🔍 Key Concepts

• Endurance limit of a material and what happens when it is exceeded under repeated loading • Different types of gear tooth surface damage: initial (corrective) pitting, destructive pitting, and spalling • How fatigue failure shows up on gear tooth surfaces over time

💭 Think About

• Think about which listed damage types are specifically related to fatigue from repeated stress cycles rather than a single overload event. • Ask yourself: as the surface is stressed over and over past its endurance limit, does the damage usually begin small and progress, or appear all at once in a completely different form? • Compare how each option might fit into an overall progression of damage on a gear tooth surface as the fatigue gets worse.

✅ Before You Answer

• Make sure you can define the difference between initial (corrective) pitting and destructive pitting. • Verify what spalling looks like on a gear tooth surface and whether it is considered a fatigue-related surface failure. • Before choosing "All of the above," confirm that each individual type listed can correctly be described as caused by exceeding the endurance limit of the surface material.