looking at FMEA process in more detail

using UML to describe it.

submission_thesis/CH2_FMEA/copy.tex

@@ -14,13 +14,27 @@ on the behaviour and safety of the system.''
 This chapter introduces Failure Mode Effect Analysis (FMEA).
 %It begins with a simple example to demonstrate the basic concept of FMEA
 %and then 
-It starts by looking at how we determine the failure modes associated with components.
+It starts with a generic conceptual overview of the process.
+It then looks at the stages of the FMEA process in greater detail, starting with
+how we determine the failure modes associated with components.
 Two common electrical components, the resistor and the operational amplifier
 and examined in the context of two sources of information that define failure modes.
-A simple example of an FMEA is then given.
-The four main variants are then described and finally we conclude by describing concepts
+%
+A simple example of an FMEA is then given, using a hypothetical {\ft} milli-amp reader.
+%
+The four main variants are then described and we then develop %conclude by describing concepts
+the concepts
 that underlie the usage and philosophy of FMEA.
-
+%
+We then return to the overall process of FMEA
+and model it using UML. 
+%
+By using UML we define relationships between the data objects 
+described at the start of this chapter.
+%
+The act
+of defining relationships between the data objects
+in FMEA raise questions about the nature of this process.
 
 
 
@@ -68,11 +82,49 @@ demonstrate a single  FMEA analysis stage, describes the four main variants of F
 and explores some concepts with which we can discuss and evaluate
 the effectiveness of FMEA.
 
+\section{FMEA Process}
+
+We begin FMEA with the basic, or starting components.
+This components are the sort we buy in or consider as pre-assembled modules.
+We need to know how these can fail. So our first relationship
+is between a {\bc} and its failure modes, see figure~\ref{fig:component_fm_rel}.
+
+%DIAGRAM of Base components and failure modes
+
+\begin{figure}[h]
+ \centering
+ \includegraphics[width=400pt]{./CH3_FMEA_criticism/component_fm_rel.png}
+ % component_fm_rel.png: 368x71 pixel, 72dpi, 12.98x2.50 cm, bb=0 0 368 71
+ \caption{Base Component to Failure Modes relationship}
+ \label{fig:component_fm_rel}
+\end{figure}
+
+The next stage is reasoning. We take a component failure
+mode and analyse its effect on some of the other components in the system.
+The result of this is a system level failure, or symptom.
+The analysis would typically be one line in a spreadsheet entry.
+and analysis to symptom relationship is generally % considered
+one-to-one, however here (see figure~\ref{fig:component_fm_rel_ana}), we allow for the possibility 
+of more than one failure symptom.
+%DIAGRAM of reasoning and Symptoms.
+
+\begin{figure}[h]
+ \centering
+ \includegraphics[width=400pt]{./CH3_FMEA_criticism/component_fm_rel_ana.png}
+ % component_fm_rel_ana.png: 369x184 pixel, 72dpi, 13.02x6.49 cm, bb=0 0 369 184
+ \caption{FMEA analyis entry data relationships}
+ \label{fig:component_fm_rel_ana}
+\end{figure}
+
+Figure ~\ref{fig:component_fm_rel_ana} defines the data relationships
+for FMEA. This model is expanded upon in the conclusion
+of this chapter.
 
 \section{Determining the failure modes of components}
 \label{sec:determine_fms}
 In order to apply any form of FMEA  we need to know the ways in which 
-the components we are using can fail.
+the components we are using can fail. In practise, this part of the process is guided by
+the standards to which we are seeking to conform to.
 %
 \footnote{A good introduction to hardware and software failure modes may be found in~\cite{sccs}[pp.114-124].}
 %
@@ -1147,14 +1199,8 @@ It   has a simple final result, a Safety Integrity Level (SIL) from 1 to 4 (wher
 %FMEA can be used as a term simple to mean Failure Mode Effects Analysis, and is
 %part of product approval for many regulated products in the EU and the USA...
 
-
-
-
-
-
 \section{FMEA used for Safety Critical Approvals}
 
-
 \subsection{DESIGN FMEA: Safety Critical Approvals FMEA}
 \begin{figure}[h]
  \centering
@@ -1164,7 +1210,7 @@ It   has a simple final result, a Safety Integrity Level (SIL) from 1 to 4 (wher
  \label{fig:tech_meeting}
 \end{figure}
 %Static FMEA, Design FMEA, Approvals FMEA 
-
+%
 Experts from Approval House and Equipment Manufacturer
 discuss selected component failure modes
 judged to be in critical sections of the product.
@@ -1172,11 +1218,6 @@ judged to be in critical sections of the product.
 This could be considered as a design check method, deliberately
 looking for weaknesses at a theoretical level.
 
-
-
-
-
-
 \subsection{DESIGN FMEA: Safety Critical Approvals FMEA}
 
 % \begin{figure}[h]
@@ -1194,6 +1235,22 @@ looking for weaknesses at a theoretical level.
 \end{itemize}
 
 
+\section{Conclusion}
+
+Returning to the FMEA model, we now show that
+figure holds for the five variants of FMEA discussed.
+We can however, extend this
+with subjective failure mode symptoms (see figure~\ref{fig:component_fm_rel_ana_subj_obj}).
+
+
+\begin{figure}[h]
+ \centering
+ \includegraphics{./CH3_FMEA_criticism/component_fm_rel_ana_subj_obj.png}
+ % component_fm_rel_ana_subj_obj.png: 694x303 pixel, 72dpi, 24.48x10.69 cm, bb=0 0 694 303
+ \caption{FMEA UML data representation with subjective system level failure modes.}
+ \label{fig:component_fm_rel_ana_subj_obj}
+\end{figure}
+
 
 % MOVED TO CH3: 15MAR2013
 % 

submission_thesis/CH3_FMEA_criticism/Makefile

@@ -3,7 +3,7 @@
 #
 # Place all .dia files here as .png targets
 #
-DIA = distcon.png
+DIA = distcon.png component_fm_rel.png component_fm_rel_ana.png component_fm_rel_ana_subj_obj.png
 
 
 doc: $(DIA)