Strcutural Analysis Of MW Graded Wind Turbine Mainframe System And Optimization Design

The wind turbine main frame system is one of the most complex load-supporting components in structure and loading aspects.While Engineering calculations can not make exact strength and fatigue analysis for the main frame. So it must be carried out with the help of finite element analysis. The paper focuses on how to delivery characteristics simplify and equivalent treatment on the basis of the structure and load. This provides an analysis of ideas and methods for the main frame analysis system and has certain guiding significance.The main frame system withstand complex alternating dynamic loads , so it is likely to generate resonance and fatigue damage. Based on the static strength analysis , it must carried out the modal analysis and fatigue analysis.The paper focuses on the elaboration of the theory and method of fatigue analysis and also provides a more detailed explanation about fatigue analysis. So it has some theoretical and practical values.In this paper,the main frame has been made optimization analysis. With this analysis we can obtain better optimization of the structure and weight reduction, as well as lower material and transport costs.In this paper,the main research contents as follows:①The main frame strength analysis, in this part, it mainly analyses the structure and loading of the main frame system. According to the structure and loading characteristics of the main frame, the system modeling has been simplified. And the finite element model has also been tested and verified. Finally the strength of the main frame based on finite element analysis results has been evaluated.②The main frame modal analysis,in this part,it briefly introduces the theoretical basis of the modal analysis. It establish the finite element model of the modal analysis and boundary conditions by the actual situation, and then obtain a more accurate mode results. At last it will compare with the driving frequency of the wind wheel to avoid the resonance phenomenon.③The strength analysis of connecting bolts in main frame ,in this part, In order to get more accurate results, it is better to adopt a way of sub-model to build the model. it analyses the strength of the connecting bolt between the main frame and shaft bases as well as between the main frame and the yaw bearing respectively. ④Fatigue analysis of connecting bolts between main frame and sub frame,this part gives an outline of fatigue theory and particularly describes the method of fatigue analysis when using MSC. Marc and MSC. Fatigue software. It also focuses on stating the method of the bolt fatigue analysis.⑤Optimization design of main frame,this part uses the topology optimization technology to optimize the main frame. It achieves the goal of weight loss and quantitative understanding on the main frame structure optimization. The exoploratory study done on optimization of the mainframe.It also establish a compacted foundation for the fixed independent research about main frame.