Print Email Facebook Twitter Parametric reduced order modeling of structural models by manifold interpolation techniques Title Parametric reduced order modeling of structural models by manifold interpolation techniques: Application on a jacket foundation of an offshore wind turbine Author Speet, Jeroen (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Precision and Microsystems Engineering) Contributor Langelaar, Matthijs (mentor) Degree granting institution Delft University of Technology Programme Mechanical Engineering | Precision and Microsystems Engineering Date 2017-11-10 Abstract An important aspect of structural design is to obtain adequate knowledge and prediction of the structure’s dynamic behavior. Wind Turbine Manufacturers (WTMs) design their wind turbines for a lifetime of typically 25 years during which the structure has to withstand a large variety of loads, induced by wind- and wave conditions. To obtain a suitable design, numerous load calculations have to be performed for each design. A versatile approach is to use Reduced Order Models (ROMs) to restrict the computational effort that comes withthese numerical techniques, which are also used in other industries (automotive, aerospace, etc. ). However, during the design process, structural changes are often applied. Since ROMs lack robustness with respect to these variations, this approach calls for a reconstruction of the ROM each time the initial model is changed, and the intensive calculation procedure has to be repeated afterwards.With the motivation to improve the limitations of ROMs and how they are used in engineering practice, a literature survey was performed on relevant Parametric Reduced Order Model (PROM) methodologies. Based on appropriate criteria in the context of a WTM’s design cycle, a methodology was selected that interpolates between the precalculated ROMs and their corresponding Reduced Order Basis (ROB). To preserve the properties these matrices typically have (i.e. symmetric-positive definiteness, orthogonality, etc.), the interpolation isperformed on a matrix tangent manifold. For the three most commonly used reduction techniques, being Modal Truncation (MT), Guyan Reduction (GR) and Craig-Bampton (CB), the method is applied on an offshore jacket foundation, designed to support a 5 MW wind turbine, and subjected to realistic designchanges in a local section of the structure. In the presented configuration, the interpolation approach is suitable to update the GR basis with high accuracy. The technique also shows good performance while updating the MT and CB basis, but challenges are found when the structure preserves symmetry properties because of close and multiple eigenvalues of the modes. Furthermore, promising results were shown while updating the ROM matrices, but influence of off-diagonal elements has been observed. Subject ROMPROMreductionreducedparametricFEMstructuraldynamicseigenmode To reference this document use: http://resolver.tudelft.nl/uuid:d1b77685-5b95-4991-bd41-7ce4cdd01605 Part of collection Student theses Document type master thesis Rights © 2017 Jeroen Speet Files PDF ThesisFinalSpeet.pdf 3.71 MB Close viewer /islandora/object/uuid:d1b77685-5b95-4991-bd41-7ce4cdd01605/datastream/OBJ/view