Applies To
Product(s):	AutoPIPE
Version(s):	ALL;
Area:	Stress Calculations
Date Logged & Current Version	April 2023 23.00.00.230

Problem:

How does AutoPIPE calculate DNVGL-F101 offshore 2017 ASD (Allowable Stress Design Check) code calculations so that Equivalent stress (Von Mises) (Eq. 5.46) = 87.99 N/mm^2 (as shown below) at node point A04?

Solution:

Given the following information about the system

D = 355.6 mm "Pipe outside dia"

t = 34.8 mm "pipe wall thickness"

P = 22 MPa "Internal Operating Pressure"

Fa = 0 N "Axial force from Code Compliance results, GrT1P1"

N*m "Local Bending Moments from Code Compliance results, GrP1T1"

f_LongP = 1 "Results model Option, Longitudinal Pressure, set to 1 when P, set to 0 when A

Calculations:

Metal Area of Pipe

A = 35070 mm²

Pressure Area (Pipe ID)

Ap = 64240 mm²

Moment Section Modulus

ZM = 2567000 mm³

Bending Stress

σB = 0 MPa

Long Pressure Stress ( N )

N_AP = 56.201 MPa

Hoop Stress (Eq. 5.47)

σh = 101.402 MPa

Longitudinal/Axial stress (Eq. 5.48)

σ_Lmax = 56.201 MPa

Equivalent stress (Von Mises) (Eq. 5.46)

σ_{e_max} = 87.989 MPa

σ_{e_min} = 87.989 MPa

Values agree with that reported in Results:

Allowable

η x f_Y =

η = 0.8 ASD Usage factor - Usage factor for equivalent stress check (table 5-14, low=1.0, medium=0.90, high=0.80)

f_Y = (SMYS - F y,temp) αu Code Eq (5.4)

f_Y = 450 MPa - SMYS - Yield strength at room or temperature, psi (defined on pipe properties) dependent on load/displacement de-rating factor

αu = 0.96 - Material strength factor, se table 5-3

Fy,temp = 34 MPa Temperature Derating Factor - the derating values due to the temperature of the yeild stress and the tensile strength respectively see (5.3.3.4), Find on Press/Temp/PipeId tab of the input grids

Allowable = 319.488 MPa

15. How are DNVGL-F101 offshore 2017 ASD calculations per GrT1P1 performed in AutoPIPE?

Problem:

Solution:

Calculations:

See Also