PowerPoint Presentation

Failure Mode and Effects Analysis (FMEA)9/28/2013Ohio University - Dr. Cyders1FMEA is a design tool for assessing risk associated with the different ways (modes) in which a part or system can fail, identifies the effects of those failures, and provides a structure for revising the design to mitigate risk where necessary.

Inductive process, asks question If this failure occurred, then what could happen?Provides a method for quantitative analysis of riskUseful for comparing design concepts and refining designsDocuments safety review in an easy-to-read format

9/28/2013Ohio University - Dr. Cyders2Process Steps:1: Identify modes of failure (e.g.: car wont stop)2: Identify consequences & related systems for each mode3: Rate the Severity (S) of each effect 4: Identify potential root causes for each failure mode5: Rate the Probability of Occurrence (O) of each root cause 6: Identify process controls and indicators (e.g.: brake squeal)7: Rate Detectability (D) of each mode/root cause8: Calculate risk priority (S*O*D) and criticality (S*O) 9: Use design to mitigate high-risk or highly critical failures, and re-assess to ensure goals have been achieved

9/28/2013Ohio University - Dr. Cyders3Example:BatteryHeadlightSwitchPossible Failure Modes:Light doesnt turn onLight doesnt turn off

Possible Consequences:Light doesnt turn onDriver cant see obstaclesCar inoperable at night (8)Light doesnt turn offBattery diesCar wont start (10)Possible Root Causes:Light doesnt turn onBattery dead (8)Broken wire (3)Headlight out (10)Switch corroded (2)Switch broken (3)

9/28/2013Ohio University - Dr. Cyders4Example:BatteryHeadlightSwitchPossible Failure Modes:Light doesnt turn onLight doesnt turn off

Possible Consequences:Light doesnt turn onDriver cant see obstaclesCar inoperable at night (8)Light doesnt turn offBattery diesCar wont start (10)Possible Root Causes:Light doesnt turn offShort circuit in switch (2)Operator error (left on) (8)

9/28/2013Ohio University - Dr. Cyders5Example:BatteryHeadlightSwitchControls/indicators:Light doesnt turn onUser notices lights on in darkLight doesnt turn offUser notices lights on in dark

Detectability:Light doesnt turn on (6)User notices lights on in darkUser doesnt notice lights not on during dayLight doesnt turn off (6)User notices lights on in darkUser doesnt notice lights not on during day

59/28/2013Ohio University - Dr. Cyders6Example:Possible EffectRoot CauseSODRPNCrit.Car inoperable at nightBattery dead 108648080Broken wire 8314424Headlight out 81048080Switch corroded829616Switch broken 8314424Failure Mode: Light doesnt turn on

69/28/2013Ohio University - Dr. Cyders7Example:Possible EffectRoot CauseSODRPNCrit.Car inoperable at nightBattery dead 108216080Broken wire 836030Headlight out 61012060Switch corroded824020Switch broken 836030Failure Mode: Light doesnt turn onRedesign: Use two headlights instead of one, add visual lights-on display in console.

79/28/2013Ohio University - Dr. Cyders8Example:Possible EffectRoot CauseSODRPNCrit.Car wont start Short circuit in switch 102714020Operator error856080Failure Mode: Light doesnt turn off

89/28/2013Ohio University - Dr. Cyders9Example:Possible EffectRoot CauseSODRPNCrit.Car wont start Short circuit in switch 10224020Operator error816080Failure Mode: Light doesnt turn offRedesign: Add audible indicator when drivers door is opened while lights are on, add visual lights-on display in console.

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