Method for real-time hybrid model testing of marine constructions

PhD-student: Stefan Vilsen


Professor Asgeir Sørensen (NTNU)
Associate Professor Martin Føre (NTNU)
Professor Arne Fredheim (NTNU/SINTEF Ocean

Duration: Q1 2014 – Q2 2018

Real-Time Hybrid Model (ReaTHM®) testing is a method that combines traditional hydrodynamic model tests with numerical simulations of constructions in real time.

Marine constructions are dynamic systems that are impacted by many different physical phenomena. Complex hydrodynamics linked to wave loads and viscous flow through net structures create design challenges that make it difficult to guarantee construction safety.  It is thus common to carry out hydrodynamic experiments as part of the design validation process for marine constructions.

The development of new types of aquaculture facilities in exposed, deep water, locations means that complex constructions under near-free surface conditions must be coupled with anchoring systems. This raises challenges for those conducting model experiments due to space constraints imposed by current laboratory infrastructures.

One solution to this is to use hybrid model experiments, in which the construction under study is subdivided into physical and numerical parts that are coupled in real time using an interface with a control system, actuators and sensors.

In this project, a generic system has been developed (see figure) in which a non-linear finite element model has been coupled with a hydrodynamic model experiment.

Based on experience from the development of a control system and test configuration, a proposal has been put forward for a general method for the design and implementation of hybrid model experiments for marine constructions.

  • Vilsen S.A., Sauder T., Sørensen A.J., Føre M. (2019), Method for Real-Time Hybrid Model Testing of ocean structures: Case study on horizontal mooring systems. Ocean Engineering.
  • Vilsen S.A., Sauder T., Føre M., Sørensen A.J. (2018), Controller Analysis in Real-Time Hybrid Model Testing of an Offshore Floating System. Proc. of the ASME 37th International Conference on Ocean Offshore and Arctic Engineering (OMAE).
  • Vilsen S.A., Sauder T., Sørensen A.J. (2017a), Real-time hybrid model testing of moored floating structures using nonlinear finite element simulations. Dynamics of Coupled Structures vol. 4, ch. 8.
  • Vilsen S.A., Føre M., Sørensen A.J. (2017b), Numerical Models in Real-Time Hybrid Model Testing of Slender Marine Systems. Proc. of the IEEE Oceans Conference 2017.