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
Galvanic corrosion between dissimilar metals is most accelerated when:
Answer: The anode area is small relative to the cathode area
A small anode coupled to a large cathode creates a highly unfavorable area ratio, concentrating corrosion attack on the smaller anode and accelerating its degradation.
In reliability testing, the term 'censored data' (or suspended data) refers to:
Answer: Units that were removed from the test before failing
Censored (suspended) data represents test units that were removed or ended the test without experiencing a failure, providing partial life information.
Which type of fatigue failure is characterized by striations visible under electron microscopy and typically shows no macroscopic plastic deformation?
Answer: High-cycle fatigue
High-cycle fatigue occurs at stress levels below yield strength, producing characteristic microscopic striations and very little plastic deformation at the macroscopic level.
The Coffin-Manson relationship in low-cycle fatigue relates the number of cycles to failure to:
Answer: Plastic strain amplitude
The Coffin-Manson relationship states that plastic strain amplitude is inversely related to the number of cycles to failure, governing low-cycle fatigue behavior.
A product passes HASS (Highly Accelerated Stress Screen) but still exhibits early field failures. The most likely explanation is:
Answer: The dominant failure mode in the field was not precipitated by the HASS stresses applied
If HASS stresses do not replicate the failure mechanism occurring in the field, the screen cannot detect or precipitate that failure mode.
In a fishbone (Ishikawa) diagram, the 6M categories used to organize potential causes include all of the following EXCEPT:
Answer: Money
The traditional 6M categories are Man, Machine, Method, Material, Measurement, and Mother Nature (Environment) — 'Money' is not a standard category.
Hydrogen embrittlement in high-strength steel is most likely to cause failure under which loading condition?
Answer: Sustained tensile stress
Hydrogen embrittlement typically causes delayed fracture under sustained tensile stress as hydrogen diffuses to high-stress regions and reduces ductility.