The team of Aktis Hydraulics have developped Aktis Dynamic Mooring Analysis. The model is a fully validated time-domain mooring analysis (DMA) software. Aktis DMA accounts for the following features:
- The frequency dependent hydrodynamic response properties of the moored vessel (derived
using ANSYS AQWA-LINE) transferred to the time domain using the Convolution Integral
Method (Cummins, 1962) for time varying radiated wave damping.
- First-order and second-order (slowly varying drift) including mean drift wave forces. This
intrinsically includes the wave shielding or other interaction effects by nearby vessels.
- Wave schematisation including various spectral shapes and directional spreading (2D or 3D
wave spectra) and application of multiple wave systems (e.g. wind waves and swell from different
- Hull-flow interaction forces (OCIMF);
- Time varying wind forces, including directional variability for industry standard wind spectra (API;
NPD and other), also accounting for wind shielding by close-by objects; wind coefficient from
- Non-linear mooring lines (enabling wires equipped with tails) and fender forces;
- Viscous damping terms for roll and yaw motions;
- Six degrees of freedom (or Nx6 for N interacting bodies) response by properly accounting for the
radiated wave forces and coupling of e.g. wind induced roll motions transferred into sway
motions by the fendering system.
- Time-domain evaluation of innovative mooring systems such as Cavotech Mooring Master and the KRVE ShoreTension.
DMA output consists of time-series of all basic vessel motions (surge, sway, heave, roll, pitch, yaw), related velocities and accelerations and motions at specific locations (e.g. manifold) if needed. For STS operations also relative motions between the vessels can be output. Other output includes all mooring loads (mooring lines, hooks/bollards, fenders) and elongations/deflections. The output can be statistically and spectrally analysed.