FMEA: Failure Mode and Effects Analysis

Overview

Risk priority via product of O·S·D ratings. Output typically utility (higher value = preferred).

Strengths

• •Method-specific: Risk priority via product of O·S·D ratings

Limitations

• •Assumes: Criteria preferences are independent (no synergistic interactions)
• •Assumes: Compensation is acceptable: high score on one criterion can offset low on another
• •Assumes: Decision matrix is complete (no missing values)

Assumptions to verify

• •Criteria preferences are independent (no synergistic interactions)
• •Compensation is acceptable: high score on one criterion can offset low on another
• •Decision matrix is complete (no missing values)

When not to use

• •Criteria strongly correlated → consider DEMATEL/ANP for interdependence
• •Non-compensatory preferences → consider outranking (ELECTRE/PROMETHEE)

Edge cases

• •See F.steps and D.parameters for FMEA-specific edge handling. recommendation_metadata.assumptions_to_verify also lists boundary conditions.

Common pitfalls

• •Hatalı: 'FMEA bu varsayımı kontrol etmeden uygulamak'. Doğrusu: Criteria preferences are independent (no synergistic interactions)
• •Hatalı: 'FMEA bu varsayımı kontrol etmeden uygulamak'. Doğrusu: Compensation is acceptable: high score on one criterion can offset low on another
• •Hatalı: 'FMEA bu varsayımı kontrol etmeden uygulamak'. Doğrusu: Decision matrix is complete (no missing values)
• •Hatalı: FMEA'yi 'Criteria strongly correlated → consider DEMATEL/ANP for interdependence' durumunda kullanmak: recommendation_metadata.not_recommended_when alternatif öneriyor.
• •Hatalı: FMEA'yi 'Non-compensatory preferences → consider outranking (ELECTRE/PROMETHEE)' durumunda kullanmak: recommendation_metadata.not_recommended_when alternatif öneriyor.

Worked example

1. 1.Adım 1 (F1): Step 1: Identify failure modes per item; collect three ratings per failure mode: Occurrence (O), Severity (S), Detection (D) on a 1-10 scale. Formül: O_{i}, S_{i}, D_{i} \in \{1, 2, \ldots, 10\} Anchor: Liu 2016, Ch.1 §1.2 Step 5 (p.7); Stamatis 2003 Ch.4
2. 2.Adım 2 (F2): Step 2: Compute Risk Priority Number for each failure mode i: RPN_i = O_i × S_i × D_i. Range: 1 (best) to 1000 (worst). Higher RPN = higher risk priority. Formül: \text{RPN}_{i} = O_{i} \times S_{i} \times D_{i}, \quad O_i, S_i, D_i \in \{1, 2, \ldots, 10\}, \quad \text{RPN}_i \in [1, 1000] Anchor: Liu 2016, Ch.1 §1.1 Eq.(1.1) (p.4); Stamatis 2003 p.99
3. 3.Adım 3 (F3): Step 3: Rank failure modes in descending order of RPN. The failure mode with the highest RPN receives rank 1 and is treated as the highest-priority risk for corrective action. After corrections, recalculate RPN to verify risk reduction. Formül: \text{rank}(i) = \text{rank in descending order of } \text{RPN}_i; \quad \text{RPN is recalculated post-correction} Anchor: Liu 2016, Ch.1 §1.1 (p.4); §1.2 Step 5 (p.7)

Commonly paired with

• •AHP + FMEA (high)
• •BWM + FMEA (high)
• •ENTROPY + FMEA (high)
• •CRITIC + FMEA (high)
• •SWARA + FMEA (high)

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