Learning Forum

[nhanani4]

hi. Im new ansys user.

I want to ask if can give suggestion where did i do wrong that get the heave  negative?did it correct the heave motion of floating structure is at structure motion> asctual response> global z?

 

1. or did i put the mooring point at structure at the bottom of structure is not correct?
2. 

2. or the data calculation for axial stiffness is problem?

thank for helping me

[Shuangxing Du]

Getting the heave negative may not be a problem. It just indicates that the COG z-position is below water surface in the time domain analysis.

Please check the followings:

(1) the global coordinate system's origin is defined at the mean water level and z-axis points upwards.

(2) from Hydrodynamic Diffraction -> Solution -> Hydrostatic, check if Ceter of Gravity Position is what you expect.

(3) from Hydrodynamic Diffraction -> Solution -> Hydrostatic, check if Actual Volumetric Displacement is nearly the same as Equivalent Volumetric Displacement.

(4) from Hydrodynamic Diffraction -> Solution -> Hydrostatic, check if horizontal position (x,y) of Center of Buoyancy to be nearly the same as that of Center of Gravity position.