Feature Description
Failure mode and effects analysis - Glossary Definition: FMECA
NOTE: If the Diagnostic data is to be used in the FMECA the Diagnostic data derived in the Diagnostics must be saved to a file.
In order to perform an FMECA study in eXpress the Analyst must have first defined the "Object Failure modes", "Object Failure Effects" & "Design Effects" for the model. In addition the definition of "Intermediate Effects" can be used to simplify the FMECA content. Links to each of these generation Methods are given Below.
Two methods have emerged in eXpress for generating the "Object Failure modes" and "Object Failure Effects" to generate the "Design Failure Effects" data for a FMECA
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Static Method - Generation of Failure Modes and FMECA Design Effects Manually.
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Dynamic Method - Utilizing the eXpress Tests to Create the Design Effects Automatically (Preferred approach - with many man-hours savings)
Object Failure Modes:
Note: If "Object Functional Failure modes" are used, they may be generated automatically for the whole model at one time. However where non-detectable failure modes are needed the "Physics of Failure modes" need to be used (example: open decoupling capacitors are non-detectable so "Open and Short" should be used for these objects along with a Noise Immunity Class to automatically eliminate "Open" from detection test coverage) The choice of failure mode type (Functional vs Physics of failure) is an analyst decision to make.
Object Failure Effects:
LIkewise "Object Failure Effects" may be generated Automatically for the whole model at one time. These provide 1 to 1 Object Failure Effects with the Object failure modes. [Preferred method: Even with Manual Failure mode Generation]
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Manual Design Effects: Generation of each FMECA Design Effect Manually (Laborious - Time consuming)
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Auto Design Effects: One of the recent innovations in eXpress that helps the Analyst make FMECA's is the Dynamic Causes approach. "Creating Design Effects by making Model Tests to use Model Dependency Propagation for Design Effect Causes" Failure Effects with Dynamic Causes Overview [Preferred method]
NOTE: Analyst should run Hiearchical Design Error checks to insure all Failure Modes and Failure Effects are Correctly modeled before making FMECA
Helps for FMECA that apply to both Static and Dynamic FMECA Generation
