three {\dc} failure modes; {\em AMP\_High, AMP\_Low, LowPass}. % see figure~\ref{fig:fgampb}.
This model now has two stages of analysis hierarchy, % HTR 05SEP2012 This model now has two stages of analysis hierarchy, as represented in figure~\ref{fig:dc2}.
as represented in figure~\ref{fig:dc2}.
From the analysis in table \ref{tbl:ampfmea1} we can create the {\dc} {\em NONINVAMP}, which From the analysis in table \ref{tbl:ampfmea1} we can create the {\dc} {\em NONINVAMP}, which
represents the failure mode behaviour of the non-inverting amplifier. represents the failure mode behaviour of the non-inverting amplifier.
\begin{figure}[h] % HTR 05SEP2012 \begin{figure}[h]
\centering % HTR 05SEP2012 % HTR 05SEP2012 \centering
\includegraphics[width=225pt]{./CH4_FMMD/dc2.png} % HTR 05SEP2012 \includegraphics[width=225pt]{./CH4_FMMD/dc2.png}
% dc2.png: 635x778 pixel, 72dpi, 22.40x27.45 cm, bb=0 0 635 778 % HTR 05SEP2012 % dc2.png: 635x778 pixel, 72dpi, 22.40x27.45 cm, bb=0 0 635 778
\caption{Hierarchy representing the two stage FMMD analysis % HTR 05SEP2012 \caption{Hierarchy representing the two stage FMMD analysis
(i.e. two `$\derivec$' processes taking {\fgs} and creating {\dcs}) for the non-inverting amplifier} % HTR 05SEP2012 (i.e. two `$\derivec$' processes taking {\fgs} and creating {\dcs}) for the non-inverting amplifier}
\label{fig:dc2} % HTR 05SEP2012 \label{fig:dc2}
\end{figure} % HTR 05SEP2012 \end{figure}
We can also represent the hierarchy as an Euler diagram, where the curves We can represent the hierarchy as an Euler diagram, where the curves
define the components and {\dcs} used to form the INVAMP model, see figure~\ref{fig:eulerfmmd}. define the components and {\dcs} used to form the INVAMP model, see figure~\ref{fig:eulerfmmd}.
\begin{figure}[h] \begin{figure}[h]
\centering \centering
\includegraphics[width=300pt]{./CH4_FMMD/eulerfmmd.png} \includegraphics[width=300pt]{./CH4_FMMD/eulerfmmd.png}
% eulerfmmd.png: 413x207 pixel, 72dpi, 14.57x7.30 cm, bb=0 0 413 207 % eulerfmmd.png: 413x207 pixel, 72dpi, 14.57x7.30 cm, bb=0 0 413 207
\caption{FMMD analysis of the INVAMP represented as an Euler diagram, showing the relationships between base and derived components.} \caption{FMMD analysis of the INVAMP represented as an Euler diagram, showing how
the components have been grouped into {\fgs} and then used as {\dcs} to build the analysis hierarchy.}
\label{fig:eulerfmmd} \label{fig:eulerfmmd}
\end{figure} \end{figure}
@ -927,7 +927,9 @@ down to the base component failure modes, %leaves of the tree (the leaves being
and thus determine all possible causes for and thus determine all possible causes for
the three high level symptoms, i.e. the failure~modes of the non-inverting amplifier {\dc} {\em INVAMP}. the three high level symptoms, i.e. the failure~modes of the non-inverting amplifier {\dc} {\em INVAMP}.
Knowing all possible causes for a top level event/failure~mode Knowing all possible causes for a top level event/failure~mode
is extremely useful. Were the top level event to be classified as catastrophic for instance, is extremely useful.
%
Were a particular top level event to be classified as catastrophic for instance,
we could use this information we could use this information
to strengthen components that could cause that particular top level event/failure. to strengthen components that could cause that particular top level event/failure.
% %
@ -1455,10 +1457,10 @@ The UML meta model above (see figure~\ref{fig:cfg}) describes a hierarchical str
This is because, as {\dcs} inherit the properties of This is because, as {\dcs} inherit the properties of
components, {\dcs} may be used to form {\fgs}. components, {\dcs} may be used to form {\fgs}.
% %
Consider the hierarchy from the example in figure~\ref{fig:dc2}. Consider the hierarchy from the example in figure~\ref{fig:eulerfmmd}. % ~\ref{fig:dc2}.
The lowest level in this hierarchy are the {\bcs}, the resistors and the op-amp. The lowest level in this hierarchy are the {\bcs}, the resistors and the op-amp.
% %
The resistors are collected into a {\fg}, and the ${PD}$ derived component created from its analysis, is shown above the {\fg}. The resistors are collected into a {\fg}, and the ${PD}$ derived component created from its analysis, is shown enclosing R1 and R2. % above the {\fg}.
% %
As this derived component inherits the properties of a component, we may use As this derived component inherits the properties of a component, we may use
it in {\fg} higher in the hierarchy. it in {\fg} higher in the hierarchy.
@ -1468,9 +1470,14 @@ with the op-amp.
% %
This {\fg} is now analysed and a {\dc} created to This {\fg} is now analysed and a {\dc} created to
represent the failure mode behaviour of the {\em INVAMP}. represent the failure mode behaviour of the {\em INVAMP}.
An analysis report is generated for each {\fg} to {\dc} %
process\footnote{By having an analysis report report for each analysis stage, i.e. {fg} to {\dc}, An analysis report is generated as part of the {\fg} to {\dc}
we increase the tracability in the reasoning applied to to the FMEA process.}. process. %\footnote
{By having an analysis report report for each analysis stage, i.e. {\fg} to {\dc},
we add traceability to the reasoning applied to to the FMEA process.}
%
Traditional FMEA has one large reasoning stage, that of component failure mode
directly to system level failure.
% %
We may now use the {\em INVAMP} {\dc} in even higher level {\fgs}. We may now use the {\em INVAMP} {\dc} in even higher level {\fgs}.