Daniel Sillivant University of Alabama in Huntsville Daniel.Sillivant@UAH

1. Daniel Sillivant University of Alabama in Huntsville Daniel.Sillivant@UAH.edu Using FMEA to Address Warranty Duration

2. Outline • FMEA Process • Reliability Block Diagrams • Critical Items List • MTBF and Reliability Calculations • OC Curve for Number of Tests • Warranty Decisions RAM VIII Training Summit

3. Failure Mode and Effect Analysis ( FMEA) FMEA: Methodology designed to identify potential failure modes • Basic Procedure: • Identify the item(s) to be analyzed • Identify the • Function(s), • Failure Mechanism(s) (Cause) • Failure Mode(s) (How) • Failure Effect(s) (Results) • Evaluate the issues identified by the analysis • Additional Tools • Critical Items List (CIL) • Reliability Block Diagram (RBD) • Reliability Calculations • Warranty Confidence - OC Curves • Physical Testing RAM VIII Training Summit

4. Sources of Failure Mechanisms • Transportation • Packing • Handling at each stage of shipment from origin to end user • Truck, Rail, Aviation & Sea • Storage • Distribution chain • At end user • Operational conditions of use (intrinsic) • Result from system function • Ambient conditions of use (extrinsic) • Result from environmental exposure and from proximate parts functionality RAM VIII Training Summit

5. Failure Mechanisms (Causes) 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/system • Thermal Shock • Physical Shock • Heat/Cold Soak RAM VIII Training Summit

6. Failure Modes (How) 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, galling • Change in material properties • Corrosion, intermetallic compounds, embrittlement, UV decay RAM VIII Training Summit

7. Failure Effects (Results) Questions: • What happens to the part with that failure mode? • What happens to the system with that failure mode? Examples: • Part: Light doesn’t work • System: Performs its intended function RAM VIII Training Summit

8. FMEA Template RAM VIII Training Summit

9. Reliability Block Diagram Part 3.1 Part 1 Part 2 Part 4 Part 3.2 Part 5 Part 6 Part 7 RAM VIII Training Summit

10. Critical Items List RAM VIII Training Summit

11. MTBF Determination MIL-HDBK 217 • http://www.sqconline.com/military-handbook-mil-hdbk-217-beta RAM VIII Training Summit

12. Reliability Equations FIT – Failures per Billion hours Failure Rate (Landa) Reliability Equation RAM VIII Training Summit

13. MTBF Determination RAM VIII Training Summit

14. Weak Links • Operating Conditions • Parts not rated for stated conditions of use • Low MTBF • Components that are not redundant RAM VIII Training Summit

15. Testing • Heat / Cold • Vibration • Thermal Shock • Physical Shock • Humidity • Corrosion Failure Mechanisms Equipment Used for Testing • Fatigue Testing - Instron • HALT chamber • Thermal Shock • Cyclic Corrosion Chamber • Drop Test • Altitude Chamber • Dynamic Vibration System • Environmental Chamber RAM VIII Training Summit

16. OC Curves Number of Tests Needed RAM VIII Training Summit

17. Questions RAM VIII Training Summit