Sub-skill of fe-analyst: Environmental Load Summary (+1).
Loads:
├── Gravity
│ └── g = 9.81 m/s²; direction: −Z (downward)
│
├── Hydrodynamic (Morison Equation)
│ ├── Drag coefficient Cd (normal) — API RP 2RD typical: 1.0−1.2
│ ├── Inertia coefficient Cm = 1 + Ca — typical Ca = 1.0
│ ├── Lift coefficient Cl (VIV suppression: 0.0 without analysis)
│ └── Added mass coefficient Ca (transverse and axial)
│
├── Wave Loading
│ ├── Wave theory: Airy (linear), Stokes 5th, Dean Stream
│ ├── Sea state: Hs [m], Tp [s], γ (JONSWAP peak factor)
│ ├── Heading: θ_wave [° from North or from vessel heading]
│ └── Direction spread: long-crested or short-crested
│
├── Current
│ ├── Profile: u(z) vs. depth [m/s at each depth]
│ ├── Heading: θ_current [°]
│ └── Type: Gulf Stream, tidal, mean loop current
│
├── Wind (for surface-piercing structures)
│ ├── Speed: U10 [m/s] (10-min mean at 10m elevation)
│ ├── Heading: θ_wind [°]
│ └── Applicable: turret mooring, topsides drag
│
└── Functional Loads
├── Internal pressure: Pi [MPa] (operating vs. design)
├── Temperature: T [°C] (thermal expansion driving force)
├── Lay tension: Th [kN] (installation)
└── Pre-tension: T_initial [kN] (mooring chains)
| Case | Wave | Current | Wind | Notes |
|---|---|---|---|---|
| Operating | 100-yr Hs, Tp | 10-yr | 10-yr | Strength check |
| Extreme | 100-yr Hs, Tp | 100-yr | 100-yr | Combined extreme |
| Fatigue | Scatter diagram | Long-term | N/A | Fatigue damage |
| Survival | 10,000-yr | — | — | Mooring intact check |
| Installation | Workability Hs | — | — | Operability window |