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6D buoys: Properties report |
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6D buoys: Properties report |
The 6D buoy properties report is available from the popup menu on the data form. It reports the following:
The force due to gravity acting on the buoy's mass.
The weight of water displaced by the buoy's volume, based on a nominal water density.
Weight $-$ buoyancy.
The buoy's mass.
The mass of water displaced by the buoy's volume, based on a nominal water density.
Mass $-$ displaced mass.
The position, in local buoy axes, of the centre of mass.
The volume of the buoy.
Position, in local buoy axes, of the centre of volume.
$\sqrt(\text{mass moment of inertia} / \text{mass})$.
The total contact area data: if a value of ~ is set on the data form, then the value reported here is the default value calculated by OrcaFlex.
The number of vertices in the wire frame drawing. Contact is calculated at each of these vertices.
Total contact area / number of vertices.
These are only reported if the buoy is included in statics.
The static analysis searches for an equilibrium position for the buoy – that is, a position for which the resultant force and moment on the buoy is zero. We refer to the resultant force and moment as the out-of-balance load. Because computers have limited numerical precision the static analysis cannot always find a configuration where the out-of-balance load is exactly zero. OrcaFlex accepts a position as a static equilibrium position if the largest out-of-balance load component is less than the statics accuracy.
The statics force accuracy is $\textit{tol} \times |\vec{f}_\textrm{char}|$ and the statics moment accuracy $\textit{tol} \times |\vec{m}_\textrm{char}|$, where $\textit{tol}$ is the whole system statics tolerance and the characteristic force, $\vec{f}_\textrm{char}$, and characteristic moment, $\vec{m}_\textrm{char}$, are calculated internally based on the forces and moments applied by coupled objects.
Reducing the tolerance value will give a more accurate static equilibrium position, but will take more iterations. OrcaFlex may not be able to achieve the tolerance specified if it is too small, since the computer has finite numerical precision.