Design for Reliability Flashcards
7 cards from real CRE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Design for Reliability flashcards as text
What is the primary purpose of derating in Design for Reliability?
Answer: To operate components below their maximum rated stress levels to extend life
Derating operates components below their maximum rated stress levels, reducing failure rates and extending operational life.
Which type of redundancy involves switching to a backup component only when the primary fails?
Answer: Passive (cold) standby redundancy
Passive (cold) standby redundancy keeps the backup component unpowered or inactive until the primary fails, reducing wear on the standby unit.
In a Reliability Block Diagram (RBD), components arranged in series will result in a system reliability that is:
Answer: Less than or equal to the lowest individual component reliability
In a series configuration, system reliability is the product of all component reliabilities, making it always less than or equal to the least reliable component.
Which Design FMEA output metric prioritizes failure modes by combining severity, occurrence, and detection ratings?
Answer: Risk Priority Number (RPN)
The Risk Priority Number (RPN) = Severity × Occurrence × Detection, and is used in FMEA to rank failure modes and prioritize corrective actions.
What is the main goal of a Design Review for Reliability (DRR)?
Answer: To verify that reliability requirements are addressed and risks identified before design is frozen
A Design Review for Reliability ensures that reliability requirements are incorporated and potential risks are identified and mitigated before the design is committed to production.
In the context of Design for Reliability, what does 'physics of failure' (PoF) approach emphasize?
Answer: Understanding the physical mechanisms and root causes that drive component degradation and failure
The physics of failure approach focuses on understanding the underlying physical, chemical, and mechanical mechanisms that cause failures, enabling proactive design improvements.
What is a 'single point of failure' (SPOF) in a system design?
Answer: A component or subsystem whose failure alone causes the entire system to fail
A single point of failure is any element whose failure results in complete system failure, making it a critical reliability risk that typically requires redundancy or redesign.