Study On Optimization Design Of Composite Nacelle Cover Of Large-scale Wind Turbines Based On OptiStruct

The optimization and analysis of composite nacelle cover of MW-class wind turbine is of great significance to the reduction of the cost of wind power equipment and the stable operation of wind turbine system.Based on GL2010,the GFRP nacelle cover of wind turbine is analyzed and Optimized.The optimization methods of stiffener layout,laying of composite materials and structure are obtained.The design driven by simulation realizes the goal of lightweighting and shorten the design cycle of nacelle cover.It has high engineering application value and theoretical significance.The main research contents,methods and conclusions were summarized as follows:(1)Basic theory of composite mechanics and structure optimization.The structure optimization theory and OptiStruct's application on composite materials are briefly described,preparing for the optimization of GFRP nacelle.Mechanical properties of composite elements,classical laminate theory and single layer strength theory are discussed,which provide theoretical support for the subsequent optimization and evaluation of the optimization.(2)Modeling technology of composite nacelle cover and load calculation under multiple working conditions.Considering the GL2010 and the Structural characteristics of nacelle cover,the FEM model,computationally efficient and suitable for composite optimization,is established.The composite modeling in Hyper Laminate is discussed and a composite material layup method suitable for subsequent size optimization and free sizing optimization is obtained;the wind load calculated with load coefficients of different areas of the nacelle together with the static load,active load and snow load are combined separately ensuring the optimized design feasible.(3)Topography optimization of stiffener.By establishing the concept model of nacelle,setting reasonable optimization interval and design constraints,the optimal scheme of stiffener layout is obtained by topography optimization,which maximizes the rigidity of nacelle with minimum material.(4)Free shape optimization and free sizing optimization.Through the optimization of free shape and free size,the safety guardrail mounting plate and flanging of the nacelle is optimized locally,which improves local state of strain under individual limit conditions and improves the global stability of the nacelle.(5)Size optimization.With detailed DESVAR,the optimal thickness distribution that meets the design requirements of nacelle is obtained through the size optimization under all working conditions,realizing the weight reduction of the nacelle.(6)Evaluation of optimization scheme of nacelle cover.Basic on FEM the optimization scheme is further evaluated by static strength analysis,failure analysis and modal analysis under critical working conditions.The results show that the optimized nacelle meets the strength requirements,resonance and single layer composite failure do not occurs,which proves the effectiveness and feasibility of the optimization design.