Exam Question

### Causes of Fatigue Cracking in Engineering Components
Fatigue is the progressive and localized structural damage that occurs when a material is subjected to repeated or fluctuating (cyclic) stresses. The failure can occur at a stress level significantly lower than the material's Ultimate Tensile Strength (UTS) or even its yield strength. The process is insidious as it often occurs without any obvious prior warning or significant plastic deformation before failure.
The primary causes are:
1. **Cyclic Loading**: The application of a fluctuating stress or strain is the fundamental requirement for fatigue. This can be alternating (tension-compression), repeated (zero to tension), or random.