INTELLIGENT synergy of Fluid Structure Interaction (FSI) and FEM.

Each structure interacts with the surrounding and enclosed media. As a specialized service provider for advanced Finite Element calculations, we consider this fluid structure interaction (FSI) within the common computing environment of ANSYS Mechanical, ANSYS CFX and ANSYS AQWA.

Each vibrating structure transmits structure-borne noise into the surrounding structures and radiates noise into the surrounding medium. We investigate the vibration behavior of your design and evaluate the influence of damping elements and elastic bearings on the propagation of structure-borne noise. We also consider the influence of the surrounding medium on the vibration.

Afterwards we evaluate the sound radiation in the medium. The radiated acoustic power as well as the sound pressure and sound pressure level are determined by the fluid structure interaction (FSI) within the finite element simulation.

Underwater acoustics is an area that is becoming increasingly important. Not only for military projects, but also in civil shipping and the offshore industry, noise protection concepts have a high priority. We support you in computational proof of the effectiveness of these concepts through our powerful numerical calculations and many years of experience. We also recommend the literature published by us on this topic

For floating structures, the individual hydrostatic property is of crucial importance. In ships in sea state as well as uneven load high bending moments arise within the ship structure. This is particularly important for project loads and heavy load transports by sea.

We perform hydrostatic calculations to determine the effect of the cargo on the stability of the vessel. Then we take into account the hydrostatic loads on the ship structure as well as the deformation of the hull due to swell and load in the global strength calculations.

Seakeeping behavior of ships and offshore structures

Every floating structure is stimulated by the prevailing sea state and moves in its degrees of freedom. Already during the concept phase, this behavior as well as the resulting hydrodynamic loads can be predicted by numerical simulations. These calculations are not only cheaper than model tests; they also offer the advantage of being able to cost-effectively consider variation calculations as well as different excitation frequencies and angles.

As we are specialized in numerical calculations, we use the software ANSYS AQWA to simulate the seakeeping behavior.

Hydrodynamic loads on ship structures

Especially with specialized ships as well as catamarans and Small Waterplane Area Twin Hulls (SWATHs), the load resulting from the sea state is crucial for the global strength. Thus, diagonally applied swell can exert torsional loads on the vessels and their connections.

We determine the resulting hydrodynamic and hydrostatic pressures as well as accelerations acting on the ship’s structure through the hydrodynamic calculations with ANSYS AQWA. These loads are used to perform a global strength calculation using the Finite Element method. In this way, an effective and reliable statement about the strength of the ship structure can already be made in the concept phase.

Especially for ships that carry project cargo and heavy loads, the accelerations resulting from the sea state are of crucial importance. Due to the typically high center of gravity of the load as well as the high weight, considerable moments arise which act on the ship structure as well as on the load.

We determine the acting accelerations according to current standards or by a calculation with ANSYS AQWA. Through a detailed FEM model we determine the stresses within the project cargo, the substructure as well as the ship structure.

First, the cargo to be secured is modeled. If necessary, the surrounding ship structure, existing hatch covers and substructures are modeled. The braces, whether chains or lashing straps, are modeled as one-dimensional elements that can only transmit tensile forces. The preload of this cargo securing is also taken into account.

This procedure can be used to demonstrate the structural integrity of the cargo as well as of the ship, barge or platform. It is also recorded whether the preloads are sufficient or the breaking loads of the cargo securing are achieved.

Quality is the opposite of fortune.


CFD simulation with FSI and FEM
Seakeeping and ocean loading
Underwater acoustic and sound radiation


A selection of our references:

  • Reduction of the roll motion of the landing stage Falckenstein by a vibration damper
  • Underwater noise preopagation during offshore pile ramming (HELWIN Alpha, BARD OFT1, BARD OFT2)
  • Strength analysis, modal analysis, certification assistance and Investigation of the underwater noise radiation and propagation for a small bubble curtain (SBC)
  • Strength analysis, modal analysis, CFD calculation, technical drawings and design brief for an offshore wind energy converter as a guyed foundation
  • Numerical representation of model tests within a wave channel of the roll movement by coupled floating objects
  • Numerical simulation of the seakeeping behavior of an MPSSU and comparison to model tests and investigation of the structural strength due to the hydrodynamic ocean loads (read more about this simulation here)



S.M.I.L.E. - FEM


Winkel 2
D-24226 Kiel / Heikendorf
fon: +49 431 - 210 80 20
fax: +49 431 - 210 80 28