Search

Small H-Darrieus wind turbines have become popular in the wind power market because of their many advantages, which include simplicity of design, low construction costs, and they are thought to represent an adequate solution even in unconventional installation regions. The blade is generally considered as the most important component of the wind turbine system because it controls the efficiency of the turbine. The blade structure must be designed to support the difficult environmental conditions (e.g., wind, and snow) encountered during the operational life of the wind turbine. This current study uses three-dimensional (3D) modeling and structural strength analysis to fabricate two straight blades (aluminum and galvanized steel) for a small H-Darrieus wind turbine. The 3D modeling of the blade structure is performed using SolidWorks, a computer-aided design (CAD) software package, and the structural strength analysis uses the Finite Element Analysis (FEA) technique to identify the stiffness, resistance, and reliability of the blade structure. The simulation results obtained indicate that no structural failures are predicted for either of the two structures tested because the factors of safety are larger than one, and the all maximum deflections are within the allowable deformation limits for the materials. Manufacturing processes for the two structures are described. [ABSTRACT FROM AUTHOR]

The study deals with the numerical analysis aspects that are necessary for identifying of modal parameters of the tower structure as the most important part of the horizontal axis wind turbine, which are basic for the dynamic response analysis. In the present study, the modal behavior of an actual 55-m-high steel tower of 850 KW wind turbine (GAMESA G52/850 model) is investigated by using three-dimensional (3D) Finite Element (FE) method. The model was used to identify natural frequencies, their corresponding mode shapes and mass participation ratios, and the suggestions to avoid resonance for tower structure under the action wind. The results indicate that there is a very good agreement with the fundamental vibration theory of Euler-Bernoulli beam with lamped masse in bending vibration modes. When the rotor of the wind turbine runs at the speed of less than or equal to 25.9 rpm it will not have resonant problems (stiff–stiff tower design). Furthermore, in case the rotor runs at the speed of between 25.9 and 30.8 rpm, the adequate controller is necessary in order to avoid the corresponding resonant susceptible area of the tower structure (soft–stiff tower design). [ABSTRACT FROM AUTHOR]

Sun-tracking system (STS) is a key factor for solar photovoltaic (PV) future and new answers for the solar market. It will expand large-scale PV projects (PV farms) worldwide, and it is possible to collect more energy from the sun. PV farms consist of thousands of STS that are subject to dynamic loads (wind, snow, etc.), vibrations, and gravitational loads. This paper presents the structural dynamic analysis of a 24 m² bi-axial STS (azimuth-elevation) at different elevation angles based on its modal parameters (natural frequencies, modal shapes, and modal damping ratios) and dynamic performance indices (modal participation factors (MPF), forcing frequencies, and mechanical quality factors) by means of the finite element analysis (FEA). The simulation results show that the structural dynamic design of the STS meets the desired structural requirements and agrees well with structural dynamic standards (EN 1991-1-4 and ASHRAE). These results can be used for further analysis on optimal design and vibration safety verification for the bi-axial STS (PV applications). [ABSTRACT FROM AUTHOR]