diff --git a/fmmd_concept/fmmd_concept.tex b/fmmd_concept/fmmd_concept.tex index ac3174c..d69e8a0 100644 --- a/fmmd_concept/fmmd_concept.tex +++ b/fmmd_concept/fmmd_concept.tex @@ -582,7 +582,12 @@ there are generally only a handful of SYSTEM level failure modes. \subsection{Outline of the FMMD process} \label{fmmdproc} FMMD builds {\fg}s of components from the bottom-up. -Thus the {\fg}s are minimal collections of components +The lowest level of components are termed base components. +These are the initial building blocks. +In Electronics these would be the individual +passive and active components on the parts~list. +In mechanics the the levers springs cogs etc. +Functional groups are collections of components that work together to perform a simple function. % We can perform a failure mode effects analysis on each of the component failure @@ -603,43 +608,100 @@ modes, the collected symptoms of the {\fg}. Because we can now have {\dcs} we can use these to form new {\fg}s and we can build a hierarchical `failure~mode' model of the SYSTEM. +The diagram in figure \ref{fig:fmmd_hierachy}, shows one stage +of the FMMD process. The resultant {\dc} may be used to +create higher level {\fg}s in later stages. %%- Need diagram of hierarchy %%- %%- -\vspace{20pt} -NEED DIAGRAM OF HIERACY -\vspace{20pt} +\begin{figure}[h] + \centering + \includegraphics[width=200pt,bb=0 0 331 249,keepaspectratio=true]{./fmmd_hierarchy.jpg} + % fmmd_hierarchy.jpg: 331x249 pixel, 72dpi, 11.68x8.78 cm, bb=0 0 331 249 + \caption{Example derived component created from the functional group comprised of components a,b,c} + \label{fig:fmmd_hierarchy} +\end{figure} + + +% \begin{figure}[h] +% \centering +% \includegraphics[bb=0 0 331 249,keepaspectratio=true]{./fmmd_hierarchy.jpg} +% % fmmd_hierarchy.jpg: 331x249 pixel, 72dpi, 11.68x8.78 cm, bb=0 0 331 249 +% \caption{Example derived component created from a functional group comprised of components a,b,c} +% \label{fig:fmmd_hiarchy} +% \end{figure} +% +% \vspace{20pt} +% NEED DIAGRAM OF HIERACY +% \vspace{20pt} \subsection{Environmental and Operational States and FMMD} -Introduce the ideas +Any real world sub-system will exist in a variable environment and may have several modes of operation. +In order to find all possible failures, the sub-system must be analysed for each operational state +and environment condition that can affect it. +Two design decision are required here, which objects should we +analyse the environment and operational states with respect to. +We could apply these conditions for analysis +to the functional group, the components, or the derived +component. -\paragraph {Environmental Conditions and FMMD} +\paragraph {Environmental Conditions and FMMD.} -HERE talk about environmental effects of a sub-system. +Environmental conditions are external to the +{\fg} and are often things that the system has no direct control over. +Consider ambient temperature, pressure or even electrical interferrence levels. -Define this further by identifying that -environmental conditions affect components +Environmental conditions may affect different components in a {\fg} +in different ways. -for instance a system may be speced for +For instance a system may be specified for 0 to 85oC operation, but some components may show failure behaviour between 60 and 85 +\footnote{Opto-islolators typically show marked performace decrease after +60oC whereas another common component, the resistor will be unaffected.}. +Environmental conditions will have an effect on the {\fg} and the {\dc} +but they will have specific effects on individual components. + +\paragraph{Design Decision.} +Environmental constraints will be applied to components. +A component will hold a set of Environmental states that +affect it. +Environmental conditions will apply SYSTEM wide, +but may only affect specific components. +%Some may not be required for consideration +%for the analysis of particular systems. \paragraph {Operational States and FMMD} -HERE talk about operational states of a sub-system -Define this further by stating that -operational states are effects on a functional group. -For instance a circuit may have a test line input. -The fnctional group will there fore have two -operational states, testing mode and normal mode. +Sub-systems may have specific operational states. +These could be a general health level such as +normal operation, graceful degradation or lockout. +Or they could be self~checking sub-systems that are either in a normal or self~check state. + +Operational states are conditions that apply to a functional group, not individual components. + + +\paragraph{Design Decision.} +Operational state will be applied to {\fg}s. \paragraph{UML Model of FMMD Analysis} -iDraw a UML model showing the components and the functional group +Draw a UML model showing the components and the functional group with the ENV and OP\_STAT classes associated with them + +\begin{figure}[h] + \centering + \includegraphics[width=400pt,bb=0 0 818 249,keepaspectratio=true]{./fmmd_env_op_uml.jpg} + % fmmd_env_op_uml.jpg: 818x249 pixel, 72dpi, 28.86x8.78 cm, bb=0 0 818 249 + \caption{UML model of Environmental and Operational states w.r.t FMMD} + \label{fig:env_op_uml} +\end{figure} + + + \subsection{Justification of wishlist} By applying the methodology in section \ref{fmmdproc}, the wishlist can diff --git a/fmmd_concept/fmmd_env_op_uml.dia b/fmmd_concept/fmmd_env_op_uml.dia new file mode 100644 index 0000000..d52b522 Binary files /dev/null and b/fmmd_concept/fmmd_env_op_uml.dia differ diff --git a/fmmd_concept/fmmd_env_op_uml.jpg b/fmmd_concept/fmmd_env_op_uml.jpg new file mode 100644 index 0000000..b217411 Binary files /dev/null and b/fmmd_concept/fmmd_env_op_uml.jpg differ diff --git a/fmmd_concept/fmmd_hierarchy.dia b/fmmd_concept/fmmd_hierarchy.dia new file mode 100644 index 0000000..593d447 Binary files /dev/null and b/fmmd_concept/fmmd_hierarchy.dia differ diff --git a/fmmd_concept/fmmd_hierarchy.jpg b/fmmd_concept/fmmd_hierarchy.jpg new file mode 100644 index 0000000..421345f Binary files /dev/null and b/fmmd_concept/fmmd_hierarchy.jpg differ