Dnv Verification
6
Riser Design Based On − − DNV OS F201 Maximum water depth; ≔ h 3000 m Riser nominal outside diameter ≔ D 12 in Density_of_seawater; ≔ ρ seawater 1025 ―― kg m 3 (Steel properties) − X 65 yield ≔ SMYS 448 MPa tensile_strength ≔ SMTS 530 MPa Ovality; ≔ f 0 = % 0.3 0.003 Density of steel; ≔ ρ s 8050 ―― kg m 3 Riser Content Density of riser content; ≔ ρ i 835 ―― kg m 3 Design Pressure ≔ P d = 12000 psi 82.737 MPa Maximum Temperature ≔ T max 80 °C DETERMINATION_OF_PRESSURE_LOADS External_pressure; ≔ P e = ⋅ ⋅ ρ seawater g h 30.155 MPa Sec.3, B100Table 3-2 gives the incidental to design pressure ratios For a typical Export/Import Riser is 1.1 ≔ P inc = ⋅ 1.1 P d 91.011 MPa The local internal design pressure pld and local incidental pressure pli are determined based on the definitions given in B 100 as follows: ≔ P ld = + P d ⋅ ⋅ ρ i g h 107.303 MPa ≔ P li = + P inc ⋅ ⋅ ρ i g h 115.576 MPa RESISTANCE_FACTORS γ m; γ SC are the material resistance factor and safety class resistance factor obtained from Sec. C102, Table 5-4 and Table5-3 respectively ≔ γ m 1.15 ≔ γ SC 1.14
-
Upload
okpokparoro -
Category
Documents
-
view
6 -
download
1
description
Riser Design Verification Example
Transcript of Dnv Verification
-
Riser Design Based On DNV OS F201
Maximumwater depth; h 3000 mRiser nominal outside diameter D 12 in
Density_of_seawater; seawater 1025 kg
m3
(Steel properties)X 65
yield SMYS 448 MPatensile_strength SMTS 530 MPa
Ovality; f0 =%0.3 0.003
Density of steel; s 8050 kg
m3
Riser ContentDensity of riser content; i 835
kg
m3
Design Pressure Pd =12000 psi 82.737 MPaMaximumTemperature Tmax 80 C
DETERMINATION_OF_PRESSURE_LOADS
External_pressure; Pe =seawater g h 30.155 MPa
Sec.3, B100Table 3-2 gives the incidental to design pressure ratiosFor a typical Export/Import Riser is 1.1
Pinc =1.1 Pd 91.011 MPa
The local internal design pressure pld and local incidental pressure pli are determined based on the definitions given in B 100 as follows:
Pld =+Pd i g h 107.303 MPaPli =+Pinc i g h 115.576 MPa
RESISTANCE_FACTORS
m; SC are the material resistance factor and safety class resistance factor obtained from Sec. C102, Table 5-4 and Table5-3 respectively
m 1.15 SC 1.14
-
MATERIAL_FACTORS
Sec.5 C300:
fy;temp :the de-rating values due to the temperature of the yield stress
:the de-rating values due to the temperature of tensile strength
fu;temp
From the figure on the right based on Sect.5 C303, the de-rating effects at 80 deg Centigrade are 20MPa each
fy;temp 20 MPa
fu;temp 20 MPa
Material Strength factor; U 0.96 (Sec.5 C304, Table5-6)
Maximum facbrication factor for UOE; fab 0.85 (Sec.5 C305, Table5-7)
Yieldstress to be used in the design;
fy = SMYS fy;temp U 410.88 MPa
Tensile strength to be used in the design;
fu = SMTS fu;temp U 489.6 MPa
-
WALL_THICKNESS
Sec.5, D203: The minimum required wall thickness for a straight pipe without allowances and tolerances is given by:
t1 D
+4
3
minfy;
fu
1.15
m SC Pli Pe1
=fy 410.88 MPa
=fu
1.15425.739 MPa
t1 =D
+4
3
fy
m SC Pli Pe1
1.267 in
Corrosion allowance; tcorr 5 mmTolerance =%10 0.1
Nominal wall thickness ((uncorroded)) ; tnom = +t1 tcorr
(( 1 Tolerance))1.626 in
PRESSURE_CONTAINMENT ((BURSTING)) (Sec.5 D200)
The pressure containment shall fufil the following criterion:
Pli PePb t1
m SC
The_Pressure_containment_resistance; Pb ((t)) 2 t
D tfcb
2
23
((Eq.5.8))
For_calculating Pb ((t)) ; fcb Minfy ;
fu
1.15
=fy 410.88 MPa =fu
1.15425.739 MPa
fcb 410.88 MPat =t1 32.175 mm
Pb =2 t
D tfcb
2
23
111.987 MPa
=Pli Pe 85.421 MPa =
Pb
m SC
85.421 MPa THE CRITERION SATISFIED
-
SYSTEM_HOOP_BUCKLING ((SYSTEM_COLLAPSE_CHECK)) ((Sec.5_D300))
The external pressure at any point along the pipeline shall fulfil the following criterion:
Pe Pmin Pc t1
m SC
Pmin is the minimum internal pressure taken as zero for empty riser
Thus; Pe Pc t1
m SC
Pc The characteristic resistance for external pressure (hoop buckling) shall be calculated thus:
Pc ((t)) Pel ((t)) Pc ((t))
2Pp ((t))
2 Pc ((t)) Pel ((t)) Pp ((t)) f0
D
t
Where;
E 2.1 1011Pa v 0.3 t =t1 32.175 mm
Pel =
2 Et
D
3
1 v2
542.899 MPa The elastic collapse pressure (instability)
Pp =fy fab 2 t
D73.734 MPa The plastic collapse pressure
=f0 0.003Solving_for_Pc;
Pc Pel Pc
2Pp
2 Pc Pel Pp f0 D
t
Pc 542.899 Pc
273.734
2 Pc 542.899 73.734 f0 D
t
Pc 1
Pc 542.899 Pc
273.734
2 Pc 542.899 73.734 f0 D
t
Pc. =Find Pc 72.535
-
Pc =Pc. 1 MPa 72.535 MPa
=Pe 30.155 MPa =Pc
m SC55.328 MPa
THE CRITERION SATISFIED
PROPAGATING_BUCKLING ((Sec.5_D400))
The propagating buckle criterion is given by:
Pe Pmin Ppr
c m SCc 1
Pmin 0t2 =tnom tcorr 36.306 mm
The_Resistance_against_propagating_buckling;
Ppr =35 fy fabt2
D
2.5
59.855 MPa
=Pe 30.155 MPa =Ppr
c m SC45.656 MPa
THE CRITERION SATISFIED
Combined Loading Criteria: Sec.5 D 500 Pipe members subjected to bending moment, effective tension and net internal overpressure shall be designed to satisfy the following equation:
+ SC m
+
||Md||
Mk
1
Pld PcPb
2
Ted
Tk
2
Pld PcPb
2
1 `
Design Bending Moment Md 2000 N m
-
Design Effective Tension Ted 5000 N
Local internal design Pressure =Pld 107.303 MPa
External Pressure =Pe 30.155 MPa
c is a parameter accounting for strain hardening andwall thinning given by:
c +(( 1 )) fu
fy +0.4 qh for
