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Zhang L.-A.,Shandong University of Technology | Zhang L.-A.,China University of Mining and Technology | Zhang L.-A.,Lianyungang Zhongfu Lianzhong Composite Group Co. | Wang Z.-B.,China University of Mining and Technology | And 2 more authors.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

Aiming at self-synchronous vibration phenomenon in single-point fatigue loading test process of a wind turbine blade, the dynamic model of the single-point fatigue loading system based on Lagrangian equation was established and the influence factors of the self-synchronous vibration phenomenon were obtained. Applying the phase plane method, the vibration system was converted into an autonomous system. Then the vibration system's simulation model was built with Matlab/Simulink and the basic laws of the self-synchronous vibration phenomenon with different initial phases were deduced. At last, a set of single-point fatigue loading test equipments used to test the correctness of the dynamic model and the simulation one was set up. The experimental results showed that under the premise of the load source rotary drive frequency being the same as the blade's natural frequency, the self-synchronous vibration phenomenon occurs when the initial phase difference between them is less than π/20, the amplitude of the blade is the maximum and stable; when the initial phase difference is π/8, the self-synchronous vibration phenomenon is weak, and the amplitude of the blade gradually approaches a smaller value after fluctuating for a period of time; when the initial phase difference is π, the self-synchronous vibration phenomenon does not occur and the amplitude of the blade is unstable. The above conclusions provided a theoretical basis for the control algorithm of further fatigue loading tests. ©, 2015, Chinese Vibration Engineering Society. All right reserved.


Leian Z.,Shandong University of Technology | Leian Z.,China University of Mining and Technology | Leian Z.,Lianyungang Zhongfu Lianzhong Composite Group Co. | Xuemei H.,Shandong University of Technology | Guangming Y.,Shandong University of Technology
Open Mechanical Engineering Journal | Year: 2015

The fatigue life of MW wind turbine blade was assessed by applying theoretical calculation and test verification. Firstly, the fatigue characteristic curve of FRP material was obtained based on Palmgren-Miner damage theory. Furthermore, The fatigue life of Aeroblade1.5-40.3 wind turbine blade using multistage loading accumulative damage theory could be evaluated over 20 years accordingly. Then the coordinate system of wind turbine blade and its Bladed simulation model were set. By calculating fatigue loading, the moment distribution of fatigue test was obtained. Finally, the blade’s fatigue loading system driven by an eccentric mass was built and the multi-level amplitude resonant mode was adopted to carry on the test. Almost three months’ test results showed that the blade vibrating amplitude was constant, which illustrate the little variation of stiffness of loading point. The stable of stiffness could testify the fatigue life of blade was over 20 years. The results of in-site experiment were basically consistent with the theoretical calculation. © Leian et al.; Licensee Bentham Open.


Leian Z.,Shandong University of Technology | Leian Z.,China University of Mining and Technology | Leian Z.,Lianyungang Zhongfu Lianzhong Composite Group Co. | Xuemei H.,Shandong University of Technology | Guangming Y.,Shandong University of Technology
International Journal of Smart Home | Year: 2015

In the process of full-scale static loading test of wind turbine blades, the loading forces all had relatively strong coupling effect, which seriously affected the accuracy of the test result. In order to eliminate this effect, firstly, a vertical static loading device for 10MW wind turbine blades was established and the coupling rule of loading force was obtained. Then, a control algorithm was put forward based on fuzzy theory. This algorithm took the error of loading force, error's change rate as the input variables and the opening degree of proportional valve as the output variable. A control strategy based on this algorithm was constructed. In the end, the static device took the max flapwise of aeroblade5.0-62 wind turbine blade as example to conduct loading test. The result suggested the algorithm in this paper could ensure that the loading forces on five nodes always kept uniform changing and the control errors were respectively less than±2KN, ±2KN,± 2KN,± 2KN and±1KN. When in the 100% phase, the loading force could be finely maintained at the set value. The statistical results showed that the error rates of loading force with control algorithm were smaller than those without control algorithm. The test results verified the feasibility of control strategy applying to full-scale static loading test for wind turbine blades.


Zhang L.,Shandong University of Technology | Zhang L.,China University of Mining and Technology | Zhang L.,Lianyungang Zhongfulianzhong Composite Group Co. | Huang X.,Shandong University of Technology
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2015

A single-point fatigue loading system of wind turbine blade was designed. Vibration mathematical model of wind turbine blade under single-point fatigue loading driven was derived based on Lagrange equation. The parameters influencing vibration characteristics were obtained. The simulation model of the vibration system was built with Matlab/Simulink software, and the vibration characteristics of the blade whose first-order natural frequency is 0.92 Hz were obtained. When the loading frequencies were 0.80 Hz and 0.85 Hz, the loading point amplitudes were both less than 300 mm; when the loading frequency was 0.95 Hz, the loading point amplitude reached a large value of about 400 mm and the blade approximately resonated with the loading source, which could satisfy the requirement of fatigue test; when the loading frequencies continued to increase to 1.00 Hz and 1.20 Hz, the loading point amplitudes reduced to 220 mm and 100 mm. At last, a single-point fatigue loading test was conducted, and the test results were consistent with the simulation results, the validity of vibration mathematical model and simulation model were verified. The above conclusions have important reference value for fatigue loading test of wind turbine blade. ©, 2015, Science Press. All right reserved.


Zhang L.,Shandong University of Technology | Zhang L.,China University of Mining and Technology | Zhang L.,Lianyungang Zhongfu Lianzhong Composite Group Co. | Huang X.,Shandong University of Technology
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2015

In order to eliminate coupling effects of the load in the full-size static test process of wind turbine blades, first of all, a multi-node static loading test system was built. The coupling law between loading forces from test on site was found. Then the dynamic master method was used to confirm the slowest loading node. Taking loading force error and its error rate as input variables and the motor speed as output control variable, a fuzzy coordinated control algorithm was constructed. Finally, min flapwise direction of aeroblade 2.0-48.8 wind turbine blade was tested. The test results show that the coordination control algorithm can guarantee that four node loading forces always maintain uniform change. The loading forces can preferably maintain at a set value, and the control errors of the entire loading process are less than ± 3, ± 3, ± 4, and ± 4 kN, respectively, which can validate the feasibility of the control algorithm being applied to the full-size static loading tests of wind turbine blade. ©, 2015, Science Press. All right reserved.


Zhang L.-A.,Shandong University of Technology | Zhang L.-A.,China University of Mining and Technology | Zhang L.-A.,Lianyungang Zhongfu Lianzhong Composite Group Co. | Huang X.-M.,Shandong University of Technology | Yao J.-K.,Shandong University of Technology
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

Aiming at lack of driving capacity and longer test period of a single-point fatigue loading system, a dual-point fatigue loading system for wind turbine blades was designed. By simplifying the loading system rationally, its electromechanical coupling mathematical model was established, and then its simulation model was built with Matlab/Simulink software. By simulating the electromechanical coupling process of the dual-point fatigue loading system, the basic influence laws of different motor speeds and different initial phases on the electro-mechanical coupling process were obtained. Finally, a small dual-point fatigue loading test system for wind turbine blades was set up. The test results agreed well with the simulation ones. The correctness of the mathematical model and simulation model were validated. The study results provided a theoretical basis for the subsequent precise control of dual-point fatigue loading tests and optimal design of blades. ©, 2015, Chinese Vibration Engineering Society. All right reserved.

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