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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Aerolastic simulation of wind turbine dynamics

Ahlström, Anders January 2005 (has links)
The work in this thesis deals with the development of an aeroelastic simulation tool for horizontal axis wind turbine applications. Horizontal axis wind turbines can experience significant time varying aerodynamic loads, potentially causing adverse effects on structures, mechanical components, and power production. The needs for computational and experimental procedures for investigating aeroelastic stability and dynamic response have increased as wind turbines become lighter and more flexible. A finite element model for simulation of the dynamic response of horizontal axis wind turbines has been developed. The developed model uses the commercial finite element system MSC.Marc, focused on nonlinear design and analysis, to predict the structural response. The aerodynamic model, used to transform the wind flow field to loads on the blades, is a Blade-Element/Momentum model. The aerodynamic code is developed by The Swedish Defence Research Agency (FOI, previously named FFA) and is a state-of-the-art code incorporating a number of extensions to the Blade-Element/Momentum formulation. The software SOSIS-W, developed by Teknikgruppen AB was used to generate wind time series for modelling different wind conditions. The method is general, and different configurations of the structural model and various type of wind conditions can be simulated. The model is primarily intended for use as a research tool when influences of specific dynamic effects are investigated. Verification results are presented and discussed for an extensively tested Danwin 180 kW stall-controlled wind turbine. Code predictions of mechanical loads, fatigue and spectral properties, obtained at different conditions, have been compared with measurements. A comparison is also made between measured and calculated loads for the Tjæreborg 2 MW wind turbine during emergency braking of the rotor. The simulated results correspond well to measured data. / QC 20100826
2

Development and Implementation of an Advanced Remotely Controlled Vibration Laboratory

Sharafi, Amir January 2015 (has links)
Term of remote-lab is certain types of laboratories which practical experiments are directedfrom a separate area by remote controller devices. This study is part of developing andupgrading advanced vibration remote laboratory. In the new remote lab, users have theability to measure the dynamic characteristics of the test object similar to the current existingremote lab. But in addition to current existing remote lab, they are capable to modifydynamic properties of the test object remotely by attaching vibration test instruments; such asa block of mass, spring-mass or non-linear spring. Doing several accurate experimental testsremotely on the test object are the toughest issues we faced as designers. In creating anddeveloping of this remote-lab, number of different approaches was adopted for producingwell-defined tests. Also, instead of implementing routine devices and techniques for regularvibration laboratories, the new prototypes were designed by finite elements method (FEM)and LABVIEW. For instance, the desirable test object, the attachment mechanism, usefulapplications, and proper software for managing via internet were prepared.

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