Calculate general shape factor and accumulated fatigue damage from stress return period data using the simplified method (DNVGL-RP-C203 section 5.1).
Enter stress values as comma or tab separated sets (return period, stress amplitude, period), with each set on a new line. The stress amplitude is assumed to follow a two parameter Weibull distribution.
Maximum stress amplitude values should be calculated from return period loads (eg 10 year load, 20 year load, 50 year load etc...). The zero upcrossing period is calculated from the mean of the upcrossing period data. The shape factor is calculated from the slope of the Weibull stress regression. The maximum stress amplitude is calculated from the design life (the return period is assumed to be equal to the design life).
Tool Input
- ptype : Plot Scale Type
- sptype : Sample Period Type For Zero Upcrossing Period Data
- SPu : User Defined Wave Sample Period
- jointtype : Joint Or Material Type
- csntype : SN Curve Type
- walltype : Weld Joint Type
- tru : User Defined Reference Thickness
- kfactype : Thickness Exponent Type
- ku : User Defined Thickness Exponent
- scftype : Stress Concentration Factor Type
- SCFu : User Defined Stress Concentration Factor
- dfftype : Design Fatigue Factor Type
- DFFu : User Defined Design Fatigue Factor
- ratype : Forging Surface Roughness Type
- temptype : Temperature Derating Type
- Tdu : User Defined Design Temperature
- systype : System Effect Factor Type
- Rsu : User Defined System Effect Log Factor
- hfactype : Shape Factor Type
- hu : User Defined Shape Factor
- sstype : Maximum Stress Type
- Su : User Defined Stress Amplitude
- tztype : Zero Upcrossing Period Type
- Tzu : User Defined Zero Upcrossing Period
- Rdata : Return Period Data
- Sdata : Stress Data Points
- Tdata : Wave Period Data Points
- R : Return Period
- tn : Wall Thickness
Tool Output
- D : Accumulated Fatigue Damage
- DFF : Design Fatigue Factor
- N : Number Of Cycles In Design Life
- Rm : Material Thickness Derating Log Factor
- Rs : System Effect Log Factor
- Rt : Temperature Derating Log Factor
- SCF : Stress Concentration Factor
- Sd : Design Stress Amplitude (With SCF)
- Sn : Nominal Stress Amplitude (Without SCF)
- Sr : Return Period Stress (With SCF)
- Tr : Return Period Zero Upcrossing Period
- Tz : Zero Upcrossing Period
- h : Weibull Shape Parameter
- k : Thickness Exponent
- sps : Sample Period For Stress Amplitude Data
- spt : Sample Period For Upcrossing Period Data
- tref : Reference Thickness