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Load and dynamic characteristic analysis of wind turbine flexible blades
Juchuan Dai,Wei Hu,Xiangbin Shen 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4
Aiming at the Megawatt (MW) scale wind turbine, a dynamic analysis and simulation method is presented to research blade loads and dynamic characteristics. To consider blade flexible deformation, the whole blade was divided into a number of units. Each unit was treated as a rigid body, the flexible connection between two adjacent units is considered. A nacelle coordinate system, a rotating shaft coordinate system, and a blade coordinate system were employed to describe the wind turbine blade. In those coordinate systems, blade inertial load calculation model, centrifugal force load calculation model and gravity load calculation model are established. Combining load model with the whole model of wind turbines, the real-time dynamic simulation model of blade loads was established in Simulink circumstance and a numerical simulation was performed. Based on the simulation analysis, some research results were obtained. When the large instantaneous fluctuation of electromagnetic torque of generator happens, rotor speed does not appear to have large fluctuation due to the inertia of the wind rotor, but the blade vibration speed changes obviously. Gravity has a periodic variation in the process of blade rotation and has a large influence on the edgewise moment. The research results provide a helpful reference for the structure design, operation, and control of wind turbines.
Crashworthiness design of bionic-shell thin-walled tube under axial impact
Lingyun Qin,Shuyi Yang,Hongzhou Li,Juchuan Dai,Guosheng Wang,Qihui Ling,Zhewu Chen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7
Bionic structures have been widely utilized in the crashworthiness design of thin-walled structures due to their superior energy absorption capabilities. This study constructed a bionic-shell thin-walled tube (BST) with excellent crashworthiness based on the structural bionic principle using the shell shape cross-section as the prototype. First, the theoretical model of the mean crushing force (MCF) for BST under axial compression was developed. An experiment was conducted and the reliability of the finite element model was verified. Then, the effects of structural parameters, such as the number of ribs, wall thickness, and inner tube diameter on the crashworthiness of the BST were investigated using the finite element method. Finally, to obtain the ideal configuration of structural parameters, the BST was optimized using the response surface method (RSM) with specific energy absorption (SEA) and crushing force efficiency (CFE) as the optimization objectives and peak crushing force (PCF) as the constraint condition. The results showed that the BST with six ribs exhibited the best crashworthiness under the same mass. The optimized BST-6 was found to have better energy absorption performance than the double circular tube (DCT) and the bionic-horsetail thin-walled tube (BHT). Compared with the DCT, the SEA and CFE increased by 35.15 % and 32.23 %, respectively.