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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>
2.3 KiB
2.3 KiB
Failure-mode taxonomy & reliability data — FMD-91 / NPRD-91 (public domain)
Open component→failure-mode taxonomy and failure-rate (λ) / mode-ratio (α)
anchor for the IACE auto-FMEA. Ingested into bp_iace_fmea_kb. The bulk numeric
tables are fetched from the DTIC PDFs in a follow-up P1 step; this doc fixes the
sources + the per-component mode lists used to seed the gated library (P2).
Sources
- FMD-91 (RAC/DTIC) — Failure Mode / Mechanism Distributions — modes + mechanisms with % distribution (α) per part class. Public domain ("Approved for Public Release; Distribution Unlimited"). DTIC ADA259655.
- NPRD-91 / NPRD-95 (RAC/DTIC) — Nonelectronic Parts Reliability Data — field failure rates λ for mechanical / electromechanical parts. Public domain. DTIC ADA242083.
- MIL-HDBK-217F (US DoD) — electronic-part failure-rate models λ. Public domain (obsolete 1995 but legally free).
- Attribution:
Source: FMD-91 / NPRD-91 (RAC, DTIC), public domain - AVOID: Quanterion NPRD-2023 / FMD-2016 / EPRD-2024 (proprietary reissues), OREDA (commercial), FIDES tables (© DGA — read-only), ISO 14224 (copyrighted).
Failure modes by component class (open — FMD-91 + CC-BY-SA Wikipedia)
| Component class | Typical failure modes |
|---|---|
| Bearings | fatigue spalling/pitting, wear, brinelling, seizure, contamination |
| Gears | pitting, scuffing/scoring, tooth-fatigue fracture, wear |
| Shafts / fasteners / springs | fatigue fracture, fretting, loosening, set/relaxation |
| Seals / hoses / cylinders | leakage (external/internal), extrusion, hardening, rupture |
| Valves / pumps | stuck-open, stuck-closed, leakage, fail-to-open/close, degraded flow |
| Motors / contactors | winding short, open circuit, insulation breakdown, contact weld/stick |
| Sensors / cabling | drift/bias, loss of signal, intermittent, open/short |
FMD-91 additionally gives the % weighting (α) of each mode per class — that
is the mode-ratio in Cm = λp·α·β·t and lets the engine RANK modes rather than
enumerate them flatly.
How used in IACE
- Taxonomy → seeds/expands the gated failure-mode library (P2).
- λ (NPRD/217) × α (FMD-91) → mode rate →
OccurrenceFromRate→ 1–10 occurrence. - Each
source/licensetagged; allowlist rejects copyrighted/proprietary data.