The Experts below are selected from a list of 59376 Experts worldwide ranked by ideXlab platform
Jason Jonkman - One of the best experts on this subject based on the ideXlab platform.
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inverse load calculation procedure for offshore wind turbines and application to a 5 mw wind turbine Support Structure
Wind Energy, 2017Co-Authors: T Pahn, Raimund Rolfes, Jason JonkmanAbstract:A significant number of wind turbines installed today have reached their designed service life of 20 years, and the number will rise continuously. Most of these turbines promise a more economical performance if they operate for more than 20 years. To assess a continued operation, we have to analyze the load-bearing capacity of the Support Structure with respect to site-specific conditions. Such an analysis requires the comparison of the loads used for the design of the Support Structure with the actual loads experienced. This publication presents the application of a so-called inverse load calculation to a 5-MW wind turbine Support Structure. The inverse load calculation determines external loads derived from a mechanical description of the Support Structure and from measured structural responses. Using numerical simulations with the software fast, we investigated the influence of wind-turbine-specific effects such as the wind turbine control or the dynamic interaction between the loads and the Support Structure to the presented inverse load calculation procedure. fast is used to study the inverse calculation of simultaneously acting wind and wave loads, which has not been carried out until now. Furthermore, the application of the inverse load calculation procedure to a real 5-MW wind turbine Support Structure is demonstrated. In terms of this practical application, setting up the mechanical system for the Support Structure using measurement data is discussed. The paper presents results for defined load cases and assesses the accuracy of the inversely derived dynamic loads for both the simulations and the practical application. Copyright © 2017 John Wiley & Sons, Ltd.
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offshore code comparison collaboration continuation oc4 phase i results of coupled simulations of an offshore wind turbine with jacket Support Structure
Journal of Ocean and Wind Energy, 2012Co-Authors: Wojciech Popko, Jason Jonkman, Fabian Vorpahl, Adam Zuga, M Kohlmeier, Amy Robertson, Torben J Larsen, Kristian Saetertro, Knut M Okstad, James NicholsAbstract:In this paper, the exemplary results of the IEA Wind Task 30 “Offshore Code Comparison Collaboration Continuation” (OC4) Project – Phase I, focused on the coupled simulation of an offshore wind turbine (OWT) with a jacket Support Structure, are presented. The focus of this task has been the verification of OWT modeling codes through code-to-code comparisons. The discrepancies between the results are shown and the sources of the differences are discussed. The importance of the local dynamics of the Structure is depicted in the simulation results. Furthermore, attention is given to aspects such as the buoyancy calculation and methods of accounting for additional masses (such as hydrodynamic added mass). Finally, recommendations concerning the modeling of the jacket are given.
Y.c. Saxena - One of the best experts on this subject based on the ideXlab platform.
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Non-linear structural analysis of cold mass Support Structure of the Steady state Superconducting Tokamak SST-1
21st IEEE NPS Symposium on Fusion Engineering SOFE 05, 2005Co-Authors: Bharat Doshi, K.j. Thomas, C. Ramdas, Y.c. SaxenaAbstract:The SST-1 is a steady state super conducting tokamak, which is in the final phase of commissioning tests. It has a major radius of 1.1 m with plasma minor radius of 0.2 m, with maximum toroidal magnetic field of 3 Tesla at the plasma center. The mission of the SST-1 project is to address physics and engineering issues related to steady state tokamak operation. The superconducting magnet system of SST-1 comprises of Toroidal field (TF) and Poloidal field (PF) coils. The 16 TF coils are nosed and clamped towards the in-board side and are Supported toroidally with inter-coil Structure at the out-board side, forming a rigid body system. The 9 PF coils are clamped on the TF coils Structure. The integrated system of TF coils & PF coils forms the cold mass of @ 50 Ton weight. This cold mass is accommodated inside the cryostat and freely Supported on the 16 cantilevers welded to the toroidal rigid Support ring at 16 locations and Support ring in-turn Supported on 8 columns of machine Support Structure. During the operation this cold mass attains a cryogenic temperature of 4.2K in the hostile environment of high vacuum 1times10-5 mbar. The thermal excursion of cold mass and its Supporting Structure during this cool down results into severe frictional forces at the Supporting surfaces. In this paper, we discuss the effect of coefficient of friction (mu) on von-Mises stresses in cold mass Support Structure of SST-1 machine and need for lubrication, by performing non-linear (contact) structural analysis, using Finite Element Analysis code ANSYS. We estimate the maximum stresses in the Structure for various coefficients of friction and compare them with analytical values. Analysis results shows that there is a design requirement of introducing a thin layer of solid lubricant film of MoS2 having co-efficient of friction 0.05 between the sliding surfaces to control the stress contribution due to the friction
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Support Structure of toroidal field magnet system of SST-1
17th IEEE NPSS Symposium Fusion Engineering (Cat. No.97CH36131), 1997Co-Authors: V.m. Bedakihale, V. Jain, K.n.v. Suresh Babu, K.j. Thomas, B.r. Doshi, Y.c. SaxenaAbstract:The Support Structure of the TF magnet system of SST-1 is described. TF magnet Structure comprises of the casing in which winding is encased and the bottom Support on which full TF magnet assembly is Supported. The design philosophy and the results of analytical and finite element analysis of TF coil casing are presented.
Wieslaw Ostachowicz - One of the best experts on this subject based on the ideXlab platform.
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an application of structural health monitoring system based on fbg sensors to offshore wind turbine Support Structure model
Marine Structures, 2017Co-Authors: Magdalena Mieloszyk, Wieslaw OstachowiczAbstract:Abstract The paper presents an application of Structural Health Monitoring system based on Fibre Bragg Grating sensors dedicated to an offshore wind turbine Support Structure (tripod) model. The experimental investigation was performed in a water basin for the wind turbine model fixed to a turntable that allowed to change the angle between the tripod legs and a wave generator direction. During measurements the Structure was excited by artificial waves and rotor blades rotating simulating effect of wind blowing with different strength. The excitation simulated environmental loading typical for offshore wind turbine. One of the tripod's upper braces contained a flange simulating artificial circumferential crack occurrence. For the Structure under simulating environmental condition four damage indexes (relative and absolute) were developed that allowed to detect the damage and localise it with accuracy to the tripod's leg.
T Pahn - One of the best experts on this subject based on the ideXlab platform.
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inverse load calculation procedure for offshore wind turbines and application to a 5 mw wind turbine Support Structure
Wind Energy, 2017Co-Authors: T Pahn, Raimund Rolfes, Jason JonkmanAbstract:A significant number of wind turbines installed today have reached their designed service life of 20 years, and the number will rise continuously. Most of these turbines promise a more economical performance if they operate for more than 20 years. To assess a continued operation, we have to analyze the load-bearing capacity of the Support Structure with respect to site-specific conditions. Such an analysis requires the comparison of the loads used for the design of the Support Structure with the actual loads experienced. This publication presents the application of a so-called inverse load calculation to a 5-MW wind turbine Support Structure. The inverse load calculation determines external loads derived from a mechanical description of the Support Structure and from measured structural responses. Using numerical simulations with the software fast, we investigated the influence of wind-turbine-specific effects such as the wind turbine control or the dynamic interaction between the loads and the Support Structure to the presented inverse load calculation procedure. fast is used to study the inverse calculation of simultaneously acting wind and wave loads, which has not been carried out until now. Furthermore, the application of the inverse load calculation procedure to a real 5-MW wind turbine Support Structure is demonstrated. In terms of this practical application, setting up the mechanical system for the Support Structure using measurement data is discussed. The paper presents results for defined load cases and assesses the accuracy of the inversely derived dynamic loads for both the simulations and the practical application. Copyright © 2017 John Wiley & Sons, Ltd.
Mattias Schevenels - One of the best experts on this subject based on the ideXlab platform.
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Topology optimization of Support Structure layout in metal-based additive manufacturing accounting for thermal deformations
Structural and Multidisciplinary Optimization, 2020Co-Authors: Jeroen Pellens, Geert Lombaert, Manuel Michiels, Tom Craeghs, Mattias SchevenelsAbstract:This paper focusses on topology optimization of Support Structures for metal-based additive manufacturing. Processes based on powder bed fusion are subjected to deformations during manufacturing due to large thermal stresses. Controlling these deformations by adding temporary Support Structures is essential in guaranteeing qualitative end products and improving print success rates. This paper first describes an adapted stiffness tensor formulation for lattice type Support Structures based on a surrogate model. Next, a general inherent strain method is presented to simulate the complex thermal behaviour of the printed part. These ingredients are used in a topology optimization framework that is capable of automatically generating an optimized Support Structure layout to limit the vertical displacements of each layer of the printed part to a specified maximum value. The proposed framework is applied to a 2D and 3D benchmark problem to demonstrate that the vertical deformations induced during the manufacturing process are successfully reduced.
