CQE Reliability and Risk Management 2 — Questions and Answers
Question 1: In FMEA, which action would most effectively reduce a high Severity rating?
- Improving detection controls
- Reducing the occurrence of the failure cause
- Redesigning the product or process to eliminate or mitigate the failure effect (Correct answer)
- Increasing inspection frequency
Correct answer: Redesigning the product or process to eliminate or mitigate the failure effect
Severity ratings can only be reduced by redesigning the product or process to change or eliminate the failure mode's effect on the customer, as severity reflects the inherent consequence of the failure.
Question 2: Weibull analysis is used in reliability engineering primarily to:
- Model defect distribution in production
- Characterize failure time distributions and identify failure modes (Correct answer)
- Calculate process capability indices
- Determine sample sizes for acceptance sampling
Correct answer: Characterize failure time distributions and identify failure modes
Weibull analysis fits failure time data to the flexible Weibull distribution, whose shape parameter (beta) identifies whether failures are due to infant mortality (β<1), random (β=1), or wear-out (β>1) modes.
Question 3: What is meant by 'design redundancy' as a reliability strategy?
- Eliminating unnecessary design features
- Providing backup components or systems so the system functions if one component fails (Correct answer)
- Reducing the number of parts in an assembly
- Reusing proven designs without modification
Correct answer: Providing backup components or systems so the system functions if one component fails
Design redundancy improves reliability by incorporating parallel components or subsystems that can take over function if a primary component fails, preventing system-level failure.
Question 4: In risk management, what does a risk matrix primarily help determine?
- The financial cost of each risk
- The priority of risks based on likelihood and severity for mitigation planning (Correct answer)
- The schedule for risk reviews
- The number of auditors needed
Correct answer: The priority of risks based on likelihood and severity for mitigation planning
A risk matrix plots risks on a grid of likelihood versus severity, helping teams prioritize which risks require immediate mitigation versus monitoring versus acceptance.
Question 5: Failure Mode, Effects, and Criticality Analysis (FMECA) extends FMEA by adding:
- Customer feedback data
- A criticality analysis that quantifies the probability and severity of each failure mode (Correct answer)
- Real-time monitoring requirements
- Supplier qualification criteria
Correct answer: A criticality analysis that quantifies the probability and severity of each failure mode
FMECA adds a criticality analysis to FMEA, using failure rate data and mission time to mathematically quantify each failure mode's criticality, enabling more rigorous prioritization.
Question 6: Which reliability growth model is commonly used to track and predict reliability improvement during development testing?
- Pareto model
- Duane/AMSAA model (Correct answer)
- Weibull model
- Poisson model
Correct answer: Duane/AMSAA model
The Duane/AMSAA (Army Materiel Systems Analysis Activity) model tracks cumulative test time and failures to project reliability growth and forecast when reliability targets will be achieved.
CQE Reliability and Risk Management 2
In FMEA, which action would most effectively reduce a high Severity rating?