Test And Analysis Of Full-field3D Deformation For A Wind Turbine Blade

With the large-scale development and utilization of wind energy, the size and number of leaves are growing more and more bigger. People have paid more attention to security issues of wind turbine blades. Wind-power blade is a very important part of wind turbines, so the test of wind-power blades has the extreme importance. Domestic few scholars have studied the wind turbine blades test experiment, mostly contact, discrete, non-dimensional test methods. In order to overcome and reduce the difficulties and shortcomings of traditional wind turbine blades structure existing in the process of testing, this paper use digital image correlation technique to test wind turbine blades full-field three-dimensional deformation.In order to explore the feasibility and effect of digital image correlation techniques to measure the three-dimensional deformation of the whole wind turbine blades, in this paper, the actual size of wind-power blade under static load experiments was conducted for the three dimensional deformation field observation. Test device platform was erected for wind turbine balde dimensional deformation field observation. In the laboratory to simulate the working state of the blade,the blade was cantilever fixed in the lab device. And through the ropes and crown block, realized the blade in the flapwise direction of the load step by step. Random speckles were made on full scale wind blade surface. The curtain was set-up in the background of wind-power blades to eliminate the influence of background for image acquisition. Double CCD technique was adopted to realize the three dimensional deformation observation.The calibration test of displacement and strain was carried out, and the results show that the method of measurement in testing wind-power blades three-dimensional displacement and strain values has good precision.The key issues in the implementation of this technique were discussed in detail as well, such as speckle, light, backdrop, noise floor etc. The main influence factors and difficulties of the test were analyzed, and the corresponding solutions were proposed. In view of the deformation of the wind-power blade under the load in the flapwise direction is given priority to the out-of-plane displacement,this paper give further analysis for the out-of-plane displacement. The out-of-plane displacements at five discrete points were also measured using the traditional vernier caliper. With vernier caliper measurements as the basic value,the relative error of the out-of-plane displacement measured by DIC was calculated and analyzed. A good agreement between the two measurement results was observed. This article also used ANSYS software to model the wind turbine blades, then analysed and compared the experimental data and simulation data. The two measurement results were in good agreement. The results show that the digital image correlation technique is a useful tool for the measurement of full-field three-dimensional deformation of a wind turbine blade.