Buoy and vessel statics

Each buoy and vessel is either included in or excluded from the static analysis, according to the value of included in static analysis for each object.

Notes: You can also use buoy degrees of freedom included in static analysis, on the general data form, to include or exclude all buoys with a single setting.
Also, for 6D buoys, you can include only the translational degrees of freedom (X,Y,Z) and exclude the rotational degrees of freedom. This is sometimes useful as an aid to convergence.

If a buoy is excluded from the static analysis, then when the static analysis is performed OrcaFlex will simply place the buoy in the initial position given on the buoy data form. This will not, in general, be the equilibrium position. Vessels, similarly, are placed in their initial position if excluded from statics.

For buoys and vessels are included in the static analysis, the static analysis finds their equilibrium position using an iterative procedure.

This iterative procedure usually converges successfully, but in some cases can experience difficulties. For ease of convergence, you should try to give good estimates of the true equilibrium positions for the buoy and vessel initial positions. You can often obtain these by running static analyses of a simplified model, and then using the resulting positions as the initial positions in the original, more complex model. The use calculated positions command can be used to automate this procedure.

Note: As a visual aid to help you follow a static analysis, the out-of-balance forces on buoys and vessels can be drawn on the 3D view.