1.4.5. Body load results

Various load components acting on each body can be plot within the SeaFEM Postprocess. To this aim, the following menu option can be used.

Postprocess > SeaFEM Graphs

Once the graphs window appears, the ‘Body Loads’ option must be selected from the results type combobox. By doing this, a separate tab will appear for each body the user has defined, which will contain the various load components acting on the body at hand. Available load components read as follows:

  • Total: resultant of all external forces acting on the body. Usually, this is the resultant from adding the hydrostatic and hydrodynamic pressure loads, mooring loads, the gravity effect and any external forces defined by the user. In other special cases, such a total load may also contain the forces and moments due to slender (Morison) elements (if defined by the user), and the effect of additional added mass, stiffness and damping matrices in the case these matrices are also provided by the user through the GUI interface of SeaFEM. Finally, if a damping resonance factor is used (see numerical data for details), the corresponding damping load will be also added to the total load.

  • Reactions: these are the body reactions evaluated as \(R = M·a - F_{t}\) where

    • M is the body mass matrix,

    • a is the vector of linear and angular accelerations and Ft is the vector of total forces and moments defined above. Note that in the case the reactions are due to the forces and moments from other bodies transmitted through the body links, the reactions as defined here are the resultant of all body links attached to the body under consideration. Detailed information on body link reactions is provided in a separate file where body loads are reported individually for each body link instead of the resultant provided here. Hydrostatic: these are the hydrostatic pressure loads evaluated using the hydrostatic restoring matrix, if linear hydrostatics is used, or by actual integration of the hydrostatic pressure over the auxiliary body mesh if the non-linear hydrostatics option is selected. Dynamic: this are the dynamic pressure loads obtained by integration over the body surface of the dynamic pressure obtained when solving the waves (diffraction-radiation) problem.