diff --git a/presentations/fmea/fmea_pres.tex b/presentations/fmea/fmea_pres.tex index 845a7dc..535edaf 100644 --- a/presentations/fmea/fmea_pres.tex +++ b/presentations/fmea/fmea_pres.tex @@ -88,9 +88,9 @@ For the sake of example let us choose resistor R1 in the OP-AMP gain circuitry. \begin{frame} \frametitle{FMEA Example: Milli-volt reader} \begin{itemize} - \pause \item \textbf{F - Failures of given component} The resistor could fail by going OPEN or SHORT (EN298 definition). + \pause \item \textbf{F - Failures of given component} The resistor (R1) could fail by going OPEN or SHORT (EN298 definition). \pause \item \textbf{M - Failure Mode} Consider the component failure mode SHORT - \pause \item \textbf{E - Effects} This will drive the minus input HIGH causing a LOW OUTPUT/READING + \pause \item \textbf{E - Effects} This will drive the minus input LOW causing a HIGH OUTPUT/READING \pause \item \textbf{A - Analysis} The reading will be out of normal range, and we will have an erroneous milli-volt reading \end{itemize} \end{frame} @@ -287,7 +287,7 @@ will return most cost benefit. \label{fig:f16missile} \end{figure} Emphasis on determining criticallity of failure. -Applies some baysian statistics (probabilities of component failues and those causing given system level failures). +Applies some Bayesian statistics (probabilities of component failures and those causing given system level failures). \end{frame} @@ -304,9 +304,9 @@ This will typically be the failure rate per million ($10^6$) or billion ($10^9$) hours of operation. \textbf{FMECA $\alpha$ value.} -The failure mode probability, usually dentoted by $\alpha$ is the probability of +The failure mode probability, usually denoted by $\alpha$ is the probability of is the probability of a particular failure -mode occuring within a component. +mode occurring within a component. %, should it fail. %A component with N failure modes will thus have %have an $\alpha$ value associated with each of those modes. @@ -318,7 +318,7 @@ mode occuring within a component. \textbf{FMECA $\beta$ value.} The second probability factor $\beta$, is the probability that the failure mode will cause a given system failure. -This corresponds to `Baysian' probability, given a particular +This corresponds to `Bayesian' probability, given a particular component failure mode, the probability of a given system level failure. \textbf{FMECA `t' Value} @@ -367,7 +367,7 @@ safety Integrity. FMEDA does force the user to consider all components in a system by requiring that a MTTF value is assigned for each failure~mode. This MTTF may be statistically mitigated (improved) -if it can be shown that selfchecking will detect failure modes. +if it can be shown that self-checking will detect failure modes. \end{frame} \begin{frame} @@ -378,7 +378,7 @@ The Failure modes are also classified as Detected or Undetected. This gives us four level failure mode classifications: Safe-Detected (SD), Safe-Undetected (SU), Dangerous-Detected (DD) or Dangerous-Undetected (DU), -and the probablistic failure rate of each classification +and the probabilistic failure rate of each classification is represented by lambda variables (i.e. $\lambda_{SD}$, $\lambda_{SU}$, $\lambda_{DD}$, $\lambda_{DU}$). \end{frame} @@ -516,6 +516,9 @@ judged to be in critical sections of the product. \end{frame} + +\subsection{FMEA - Better Metodology - Wish List} + \begin{frame} \frametitle{FMEA - Better Metodology - Wish List} @@ -525,7 +528,7 @@ judged to be in critical sections of the product. \pause \item Rigorous \pause \item Reasoning Traceable \pause \item re-useable - \pause \item + %\pause \item \end{itemize} %FMEDA is a modern extension of FMEA, in that it will allow for @@ -568,21 +571,25 @@ This creates an analysis hierarchy. \frametitle{FMMD - Outline of Methodology} \begin{itemize} \pause \item Select `{\fgs}' of components ( groups that perform a well defined function). - \pause \item Analyse the failure mode behaviour of a {\fg}. - \pause \item Collect the failures into Symptoms. - \pause \item Create a '{\dc}', where its failure modes are the symptoms of the {\fg} it was derived from. - \pause \item The {\dc} is now available to be used in higher level {\fgs}. + \pause \item Using the failure modes of the components create failure scenarios. + \pause \item Analyse each failure scenario of the {\fg}. + \pause \item Collect Symptoms. + \pause \item Create a '{\dc}', where its failure modes are the symptoms of the {\fg} it was derived from. + \pause \item The {\dc} is now available to be used in higher level {\fgs}. \end{itemize} \end{frame} -\subsection{example} +\subsection{FMMD - Example - Milli Volt Amplifier} \begin{frame} \frametitle{FMMD - Example - Milli Volt Amplifier} -We can begin to analyse this by looking for functional groups. +We can return to the milli-volt amplifier as an example to analyse. + +We can begin by looking for functional groups. The resistors would together to perform a fairly common function in electronics, that of the potential divider. -We can now take the failure modes for the resistors (OPEN and SHORT EN298) and see what effect each of these failures will have on the {\fg}. +So our first functional group is $\{ R1, R2 \}$. +We can now take the failure modes for the resistors (OPEN and SHORT EN298) and see what effect each of these failures will have on the {\fg} (the potential divider). \begin{figure} \centering \includegraphics[width=100pt]{./mvampcircuit.png} @@ -854,7 +861,7 @@ type analysis methods 19440. \begin{frame} \frametitle{FMMD - Failure Mode Modular De-Composition} -Note that for all possible double simultaneous failures the equation~\ref{eqn:fmea_state_exp} becomes +Note that for all possible double simultaneous failures the equation~\ref{eqn:fmea_state_exp2} becomes equation~\ref{eqn:fmea_state_exp2} essentially making the order $N^3$. The FMMD case (equation~\ref{eqn:anscen2}), is cubic within the functional groups only, not all the components in the system. @@ -873,17 +880,17 @@ not all the components in the system. \begin{frame} \frametitle{FMMD - Failure Mode Modular De-Composition} -\textbf{traceability} +\textbf{Traceability} Because each reasoning stage contains associations ($FailureMode \mapsto Sypmtom$) we can trace the `reasoning' from base level component failure mode to top level/system -failure, by traversing the tree/hierarchy. This is in effect documenting the framework of the reasoning. +failure, by traversing the tree/hierarchy. This is in effect providing a `framework' of the reasoning. \end{frame} \begin{frame} \frametitle{FMMD - Failure Mode Modular De-Composition} -\textbf{re-usability} +\textbf{Re-usability} Electronic Systems use commonly re-used functional groups (such as potential~dividers, amplifier configurations etc) Once a derived component is determined, it can generally be used in other projects. @@ -892,7 +899,7 @@ Once a derived component is determined, it can generally be used in other projec \begin{frame} \frametitle{FMMD - Failure Mode Modular De-Composition} -\textbf{total coverage} +\textbf{Total coverage} With FMMD we can ensure that all component failure modes have been represented as a symptom in the derived components created from them. We can thus apply automated checking to ensure that no @@ -909,9 +916,9 @@ missed in an analysis. \begin{itemize} \pause \item Addresses State Explosion - \pause \item Addresses total coverage of all cooomponents and their failure modes - \pause \item Provides tracable reasoning - \pause \item derived components are re-useable + \pause \item Addresses total coverage of all components and their failure modes + \pause \item Provides traceable reasoning + \pause \item derived components are re-use-able \end{itemize} \end{frame} diff --git a/presentations/fmea/mvamp.dia b/presentations/fmea/mvamp.dia index ccf9f9a..f6168b9 100644 Binary files a/presentations/fmea/mvamp.dia and b/presentations/fmea/mvamp.dia differ diff --git a/presentations/fmea/mvampcircuit.dia b/presentations/fmea/mvampcircuit.dia index 5fa0f36..a0d4ad1 100644 Binary files a/presentations/fmea/mvampcircuit.dia and b/presentations/fmea/mvampcircuit.dia differ diff --git a/presentations/fmea/pd.dia b/presentations/fmea/pd.dia index fceb3fc..1f18d93 100644 Binary files a/presentations/fmea/pd.dia and b/presentations/fmea/pd.dia differ