Which is NOT listed as a common cause of Distortion Induced Fatigue?

• A. Web Gap Details
• B. Corrosion
• C. Skewed bridges
• D. Lateral Bracing

Answer: (B)

Distortion Induced Fatigue comes from geometric distortion and assembly details that create local stress concentrations and bending under cyclic loading. The typical culprits are features that promote distortion during fabrication or during service: web gap details can cause sharp distortions at the connection, skewed bridges introduce angular misalignment that increases out‑of‑plane distortion, and insufficient lateral bracing lets members deflect and distort under repeated loading, concentrating strain in critical areas. Corrosion, while it can accelerate crack growth by reducing cross‑section and opening cracks, is not a distortion‑driven mechanism. It affects fatigue more generally rather than creating the distortion patterns that DIF relies on. So corrosion is not listed as a common cause of Distortion Induced Fatigue.