Failure Mode Effects and Analysis, Fault Tree Analysis, Multi-point Faults and EWQIMs
From its inception, Failure Mode and Effects Analysis has been historically used as a technique to evaluate the impact of single point failures on the functionality of products and processes. In late 2020, Omnex proposed the additional use of Design FMEAs as a tool to evaluate the impact of multi-point faults on the functional failure of complex products. Our proposal suggested the continued utilization of standard Design FMEA analysis; in accordance with the AIAG 4th edition guidelines and the AIAG-VDA FMEA Handbook approach, with some enhancements. For complex products whose performance is impacted by the simultaneous occurrence of multi-point faults, we have added additional columns to our FMEA analysis template to include notation for “AND” conditions, which require the occurrence of two or more potential causes of failure in order for the product to fail to perform a given function. The multi-point, “Failure Gate Type” - “AND” column designation is indicated in association with the individual causes.
The Omnex software enables companies to pursue varying levels of sophistication in their analysis. Some companies will begin with a DFMEA analysis then build that information into a basic Fault Tree. Other companies will pursue more complex analyses to address the need to develop more in-depth information for complex safety related products. These companies may choose to utilize Quantitative Fault Trees and Failure Mode Effects and Diagnostic Analyses, which can then be developed from calculations for single point fault metrics, latent point fault metrics, diagnostic coverage from estimates and Probabilistic Metric for Random Hardware Failures (PMHF) for Diagnostic Coverage Analysis & Hardware Metrics Calculations, also using Omnex software. Read the article to know more.