Failure Analysis & Testing 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 Failure Analysis & Testing flashcards as text
A Weibull plot of field failure data shows a shape parameter (β) of 0.5. This indicates the failures are most likely due to:
Answer: Infant mortality or early-life failures
A Weibull shape parameter β < 1 indicates a decreasing failure rate, characteristic of infant mortality failures caused by latent defects.
In failure mode and effects analysis (FMEA), the Risk Priority Number (RPN) is calculated as:
Answer: Severity × Occurrence × Detection
RPN = Severity × Occurrence × Detection, where each factor is rated on a scale (typically 1–10) to prioritize corrective actions.
Which failure analysis method uses dye to reveal cracks and surface discontinuities in non-porous materials?
Answer: Liquid penetrant testing
Liquid penetrant testing (PT) uses capillary action to draw dye into surface-breaking discontinuities, which is then revealed with a developer.
The Inverse Power Law model in accelerated testing is typically applied when the accelerating stress is:
Answer: Voltage or mechanical load
The Inverse Power Law relates life to non-thermal stresses such as voltage, pressure, or mechanical load, where life is inversely proportional to stress raised to a power.
During failure investigation, a 'witness mark' on a bearing component most likely indicates:
Answer: Contact or impact with another component during operation
Witness marks are impressions or rub marks left on a surface by contact with another component, indicating improper clearance or misalignment.
In a step-stress accelerated life test, stresses are:
Answer: Increased incrementally at fixed time intervals
In step-stress ALT, the stress level is increased at predetermined intervals, allowing failures to be induced faster while still providing life-stress data.
What is the primary goal of a corrective action verification in the failure analysis process?
Answer: To confirm the corrective action eliminates the root cause without introducing new failures
Corrective action verification confirms that the implemented fix actually prevents recurrence of the failure mode while not creating unintended side effects.