Koçlar, Yaşar Çağatay
Planetary gear sets are utilized in various critical applications. Being one of these applications, investigation of wind turbine systems is essential to improve sub-systems such as planetary gearbox, yaw gear, and pitch system under different conditions. In this study, a new finite element model is proposed for obtaining the transient load on the gears of a planetary gearset, and examining the failure types. As an improvement, determination of critical loading scenario for gearset, modeling the blades as a link between the gearset and wind load, and differences between two different beam models are investigated. The model is simulated under reverse load condition which is caused by the sudden change of direction of the wind. The outcome of the simulations shows that the beam model, which takes into account shear deformation, performs within the expected levels according to the literature. Besides, by comparing the outputs of the simulation results, the failure of the gears under an extreme condition is estimated to be due to bending moment on the gear root rather than pitting on the gear tooth surface. As a recommendation for further research, it is suggested to consider reverse load condition in gear designs for wind turbines in order to better understand their behaviour.


Design and implementation of wideband stripline circulators
Dayanıklı, Gökçen Yılmaz; Demir, Şimşek; Department of Electrical and Electronics Engineering (2012)
Ferrite circulators are crucial elements for T/R modules of RADAR systems. Unlike many other mature devices, ferrite circulators have not been replaced by IC devices and have been used in T/R modules since 60s because of two main reasons. Firstly, they do not require environmental elements like capacitors or inductors unlike IC devices. Secondly, their performance is superior in terms of insertion loss, matching and isolation. Basically, they are used for the aim of the discrimination of the incoming and ou...
Genetic algorithm based aerodynamic shape optimization of wind turbine rotor blades using a 2-d panel method with a boundary layer solver
Polat, Özge; Tuncer, İsmail Hakkı; Sezer Uzol, Nilay; Department of Aerospace Engineering (2011)
This thesis presents an aerodynamic shape optimization methodology for rotor blades of horizontal axis wind turbines. Genetic Algorithm and Blade Element Momentum Theory are implemented in order to find maximum power production at a specific wind speed, rotor speed and rotor diameter. The potential flow solver, XFOIL, provides viscous aerodynamic data of the airfoils. Optimization variables are selected as the sectional chord length, the sectional twist and the blade profiles at root, mid and tip regions of...
Dynamic modelling and simulation of a wind turbine
Altuğ, Ayşe Hazal; Yavrucuk, İlkay; Department of Aerospace Engineering (2015)
In this thesis, a dynamic model for a horizontal axis wind turbine is developed for an upwind configuration using the MATLAB/Simulink environment. Blade Element Momentum Theory is used to model the rotor. It is assumed that the rotor blades are rigid and wind speed is uniform. Aerodynamic and gravitational forces are calculated as distributed loads. Verification of the model is done by using the LMS Samtech, Samcef for Wind Turbines software. Aerodynamic properties of the blades, sectional loads and moments...
Modeling and synthesis of circular-sectoral arrays of log-periodic antennas using multilevel fast multipole algorithm and genetic algorithms
Ergül, Özgür Salih (American Geophysical Union (AGU), 2007-06-19)
Circular-sectoral arrays of log-periodic (LP) antennas are presented for frequency-independent operation and beam-steering capability. Specifically, nonplanar trapezoidal tooth LP antennas are considered in a circular array configuration, where closely spaced antennas occupy a sector of the circle. Electromagnetic interactions of the array elements, each of which is a complicated LP antenna structure, are rigorously computed with the multilevel fast multipole algorithm (MLFMA). Genetic algorithms (GAs) are ...
Frequency-resolved spectroscopy of XB1323-619 using XMM-Newton data: detection of a reflection region in the disc
Balman, Şölen (Oxford University Press (OUP), 2010-09-21)
We present the frequency-resolved energy spectra (FRS) of the low-mass X-ray binary dipper XB1323-619 during persistent emission in four different frequency bands using an archival XMM-Newton observation. FRS method helps to probe the inner zones of an accretion disc. XB1323-619 is an Atoll source and a type-I burster. We find that the FRS is well described by a single blackbody component with kT in a range 1.0-1.4 keV responsible for the source variability in the frequency ranges of 0.002-0.04 and 0.07-0.3...
Citation Formats
Y. Ç. Koçlar, “FINITE ELEMENT ANALYSIS OF PLANETARY GEAR SET FOR WIND TURBINES,” M.S. - Master of Science, Middle East Technical University, 2023.