The Research On Repair Technique Of Composite Blade

The wind energy, which is a clean and renewable source, gives a good solution to the world's energy crisis and meets environmental protection requirements of people. Therefore,the wind power technology attracts worldwide attention. Wind turbine blade is the key component of the system. It always arises various defects and injuries in the process of manufacture and use, because of its great shape and much more complex overlay. That not only affects the safety of production, but also causes economic losses.Taking into account the materials used in wind turbine blades, this paper chosed the system of E-glass fiber woven roving/epoxy resin to prepare sheet, and embedded defects in the sheet. The mainly defects were air bubbles, uneven infiltration, dry spots and so on. Then this paper used several different methods (such as hand lay-up process, resin injection, resin filling and perfusion,etc) to repair various defects. After the samples were repaired, it studied the effect of various repair methods by mechanical property test, and summed up the repair methods applicable to different defects. The results showed that:no matter what defects can affect the mechanical properties of products; hand lay-up molding applied to repairing bubble on the surface, but it was ineffective for internal defect repair; resin injection, resin filling and perfusion were much applicable to repair internal damage and uneven infiltration.The force attached to wind tubrine blades in the air is very complex.Therefore, in the process of overlay, wind tubrine blades not only use woven roving, but also unidirectional and triaxial fabric are used to improve its performance. This paper used the system of triaxial E-glass fiber fabric/epoxy resin to prepare sheet, manufacturing defects and repairing by replacing damaged part. The different fiber and resin formula were used to repair the defects with the same overlay. By mechanical properties test, this paper researched the effect of different types of fibers, resin matrix and excavation filling mend, to the repair of defects. The results showed that:as the depth of defect(size:20mm*10mm)increased, the tensile strength decreased significantly, and when the defect's depth exceeded half of the sample's thickness, the tensile strength reduced to less than half the original; there were basically no increase after repair. Regardless of the formula, the effect after repairing was basically consistent when the size and depth of the defects were same. In the stretching process, the samples, which were repaired by excavation filling mend, appeared lamination along the repaired region firstly and then fractured. But the fault zone and the tensile strength of upper and lower levels were inconsistent. The repair by replacing the damaged parts, which were not as effective as expected, had little meaning, so we should try to use other repair methods.