Making Sense of Physics-of-Failure Based Approaches

PoF is an alternative approach / methodology to reliability that is focused on failure mechanism, failure site & root cause analysis instead of the more conventional approach that looks at failure modes & effects alone. The PoF approach characterizes reliability through lifetime distributions (probability distribution of frequency of fails v/s time) instead of hazard rates (failure rate v/s time). PoF approaches involve the followings steps:
1. Study of the hardware configuration: geometry, design, materials, structure
2. Study of life cycle loads: operational loads (power, voltage, bias, duty cycle) & environmental loads (temperature, humidity, vibration, shock)
3. Stress analysis: Stress-strength distributions/interference, cumulative damage assessment & endurance interference, FMEA, hypothesize failure mechanisms, failure sites & associate failure models, root cause analysis, calculate RPN's to rank & prioritize failures.
4. Reliability assessment: Rel metrics characterization, life estimation, operating/design margin estimation.
5. Interpret & apply results: Design tradeoffs & optimization, ALT planning & development, PHM & HUMS planning.