VDA-German Automotive Industry Society describes process of system FMEA building. I would like to highlight 3 key areas of VDA approach:
- Functional analysis
- Failure analysis
The process consists from following steps:
- Product breakdown to system levels
- Functional description of system
- Failure Analysis
- Risks Evaluation
- Risk Optimization
First step is about definition of system. Team breakdown system into several level which depend on scope of analysis eg. sensor-sensing
element-sensing element characteristics. Output of this step is system structure net.
In second step team define requirements, functions and characteristics into each element of product structure. Logic behind is describe how requirements should be ensured by functions and characteristics/parameters. Objective is to describe how system/product works. Output is functional net.
When system is described then for each requirement and function we add failure(s). On requirements level known as effect of failure. It´s situation when requirement is not followed or partialy followed.
Other steps like risk evaluation ( RPN = S x O x D) and risk optimization ( mitigate RPN´s above critical level) are simialar to standard FMEA process. Also See FMECA.
Key benefits of VDA approach:
- Structurized approach not form
- Requirements and functional descripiton of system/product
- Cause and Effect description based on functional analysis
- Better orientation and traceability