| Tidal current energy is abundant, clean and renewable. Development and utilization of the tidal energe can alleciate energe crisis effectively, which gains widespread concern in recent years. The horizontal axis tidal current energy turbines owns the highest energy capture capability which makes it become mainstream models in research. Bolt joint of blade root is the key component of the horizontal axis tidal current energy turbines, which carry bending moment and axial load in complex state background in the sea, but hypothesis of traditional theory of bolt joints is inconsistent with the fact of bolt joint of blade root. This paper conducts in-depth investigation on characteristics of bolt joint of blade root.Comparison and analysis have been made among conventional theory of bolt joints, DL/T5154-2003 Aerial Transmission Line Road Post Tower Structure Design and Code for Design of Steel Structure (GB50017). Then the FEM-simulation of blade root bolt joint is carried for researching the characteristics.Theoretical model of tension stiffness and compression stiffness is put forward on the basis of hypothesis of elastic beam and theory of elasticity. Parameters such as preload impacting on the joint stiffness are discussed.On the basis of that a circle of springs which stiffness of compression and tension are different are equivalent of junction of blade and flange, mathematical model of neutral axis is put forward in bending and resultant of bending and axial load, and then the effect of ratio of tension and compression stiffness is investigated.The unloading rate of mouth structure of bladed bolt group joints has been analysed by FEM under axial load and bending. Analytical Formula has been put forward based on above result of FEM and hypothesis of combined thick wall tube. Then the effect of factors such as the friction coefficient has been investigated. |
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