From e30ff224d7593543456cafb7dc1d169aaed0f73a Mon Sep 17 00:00:00 2001 From: "Robin P. Clark" Date: Wed, 5 Sep 2012 17:22:47 +0100 Subject: [PATCH] For meeting with AF 07SEP2012 --- submission_thesis/CH4_FMMD/copy.tex | 55 ++++++++++++++++------------- 1 file changed, 31 insertions(+), 24 deletions(-) diff --git a/submission_thesis/CH4_FMMD/copy.tex b/submission_thesis/CH4_FMMD/copy.tex index 8cc776f..b81aa9d 100644 --- a/submission_thesis/CH4_FMMD/copy.tex +++ b/submission_thesis/CH4_FMMD/copy.tex @@ -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} 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} 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 % - \node[symptom] (PDHIGH) at (\layersep*2,-1.0) {$PD_{HIGH}$}; - \node[symptom] (PDLOW) at (\layersep*2,-3.0) {$PD_{LOW}$}; + \node[symptom] (PDHIGH) at (\layersep*2,-1.0) {HighPD}; + \node[symptom] (PDLOW) at (\layersep*2,-3.0) {LowPD}; \path (R1OPEN) 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 a {\dc} to represent this potential divider: 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 {\fg} and creating from it a {\dc}. % 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 % - \node[symptom] (PDHIGH) at (\layersep*2,-7) {$PD_{HIGH}$}; - \node[symptom] (PDLOW) at (\layersep*2,-8.6) {$PD_{LOW}$}; + \node[symptom] (PDHIGH) at (\layersep*2,-7) {HighPD}; + \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). 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, -as represented in figure~\ref{fig:dc2}. +% HTR 05SEP2012 This model now has two stages of analysis hierarchy, as represented in figure~\ref{fig:dc2}. 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. -\begin{figure}[h] - \centering - \includegraphics[width=225pt]{./CH4_FMMD/dc2.png} - % dc2.png: 635x778 pixel, 72dpi, 22.40x27.45 cm, bb=0 0 635 778 - \caption{Hierarchy representing the two stage FMMD analysis - (i.e. two `$\derivec$' processes taking {\fgs} and creating {\dcs}) for the non-inverting amplifier} - \label{fig:dc2} -\end{figure} +% HTR 05SEP2012 \begin{figure}[h] +% HTR 05SEP2012 % HTR 05SEP2012 \centering +% HTR 05SEP2012 \includegraphics[width=225pt]{./CH4_FMMD/dc2.png} +% HTR 05SEP2012 % dc2.png: 635x778 pixel, 72dpi, 22.40x27.45 cm, bb=0 0 635 778 +% HTR 05SEP2012 \caption{Hierarchy representing the two stage FMMD analysis +% HTR 05SEP2012 (i.e. two `$\derivec$' processes taking {\fgs} and creating {\dcs}) for the non-inverting amplifier} +% HTR 05SEP2012 \label{fig:dc2} +% 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}. \begin{figure}[h] \centering \includegraphics[width=300pt]{./CH4_FMMD/eulerfmmd.png} % 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} \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 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 -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 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 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 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 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 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}, -we increase the tracability in the reasoning applied to to the FMEA process.}. +% +An analysis report is generated as part of the {\fg} to {\dc} +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}.