Practice Test Geeks(CRE) Certified Reliability Engineer Practice Test
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Reliability Fundamentals 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 Reliability Fundamentals flashcards as text

  1. A non-repairable component has a Weibull distribution with β = 2.5 and η = 1000 hours. What does η represent?

    Answer: The characteristic life at which 63.2% of units have failed

    The Weibull scale parameter η (characteristic life) is the time at which 63.2% of units will have failed, regardless of β.

  2. Which of the following is the correct formula for the reliability of a two-component active parallel system?

    Answer: R_sys = 1 - (1 - R₁)(1 - R₂)

    For an active parallel system, the system fails only if all components fail: R_sys = 1 - (1-R₁)(1-R₂).

  3. The B10 life of a bearing is the time by which what percentage of bearings will have failed?

    Answer: 10%

    BX life is the time by which X% of a population will have failed, so B10 life corresponds to 10% failure.

  4. A system's hazard function h(t) is constant. What does this imply about its failure behavior?

    Answer: Failures are memoryless and occur randomly

    A constant hazard rate implies the exponential distribution and memoryless property — past operation does not affect future failure probability.

  5. What is the primary purpose of accelerated life testing (ALT) in reliability engineering?

    Answer: To precipitate failures quickly by applying elevated stress to estimate normal-use life

    ALT applies stresses above normal use levels to induce failures faster, then uses models to extrapolate life at normal conditions.

  6. Which of the following correctly distinguishes MTTF from MTBF?

    Answer: MTTF applies to non-repairable items; MTBF applies to repairable systems

    MTTF (Mean Time To Failure) is used for non-repairable items; MTBF (Mean Time Between Failures) applies to repairable systems.

  7. In a reliability context, what does 'inherent availability' exclude that 'operational availability' includes?

    Answer: Inherent availability excludes logistics and administrative downtime; operational availability includes them

    Inherent availability (Ai = MTBF/(MTBF+MTTR)) only considers active repair time, while operational availability adds logistics and administrative delay.