Understanding Fatigue Failure: Causes, Risks & Prevention

Fatigue Failure

Fatigue failure is the failure of a material due to repeated cyclic loading/unloading. It occurs at stress levels significantly lower than the material's yield strength.

Mechanism

Microscopic cracks initiate at stress concentrators (notches, surface defects), propagate with each cycle, and eventually cause sudden fracture.

Common Examples

• Aircraft wings
• Bridges
• Car springs and suspension components
• Rotating machinery shafts

Prevention

• Design to minimize stress concentrations
• Surface treatments (shot peening, polishing)
• Material selection (high fatigue strength)
• Regular inspection and maintenance
• Load monitoring and spectrum analysis