MTEL Technology and Engineering

Correct Response: D. Metal fatigue is the failure of a metal part after repeated stress cycles. Metal fatigue is most likely to result when the direction of stress is reversed with each cycle. The most common example of this is when a metal part is bent back and forth. At a localized level, the two sides of the part are undergoing repeated cycles of tension followed by compression, and compression followed by tension, respectively. This is far more damaging to the part than repeatedly subjecting it to only tension (A), compression (B), or shear (C).