DNV RP-C203 (2024)

DNV RP-C203 (2024) defines fatigue assessment procedures for welded and non-welded offshore steel structures. SDC Verifier implements the standard per the 2024 edition, using Method B (Chapter 4.8) for stress extraction and applying environment-specific rules from Chapters 2.4.4 (air) and 2.4.5 (seawater with cathodic protection).

Key Fatigue Parameters:

• Environment Type: Air by default; seawater CP configurable
• Hot Spot Stress: Offset at 0.5t from weld toe or shell intersection
• SN Curve Assignment:
  • Global SN curve for non-welded components
  • Directional SN curves (X = parallel, Y = perpendicular) for welds
  • Weld intersections: automatically assign lowest fatigue class
  • Angular stress interpolation via Table F-1 (Appendix F.5)

Thickness Factor: Reference thickness = 25 mm (non-tubular), 16 mm (tubular). Thickness exponent K as per Tables 2-1 to 2-4. Can be edited per weld group or element type.

Stress Factor: By default, a 1.12 hot spot amplification factor is applied (can be disabled).

Other Features:

• C2* curve override for user-defined fatigue curves
• Method B valid for both shell and solid models
• Uses fatigue life estimation with SN curves (stress-life method)
• Supports carbon-manganese steel with yield strength < 960 MPa

This standard is essential for verifying welded joints and critical details in offshore topsides, jackets, marine terminals, wind turbine foundations, and similar cyclically loaded structures.