Design FPSO SMS for offshore 8-meter height wave Superflex TSB model has completed the design and produce GSB42080 Connect Head for (Floating Production Storage and Permanently Offloading offshore FPSO spread mooring systems). Superflex special offers FPSO TSB mooring systems with 50 years limited warranty.
Why and how the Superflex TSB420080, was able during storm turbulent still make the FPSO spread mooring systems line, with safe taut stiffness soft mooring systems landing, during the offshore 8-meter height wave shock force. The first Hydrostar Ariane analysis calculation report: as below pages.
Superflex Mooring Analysis Wave Load of FPSO
1) Calculation Theory
The FPSO hydrodynamic coefficients and wave exciting forces in incident harmonic waves are calculated by the commercial Hydrostar package, which is a standard 3D radiant-diffraction panel software for wave-body interactions, and the mooring load of lines are calculated by the commercial Ariane package developed by Bureau Veritas.
2) Calculation Conditions
2.1 Principle dimensions of FPSO
| Table.1 Principle Dimensions of FPSO | ||
|---|---|---|
| Unit | value | |
| Lpp | m | 300 |
| Breadth MLD | m | 75 |
| Depth MLD | m | 33 |
| Draught | m | 23.4 |
| Displacement | m3 | 427568 |
2.2 Hydrodynamic Coefficient of FPSO
1) Global axis system
Fig.1 Global Axis System
Where,
- C is the origin of the global axis system;
- CN is positive northward;
- CE is positive eastward;
- CZ is positive downwards;
- CNE is in the plane of the still water level.
Titanium TSB40080 Superflex Gr.5
Stainless Steel #316 fail
Titanium TSB40080 plate Superflex Gr.5 is O.K.
2) Meshing of FPSO
Fig.2 Meshing of FPSO
The numerical coordinate system of FPSO is set on the free surface, and the COG of FPSO in Global axis system is (1.7,0,-11.2)
2.2.1 First Order Excitaytion Load
Fig. 3 First Order Excitation Load of Fx
Fig. 4 First Order Excitation Load of Fy
Fig. 5 First Order Excitation Load of Fz
Fig. 6 First Order Excitation Load of Mx
Fig. 7 First Order Excitation Load of My
Fig. 8 First Order Excitation Load of Mz
2.2.2 Quadratic Transfer Function
Fig. 9 First Order Excitation Load of Fx
Fig. 10 Second-Order Difference-Frequency Load Fy
Fig. 11 Second-Order Difference-Frequency Load Fz
2.2.3 Mean Draft Load
Fig. 12 Mean Drift Load Fx
Fig. 13 Mean Drift Load Fy
2.2.4 Radiation Coefficient
Fig. 14 Add-Mass Coefficient (Surge-Surge\Sway-Sway\Heave-Heave)
Fig. 15 Add-Mass Coefficient (Roll-Roll\Pitch-Pitch\Yaw-Yaw)
Fig. 16 Radiation-Damping Coefficient (Surge-Surge\Sway-Sway\Heave-Heave)
Fig. 17 Radiation-Damping Coefficient (Roll-Roll\Pitch-Pitch\Yaw-Yaw)
3. FPSP Mooing Load Calculation
3.1 Different Load Condition as the List Below
| No. | Spectrum | Hs(m) | Tp | Wind(m/s) | Current(m/s) |
| Case1 | Jonswap | 6(Direction 175°) | 16.6 | 23.7(Direction 175°) | 2(Direction 180) |
| Case2 | Jonswap | 6(Direction 180°) | 16.6 | 23.7(Direction 180°) | 2(Direction 180) |
| Case3 | Jonswap | 6(Direction 210°) | 16.6 | 23.7(Direction 210°) | 2(Direction 180) |
| Case4 | Jonswap | 6(Direction 240°) | 16.6 | 23.7(Direction 240°) | 2(Direction 180) |
| Case5 | Jonswap | 6(Direction 175°) | 7.6 | 23.7(Direction 175°) | 2(Direction 180) |
| Case6 | Jonswap | 6(Direction 180°) | 7.6 | 23.7(Direction 180°) | 2(Direction 180) |
| Case7 | Jonswap | 6(Direction 210°) | 7.6 | 23.7(Direction 210°) | 2(Direction 180) |
| Case8 | Jonswap | 6(Direction 240°) | 7.6 | 23.7(Direction 240°) | 2(Direction 180) |
3.2 Mooring Design
3.2.1 Mooring Layout
3.2.2 Mooring Line Design
The Component number of the mooring lines
Design01: (Including Superflex Elastic Cable-SB35080)
The Component of mooring lines
| Name | No. | Material | Length (M) | Mass (kg/m) | MBL (KN) |
| Multiple Elastic Mooring | 01 | 132mm Studless R4k4 | 130 | 352 | 15964 |
| 02 | 110mm, Spiral Strand Wire Rope | 1550 | 63 | 10400 | |
| 03 | SUPERFLEX SB35080 | 8 | 40 | ||
| 04 | 122mm, Studless R4 | 142 | 301 | 13964 |
Design02: (Including Superflex Elastic Cable-SB40060)
The Component of mooring lines
| Name | No. | Material | Length (M) | Mass (kg/m) | MBL (KN) |
| Multiple Elastic Mooring | 01 | 132mm Studless R4k4 | 130 | 352 | 15964 |
| 02 | 110mm, Spiral Strand Wire Rope | 1550 | 63 | 10400 | |
| 03 | SUPERFLEX SB40060 | 6 | 40 | ||
| 04 | 122mm, Studless R4 | 142 | 301 | 13964 |
Design03: (Without Superflex Elastic Cable)
The Component of mooring lines
| Name | No. | Material | Length (M) | Mass (kg/m) | MBL (KN) |
| Multiple Elastic Mooring | 01 | 132mm Studless R4k4 | 130 | 352 | 15964 |
| 02 | 110mm, Spiral Strand Wire Rope | 1550 | 63 | 10400 | |
| 03 | 122mm, Studless R4 | 6 | 301 | 13964 | |
| 04 | 122mm, Studless R4 | 142 | 301 | 13964 |
Design04: (including Superflex Elastic Cable-SB40080)
The Component of mooring lines
| Name | No. | Material | Length (M) | Mass (kg/m) | MBL (KN) |
| Multiple Elastic Mooring | 01 | 132mm Studless R4k4 | 130 | 352 | 15964 |
| 02 | 110mm, Spiral Strand Wire Rope | 1550 | 63 | 10400 | |
| 03 | SUPERFLEX SB40080 | 8 | 40 | ||
| 04 | 122mm, Studless R4 | 142 | 301 | 13964 |
3.2.3 The curves of Two kinds of SUPERFLEX Elastic Cable Material
Fig. 18 The Curve of SUPERFLEX EC
The curves shows that the tension at different extension rate of one strand
3.3 The Layout Number of Mooring Lines
Fig. 19 Line Number From 1 to 12
3.4 Result No.1 (Wave Condition Hs=6, Ts=16.6)
| Design1 with Superflex (TSB35080) | Line No. | With Superflex TSB35080 Max Tension (KN) | Max Value | |||
| Case1(175°) | Cas2(180°) | Case3(210°) | Case4(240°) | |||
| Line 1 | 851 | 849 | 830 | 826 | 851 | |
| Line 2 | 856 | 854 | 834 | 825 | 856 | |
| Line 3 | 781 | 781 | 786 | 767 | 781 | |
| Line 4 | 908 | 914 | 968 | 1084 | 1084 | |
| Line 5 | 830 | 834 | 862 | 926 | 926 | |
| Line 6 | 851 | 856 | 904 | 989 | 989 | |
| Line 7 | 1164 | 1196 | 1398 | 1448 | 1448 | |
| Line 8 | 1106 | 1126 | 1235 | 1247 | 1247 | |
| Line 9 | 1225 | 1273 | 1607 | 1737 | 1737 | |
| Line 10 | 1052 | 1031 | 963 | 918 | 1052 | |
| Line 11 | 1361 | 1289 | 1107 | 1029 | 1361 | |
| Line 12 | 946 | 933 | 888 | 854 | 946 | |
| Design2 with Superflex (TSB40060) | Line No. | With Superflex TSB40060 Max Tension (KN) | Max Value | |||
| Case1(175°) | Cas2(180°) | Case3(210°) | Case4(240°) | |||
| Line 1 | 859 | 852 | 848 | 802 | 859 | |
| Line 2 | 864 | 858 | 851 | 830 | 864 | |
| Line 3 | 789 | 784 | 784 | 773 | 789 | |
| Line 4 | 914 | 916 | 975 | 1092 | 1092 | |
| Line 5 | 836 | 836 | 870 | 933 | 933 | |
| Line 6 | 856 | 860 | 910 | 995 | 995 | |
| Line 7 | 1177 | 1193 | 1418 | 1490 | 1490 | |
| Line 8 | 1116 | 1121 | 1258 | 1281 | 1281 | |
| Line 9 | 1241 | 1273 | 1617 | 1798 | 1798 | |
| Line 10 | 1058 | 1029 | 979 | 927 | 1058 | |
| Line 11 | 1133 | 1275 | 1139 | 1039 | 1275 | |
| Line 12 | 952 | 933 | 900 | 863 | 952 | |
3.5 Result No.2 (Wave condition Hs=6, Ts=7.6)
| Design1 With Superflex (TSB35080) | Line No. | With Superflex (TSB35080) Max Tension (KN) | |||
| Cas6(180°) | Case8(240°) | ||||
| Superflex EC | Superflex EC | ||||
| Line 1 | 834 | 782 | |||
| Line 2 | 840 | 774 | |||
| Line 3 | 769 | 742 | |||
| Line 4 | 914 | 2535 | |||
| Line 5 | 831 | 1579 | |||
| Line 6 | 857 | 2168 | |||
| Line 7 | 1266 | 2929 | |||
| Line 8 | 1183 | 2492 | |||
| Line 9 | 1355 | 3305 | |||
| Line 10 | 1056 | 815 | |||
| Line 11 | 1362 | 872 | |||
| Line 12 | 951 | 784 | |||
| Design2 with Superflex (TSB40060) | Line No. | With Superflex TSB40060 Max Tension (KN) | |||
| Cas6(180°) | Case8(240°) | ||||
| Line 1 | 851 | 794 | |||
| Line 2 | 855 | 783 | |||
| Line 3 | 783 | 754 | |||
| Line 4 | 926 | 1939 | |||
| Line 5 | 842 | 1765 | |||
| Line 6 | 866 | 2413 | |||
| Line 7 | 1245 | 3055 | |||
| Line 8 | 1164 | 2559 | |||
| Line 9 | 1335 | 3484 | |||
| Line 10 | 1062 | 825 | |||
| Line 11 | 1377 | 884 | |||
| Line 12 | 954 | 792 | |||
| Design3 (Without SUPERFLEX) | Line No. | Without Superflex Max Tension (KN) | |||
| Cas6(180°) | Case8(240°) | ||||
| Line 1 | 868 | 834 | |||
| Line 2 | 873 | 823 | |||
| Line 3 | 802 | 786 | |||
| Line 4 | 945 | 10421 | |||
| Line 5 | 860 | 1332 | |||
| Line 6 | 886 | 1754 | |||
| Line 7 | 1285 | 2238 | |||
| Line 8 | 1201 | 1493 | |||
| Line 9 | 1375 | 13299 | |||
| Line 10 | 1083 | 879 | |||
| Line 11 | 1405 | 958 | |||
| Line 12 | 973 | 833 | |||
| Design4 With Superflex (TSB40080) | Line No. | With Superflex (TSB40080) Max Tension (KN) | |||
| Cas6(180°) | Case8(240°) | ||||
| Superflex EC | Superflex EC | ||||
| Line 1 | 843 | 796 | |||
| Line 2 | 856 | 785 | |||
| Line 3 | 776 | 754 | |||
| Line 4 | 914 | 2021 | |||
| Line 5 | 858 | 1551 | |||
| Line 6 | 872 | 2226 | |||
| Line 7 | 1193 | 3009 | |||
| Line 8 | 1102 | 2631 | |||
| Line 9 | 1257 | 3421 | |||
| Line 10 | 1093 | 821 | |||
| Line 11 | 1289 | 894 | |||
| Line 12 | 951 | 747 | |||
3.6 Conclusion: (Green marks stand safe, Yellow marks stand dangerous)
1. Under wave condition (H5=6, T5=16.6)
The case01--04 shows that the mooring line Load is very small.
2. Under wave condition (H5=6, T5=7.6)
The case06 and case 08 is the two remarkable case shall be listed which we get that during the computer progress. And the case08 is the most dangerous case.
- Considering result No.2, we can know that the design-03(without SUPERFLEX) would lead the mooring lines to be broken up under case08.
- Considering result No.2 we can know that the design 01, design 02, design 04 (with SUPERFLEX EX) could make the mooring lines be safety.
- Under case 08 which is most condition, the SUPERFLEX EC can make the mooring Max Load be less than 3500 KN which make the mooring lines under the safe.
- At the Max load <3500 KN. the SUPERFLEX EC extension rate is less than 75% according to the curve EC.