Frank Dahlhaus

Scale Tests of the GICON®-TLP for Wind Turbines

The paper will present the preliminary design of the so called GICON® - Tension Leg Platform (TLP) as an innovative foundation concept for floating offshore wind turbines.Preliminary results from model basin tests are also shared. This includes the currently ongoing research of comparing calculated and experimental data obtained through extensive wind and wave tank experiments with a scale model of an offshore wind turbine at the Maritime Research Institute Netherlands (MARIN) in June 2013. These tests have provided insights regarding the dynamic characteristics of the GICON®-TLP by analyzing the system’s response to different load cases.The experiments included wind and wave loads, which represent three different sea states, each with three different directions of inflow. The chosen load cases correspond to the proposed location in the German Baltic Sea where the full scale prototype will be erected.Copyright

Comparison of Three Different TLPs for Wind Turbines by Tank Tests and Calculated Results

This paper will give a short overview of the path of development of the so called GICON® - Tension Leg Platform (TLP) for offshore wind turbines. The main part of the paper will provide a summary as well as insights from three different model basin tests. Furthermore, the comparison of a truss like structure (first concept) with a shell type structure (third concept) deduced from the measured results and also by comparison of the natural frequencies will be presented. Both structures were tested in wave tanks in a scale of 1:25. The results also include a focus on the overall dynamic behavior of the structure. In addition to the two 1:25 models, a 1:37 model was also tested at MARIN, utilizing the MARIN stock wind turbine. This model is also included in the comparison. Therefore the different scales are considered but the comparison is presented exclusively for wave loads as only the 1:37 model was tested under wind and wave conditions.Copyright

Design and automation of a pile test facility for offshore foundations and first experimental results

Offshore wind turbines (OWT) in deep-water sites of 50 meters and more require floating substructures. This paper will present a test facility for piles to be used for anchoring floating offshore substructures, in particular a Tension Leg Platform (TLP) substructure. Especially the measurement equipment, the loading cell, the controller technology and the automation will be highlighted. Another focus will be on the scaling laws for the pile and the soil. The paper will also provide an insight into the first experimental studies and their results. Beginning with the bracing types of the ropes between the piles and the OWT TLP substructure, there are two experimental set-ups. Firstly, piles loaded along longitudinal axis and secondly piles loaded with inclined forces transverse to the longitudinal axis. These scenarios are based on the specific loading from the buoyancy force, wave and wind loading. In this model test, the focus is on quasi-static pull-out tests with pulsating stress and cyclic tests with harmonic excitation. Figure 1. Experimental set-ups and loading regimes. F z