From 2bd6b307b9464190cbfccfc1966802812afb07cd Mon Sep 17 00:00:00 2001 From: Robin Clark Date: Sat, 30 Oct 2010 17:51:32 +0100 Subject: [PATCH] . --- fmmd_concept/fmmd_concept.tex | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fmmd_concept/fmmd_concept.tex b/fmmd_concept/fmmd_concept.tex index 67f116c..50fdbea 100644 --- a/fmmd_concept/fmmd_concept.tex +++ b/fmmd_concept/fmmd_concept.tex @@ -7,7 +7,7 @@ \abstract{ This paper proposes a methodology for creating failure mode models of safety critical systems, which -have a common notation +has a common notation for mechanical, electronic and software domains and apply an incremental and rigorous approach. @@ -328,10 +328,14 @@ give a value for the `safety level' for the equipment in a given environment. %%-• The operational profile (environmental stress factors). This uses MTFF and other statisical models to determine the probability of -failures occurring. A component failure mode, given its MTTF +failures occurring. +% +A component failure mode, given its MTTF the probability of detecting the fault and its safety relevant validation time $\tau$, contributes a simple risk factor that is summed -in to give a final risk result. Thus a statistical +in to give a final risk result. +% +Thus a statistical model can be implemented on a spreadsheet, where each component has a calculated risk, a fault detection time (if any), an estimated risk importance and other factors such as de-rating and environmental stress.