Daniel Sillivant University of Alabama in Huntsville - PowerPoint Presentation

Slide1

Daniel SillivantUniversity of Alabama in HuntsvilleDaniel.Sillivant@UAH.edu

Using FMEA to Address Warranty DurationSlide2

FMEA ProcessReliability Block DiagramsCritical Items ListMTBF and Reliability CalculationsOC Curve for Number of Tests

Warranty DecisionsOutlineNovember 3-4, 2015

RAM VIII Training Summit2Slide3

FMEA: Methodology designed to identify potential failure modesBasic Procedure:

Identify the item(s) to be analyzedIdentify the Function(s),

Failure Mechanism(s) (Cause)Failure Mode(s) (How)Failure Effect(s) (Results)Evaluate the issues identified by the analysisAdditional ToolsCritical Items List (CIL)Reliability Block Diagram (RBD)

Reliability Calculations

Warranty Confidence - OC Curves

Physical Testing

Failure

Mode and Effect Analysis (

FMEA)

November 3-4, 2015

RAM VIII Training Summit

3Slide4

TransportationPackingHandling at each stage of shipment from origin to end userTruck, Rail, Aviation & Sea

StorageDistribution chainAt end userOperational conditions of use (intrinsic)Result from system functionAmbient conditions

of use (extrinsic) Result from environmental exposure and from proximate parts functionalitySources of Failure MechanismsNovember 3-4, 2015

RAM VIII Training Summit

4Slide5

Questions:What mechanism (Stress) caused the failure?

How can the failure occur?What could cause the part to fail?Why could the failure occur

?Are there possible system interactions, operating environments, customer usages that could cause the failure? Examples:Stresses acting upon the part/systemThermal ShockPhysical Shock

Heat/Cold Soak

Failure Mechanisms (Causes)

November 3-4, 2015

RAM VIII Training Summit

5Slide6

Questions:What are the results of the Failure Mechanism acting

upon the part?How did the part fail because of the failure mechanism? How could the part fail to perform its intended function? What

could go wrong with this part ? What has gone wrong with this part in the past? How could the part be abused or misused? What concerns do you have with this design/ part?

Examples:

Change in

shape

Strain, flexure, bending

Change

in

geometry

Crack initiation & propagation, fracture, wear-out, pitting, gallingChange in material

propertiesCorrosion, intermetallic compounds,

embrittlement, UV decay

Failure Modes (How)

November 3-4, 2015

RAM VIII Training Summit

6Slide7

Questions:What happens to the part with that failure mode?What happens to the system with that failure mode?

Examples:Part: Light doesn’t workSystem: Performs its intended function

Failure Effects (Results) November 3-4, 2015RAM VIII Training Summit

7Slide8

Part Nomenclature

Source of

Failure MechanismsFailure Mechanism

Failure Modes

Failure Effects

Part

Transportation

Storage

Operation

        Ambient          

FMEA Template

November 3-4, 2015

RAM VIII Training Summit

8Slide9

Reliability Block Diagram

Part 1

Part 2Part 3.1

Part 3.2

Part 4

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RAM VIII Training Summit

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Part 5

Part 6

Part 7Slide10

Part

Operating Condition

MTBF

Reliability

Year 1

Reliability

Year 3

Part 1

-

55

°

C

-

125

°

C

Part 2

-

60

°

C

-

105

°

C

Part 3.1

-

40

°

C

-

85

°

C

Part 3.2

-

40

°

C

-

85

°

C

Part 4

-55

°

C

-

150

°

C

Part 5

-65

°

C - 150

°

C

Part 6

-65

°C - 150°CPart 7-65°C - 150°C

Critical Items List

November 3-4, 2015

RAM VIII Training Summit

10Slide11

MTBF Determination MIL-HDBK 217

Results

Parameter

Value

λ

p

0.000001 Failures/10

6

 Hours

MTBF

7.759265e+11 hours

FIT

0.001289 Failures/10

9

 Hours

http://www.sqconline.com/military-handbook-mil-hdbk-217-beta

November 3-4, 2015

RAM VIII Training Summit

11Slide12

Reliability Equations

FIT – Failures per Billion hours

Reliability Equation

Failure Rate (

Landa

)

November 3-4, 2015

RAM VIII Training Summit

12Slide13

Part

Operating Range

FIT

MTBF (

Hrs

)

λ

1

3

5

Part 1

-

55

°

C

-

125

°

C

269.60

4.64E+05

2.16E-06

0.9813

0.9449

0.9098

Part 2

-

60

°

C

-

105

°

C

299.181.11E+068.98E-070.99220.97670.9614Part 3.1-40°

C

-

85

°

C

368.07

1.36E+06

7.36E-07

0.9936

0.9808

0.9683

Part 3.2

-

40

°

C

-

85

°

C

557.09

1.80E+06

5.57E-07

0.9951

0.98550.9759Part 4-55°C - 150°C685.377.30E+051.37E-060.98810.96460.9417Part 5-65°C - 150°C395.138.44E+051.19E-060.98970.9693

0.9494

Part 6

-65

°

C - 150

°

C

331.68

6.03E+05

1.66E-06

0.9856

0.9573

0.9299

Part 7

-

65

°

C

-

150

°

C408.051.23E+068.16E-070.99290.97880.9649

MTBF Determination

November 3-4, 2015

RAM VIII Training Summit

13Slide14

Operating ConditionsParts not rated for stated conditions of useLow MTBFComponents that are not redundant

Weak LinksNovember 3-4, 2015

RAM VIII Training Summit14Slide15

Heat / Cold

Vibration Thermal ShockPhysical ShockHumidity

CorrosionNovember 3-4, 2015RAM VIII Training Summit

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Testing

Failure

Mechanisms

Fatigue Testing -

Instron

HALT chamber

Thermal Shock

Cyclic Corrosion Chamber

Drop Test

Altitude Chamber

Dynamic Vibration System

Environmental Chamber

Equipment Used for TestingSlide16

# of

Failures

χ

2

T

n = 3

n = 5

n = 7

n = 10

n = 15

0

4.605

62170

863

518

370

259

173

1

7.779

105022

1459

875

625

438

292

2

10.645

143703

2994

1497

998

665

428

3

13.362

180381

7516

2505

1503

939

578

4

15.987

215827

4496

2248

1285

749

5

18.549

250416

10434

3478

1739

949

OC Curves

TABLE.OC Curves.θLCL = 27,000 hrs(3.080 years)α = 0.1for ConfidenceNovember 3-4, 2015RAM VIII Training Summit

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Number of Tests NeededSlide17

Questions

November 3-4, 2015RAM VIII Training Summit

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