NDLI: Real-Time Hybrid Model Testing of a Top Tensioned Riser: A Numerical Case Study on Interface Time-Delays and Truncation Ratio

Content Provider	The American Society of Mechanical Engineers (ASME) Digital Collection
Author	Sauder, Thomas Sørensen, Asgeir J. Larsen, Kjell
Copyright Year	2017
Abstract	This paper investigates the applicability of real-time hybrid model testing (ReaTHM testing) to the study of offshore systems in deep water. The focus is in particular on slender marine structures connecting floating structures to the seabed, and on how they could be truncated so that a model test setup at a reasonable scale could fit existing hydrodynamic laboratory infrastructures. In this context, ReaTHM testing consists in “substructuring” the slender structures in two parts. At the lower part of the water column, the first substructure is numerical, simulated using a nonlinear finite element method. On the upper part of the water column, the other substructure is physically modelled in an ocean basin. Both substructures interact in real-time through a set of sensors and actuators. This paper addresses through a case study the important issue of accuracy of ReaTHM testing, that is how the behavior of the substructured system varies from that of the emulated system. A top-tensioned riser in 1200m water depth is considered, with two truncation locations: 240m and 600m below the free surface. It is assumed that an artefact is introduced by the ReaTHM test setup, namely a time delay induced by e.g. the numerical calculations, or the actuation system. It is first shown how this artefact influences the accuracy of the setup, and then how the truncation ratio influences the tolerance of the ReaTHM test setup to such an artefact.
Sponsorship	Ocean, Offshore and Arctic Engineering Division
File Format	PDF
ISBN	9780791857649
DOI	10.1115/OMAE2017-62498
Volume Number	Volume 2: Prof. Carl Martin Larsen and Dr. Owen Oakley Honoring Symposia on CFD and VIV
Conference Proceedings	ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering
Language	English
Publisher Date	2017-06-25
Publisher Place	Trondheim, Norway
Access Restriction	Subscribed
Subject Keyword	Water Actuators Top-tensioned risers Oceans Marine structures Ocean engineering Delays Sensors Finite element methods Floating structures Seabed Testing
Content Type	Text
Resource Type	Article

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