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DNV RP C203 Stress Components

Note

This code check complies with Det Norske Veritas Recommended Practice RP-C203 "Fatigue Design of Offshore Steel Structures", April 2008 Ed.

Results variables grouped within DNV RP-C203 include the following :

  • Hoop stress, calculated according to DNV RP-C203

  • Axial stress, calculated according to DNV RP-C203

  • Combined Von Mises stress, calculated according to DNV RP-C203

Values presented in the GUI are actually stress components values which are to be compared to the design criteria as listed below.

Hoop stress criterion

The hoop stress is

To comply with DNV RP-C203 requirement, the hoop stress σh shall be limited to :

σh ≤ ηs SMYS

where :

  • σh = Hoop stress

  • ηs = Usage factor for pressure containment (DNV C204 Table C1) = 0.83 for operating conditions

  • SMYS = Specified Minimum Yield Stress

Axial stress criterion

To comply with DNV 96 requirement C400, the axial stress σL shall be limited to :

σL ≤ η SMYS

where :

  • σL = Longitudinal stress = σ1 +/- (σB + σb)

  • η = Usage factor for equivalent stress check = 0.96 (DNV Table C4)

  • σ1 = Longitudinal stress due to pressure end cap effect

  • σB = Bending stress due to other loads than expansion

  • σb = Resultant bending stress due to expansion loads

  • SMYS = Specified Minimum Yield Stress

Combined Von Mises stress criterion

To comply with DNV 96 requirement C 400, the Von Mises combined equivalent stress σe shall be limited to :

σe ≤ η SMYS

where :

  • σe = Von Mises combined stress = [σh - (σL σh) + σL + 3 τ ]1/2

  • η = Usage factor for equivalent stress check = 0.96 (DNV Table C4)

  • σh = Hoop stress (section 3.3.1)

  • σL = Longitudinal stress (section 3.3.2)

  • τ = Tangential shear stress. τ = max i<r<e{(Pi-Pe).Si.Se/(S.Sr)} = (Pi-Pe)Se/S

  • SMYS = Specified Minimum Yield Stress