2.5 Intact stability calculation
The mass and centre of gravity of the whole system are input for the intact stability calculation. For this tutorial a very simplified stability calculation is used. The only input value that is required is the moment of area inertia of the waterline area.
Create the following parameters in the Knowledge Browser:
Parameter name | Dimension | Reference |
BM | [m] | Distance between center of buoyancy and metacenter |
GM | [m] | Metacentric height |
KB | [m] | Distance between keel and center of buoyancy |
KG | [m] | Distance between keel and center of gravity |
Moment_of_Inertia | [m^4] | Moment of inertia of the water plane area in m^4, For this tutorial give a rough estimate |
Include the following parameters in Entity “Intact stability calculation“: “Loa”, “Boa”, “BM”, “COGX”, “COGY”, “COGZ”, “Displacement”, “GM”, “KB”, “KG”, “Moment_of_Inertia”, “Rho”, “T_design” and “QEntityData”.
Create the following relations (either Entity or normal relations, see section 2.3.4 above):
- Loa = ENTITY#(xx).Loa ; In which “xx” is the QEntityID of Entity ”Main Dimensions”.
- Boa = ENTITY#(xx).Boa ; In which “xx” is the QEntityID of Entity ”Main Dimensions”.
- GM = KB + BM – KG
- BM = Moment_of_Inertia / (Displacement/Rho)
- KG = COGZ
- KB = 0.7*T_design
- T_design = ENTITY#(xx).T_design ; In which “xx” is the QEntityID of Entity ”Hydrostatics”.
- Displacement = ENTITY#(xx).Mass In which “xx” is the QEntityID of Entity ”Mass calculation”.
- COGX = ENTITY#(xx).COGX ; In which “xx” is the QEntityID of Entity ”Mass calculation”.
- COGY = ENTITY#(xx).COGY ; In which “xx” is the QEntityID of Entity ”Mass calculation”.
- COGZ = ENTITY#(xx).COGZ ; In which “xx” is the QEntityID of Entity ”Mass calculation”.
- Rho = ENTITY#(xx).Rho ; In which “xx” is the QEntityID of Entity ”Hydrostatics”.
- To show computed values during a dialogue write “@SHOW” behind “QEntityData”.
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