Files

T

Benjamin Admin de140e564e feat(iace): FMEA P1 — open methodology anchors + bp_iace_fmea_kb

P1 of the auto-FMEA build plan: establish the public-domain methodology
foundation (no AIAG-VDA/SAE/IEC tables reproduced).
- fmea_data_sources.go: MIL-STD-882E severity (Cat I-IV→1-10) + probability
  (A-F→1-10 with per-hour λ bands), OccurrenceFromRate(λp·α), SeverityForCategory,
  MIL-STD-1629A CriticalityCm = λp·α·β·t. Own 1-10 projection, government-anchored.
- 4 versioned source docs (MIL-STD-1629A, MIL-STD-882E, NASA RCM, FMD-91/NPRD-91)
  ingested into the new RAG collection bp_iace_fmea_kb (whitelisted).
- Tests for all scales/mappings/criticality (green).

Next (P1 step 2): fetch FMD-91/NPRD-91 bulk λ/α tables from DTIC.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

2026-06-12 22:59:01 +02:00

2.1 KiB

Raw Blame History

FMECA methodology — MIL-STD-1629A (US public domain)

Canonical, citable methodology source for the IACE auto-FMEA. Ingested into the core RAG collection bp_iace_fmea_kb.

Source

Source: US DoD — MIL-STD-1629A, Procedures for Performing a Failure Mode, Effects and Criticality Analysis (cancelled 1998, still the de-facto FMECA reference)
License: US Government work — public domain (17 U.S.C. §105)
Attribution: Source: MIL-STD-1629A (US DoD), public domain
Retrieved: 2026-06 · Ref: everyspec / Wikipedia FMECA

Procedure (qualitative + quantitative)

Define the system, indenture levels and ground rules.
For each item/function: list failure modes → causes → local / next-higher / end effects.
Assign a severity category (I–IV, below).
Quantitative path (when failure-rate data exists): compute the modal criticality Cm = λp · α · β · t — λp part failure rate, α failure-mode ratio (fraction of part failures in this mode), β conditional probability the mode causes the analysed effect, t operating time. Item criticality Cr = Σ Cm.
Qualitative path (Task 101, no λ data): assign probability-of-occurrence levels A–E (Frequent → Extremely unlikely) instead of Cm.
Plot items on a severity × criticality matrix — the open analogue of an action-priority ranking (no copyrighted S×O×D RPN table needed).

Severity categories (MIL-STD-1629A / MIL-STD-882 lineage)

Cat	Name	Meaning
I	Catastrophic	May cause death or system loss
II	Critical	Severe injury / major damage
III	Marginal	Minor injury / minor damage
IV	Minor (Negligible)	No injury; unscheduled maintenance/repair

How used in IACE

The Cm formula and the severity × criticality matrix are the public-domain criticality backbone (CriticalityCm in fmea_data_sources.go).
λp/α come from NPRD-91 / FMD-91 (public domain); β and t from the project context.
Severity resolves through the linked EN ISO 12100 hazard (safety-FMEA bridge).

No AIAG-VDA / SAE J1739 / IEC 60812 content is reproduced.

2.1 KiB Raw Blame History Unescape Escape