Finite Element Methods for the Structural Analysis of Tension Leg Platforms for Floating Wind Turbines

This paper represents the condensed version of an original Master Thesis written in 2016 [1]. The main aim lays in the structural analysis of Tension Leg Platforms (TLP) as support structures for Floating Wind Turbines (FWT). Special focus is given to a methodology study of different static analysis methods for components of a FWT support structure by Finite Element Method (FEM). The analysis considers Ultimate Limit States (ULS) only. Based on a given open source TLP design [2], the support structure is fragmented in its components. Each component is categorized, based on whether it can be analyzed by parametric equations or by computational methods. For the components, verifiable by parametric equations, the relevant standards are examined. The analysis of the decomposed support structure shows that existing standards can be applied for many of the components. One specific tubular joint of the support structure is selected and analyzed by computational methods. Considering the complexity of Finite Element Analysis (FEA) for FWT, the performed methodology study compares and evaluates various simulation methods on how loads are applied onto the structure. The methodology study results show that for ULS consideration, all load driven simulation methods are generally applicable. In the prospect of fatigue analyses further developments and improvements are considered crucial. This especially includes a better coherence of the stiffness representation between global load simulation model and local structural analysis model.