الفهرس 
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Abstract
The blade of a horizontal axis wind turbine is considered as the most critical element in wind energy generation. The design and structural analysis of a segmented horizontal axis 7 meter long blade is a research and development project funded by the Science and Technology Development Fund in Egypt. This thesis presents the conceptual design of the segmented blade and manufacturing a 7m long prototype and suggests a framework for testing of the prototype according to IEC-61400-TS-23. This framework includes design, manufacturing and structural analyses of a multi-purpose test rig that facilitate performing all tests on the blade without dismounting it each time, performing the proper tests on the blade and using Pre-testing method in which a numerical model of a blade is used beside scaled-down models to predict the performance of the blade during design stage to improve its efficiency. With this intention, the blade mass is measured and center of gravity is determined using fixed jig and movable jig method. Experimental modal analysis is performed by free vibration method and the natural frequencies are obtained and they found to be far from operational speeds which mean that the blade is safe from resonance. The static bending tests in flapwise and edgewise directions are performed using hydraulic cylinder at the tip of the blade and the load-deflection curve is plotted. Acoustics Emission AE method is used during static bending tests for further details about the blade status in the tests. The tests revealed showed slight superficial defects.
The resonant fatigue test is performed for ten millions loading cycle. An eccentric cam mechanism is used for harmonic excitation. The relations between the changes in natural frequencies in flapwise and edgewise directions and the number of loading cycles are studied. Slight differences occurred in the natural frequencies and they are attributed to environmental effects. Pre-testing of wind turbine blades is important for further improvements to blades during design stage. Scaled-down physical and numerical models are developed and a full-scale blade is made like the conventional ones to generalize the Pre-testing approaches. The first approach is inspecting the numerical solutions accuracy by experimentally analyzing the scaled-down prototype which helps in expecting the accuracy of full-scale numerical solutions. The second approach is using Buckingham π- Theorem to relate between scaled-down model and full-scale model so the results of full-scale model can be predicted.