In this paper, structural design and analysis of a composite boat hull was performed. A resin transfer molding manufacturing method was adopted for manufacturing the composite boat hull. The RTM process is an advanced composite manufacturing method that allows a much higher quality product than the hand lay-up process, and less manufacturing cost compared to the autoclave method. Therefore, the RTM manufacturing method was adopted. The mechanical properties of the various aramid fibers and polyester resin were investigated. Based on this, structural design of boat hull was performed using aramid fiber or polyester. After structural design, the optimized resin infusion analysis for RTM manufacturing method was performed. Through the resin infusion analysis, it is confirmed that the designed location of resin injection and outlet is acceptable for manufacturing.
Since the focus on the energy crisis and environmental issues due to excessive fossil fuel consumption, wind power has been considered as an important renewable energy source. Recently, several megawatt-class large-scale wind turbine systems have been developed in some countries. Even though the large-scale wind turbine can effectively produce electrical power, the small-scale wind turbine has been continuously developed due to some advantages; for instance, it can be easily built at a low cost without any limitation of location, i.e., even in the city. In case of small-scale wind turbines, the vertical axis wind turbine (VAWT) is used in the city despite having a lower efficiency than the horizontal axis wind turbine. Furthermore, most small-scale wind turbine systems have been designed at the rated wind speed of around 12 m/s. This aim of this work is to design a high-efficiency 500W class composite VAWT blade that is applicable to relatively low-speed regions. With regard to the aerodynamic design of the blade, parametric studies are carried out to decide an optimal aerodynamic configuration. The aerodynamic efficiency and performance of the designed VAWT is confirmed by computational fluid dynamics analysis. The structural design is performed by the load case study, initial sizing using the netting rule and the rule of mixture, structural analysis using finite element method (FEM), fatigue life estimation and structural test. The prototype blade is manufactured by hand lay-up and the matched die molding. The experimental structural test results are compared with the FEM analysis results. Finally, to evaluate the prototype VAWT including designed blades, the performance test is performed using a truck to simulate various ranges of wind speeds and some measuring equipment. According to the performance evaluation result, the estimated performance agrees well with the experimental test results in all operating ranges.
ABSTRACT:In this work, a structural design on 500W class horizontal axis wind turbine blade using natural-fibre composite is performed. The structural design result of flax composite blade is compared with the result of glass composite blade. The structural design of the wind turbine blade is carried out using the simplified methods such as the netting rule and the rule of mixture. The structural safety of the designed blade structure is investigated through the various load cases, stress, deformation and buckling analyses using the commercial FEM. The structural test of the manufactured prototype blade was performed to confirm the structural analysis results including strains, natural frequencies and deformations. According to the comparison results, it was confirmed that the analysis results are well agreed with the experimental results.
Even though the differential drag type machines of the vertical wind turbines are a bit less efficient than the lift type machines such as Darrieus type machines, they have an advantage of low starting torque. The flapping blade type wind turbine is a specific type of the differential drag machines, and it has no need for orientation as well as quite low starting torque. This work is to develop an innovative 5kW class flapping type vertical wind turbine system which will be applicable to a hybrid power generation system driven by the diesel engine and the wind turbine. The parametric study was carried out to decide an optimum aerodynamic configuration of the wind turbine blade. In order to evaluate the designed blade, the subscale wind tunnel test and the performance test were carried out, and their test results were compared with the analysis results.
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