Bionics Design And Mechanical Properties Analysis Of Large-Scale Wind Turbine Tower

As the key load-bearing components of wind turbine, the tower plays an important role in steady operation of wind turbine. The wind turbine increasin gly tends to be large-scale and taller, which put forward higher request to the mechanical property of the tower. Plant multi-body system under the concept of bionics can provide reference for the structural design of the tower. Based on the comprehensive understanding of the current studies on tower, this paper chose the existing problems and future development as the guidance and the theory of bionic design is introduced. Imitation bamboo tower structure is proposed on the basis of systematic study of bionic design methods. By using the finite element method, the static and dynamic characteristics and stability of the tower are analyzed. The specific research content and main conclusions are as follows :1) Proposed application method of bionic structure design theory in the bionic structure design of the tower. The model of the bionic tower based on the bamboo-shaped structure is established. Based on the study and summarize of similarity theory and technology of system comprehensive, the specific method a nd general design process of bionic structure design are put forward and apply to the structure design of tower. Bamboo is been chosen as the biological prototype and verified by calculating the similarity between bamboo and tower from the following three aspects: structure, function, load and constraint. The geometric model of bionics tower which is designed with five stiffening rings which are extracted from the segment feature structure of bamboo is established.2) The finite element model of the pr ototype tower and bionic tower are estanlished. Through the static and dynamic response charateristics of the prototype tower and bionic tower, the improvement of static and dynamic performance of the bionic tower is verified. The ANSYS analysis results show that compared with the prototype tower, the top displacement of the bionic tower could be reduced by 4.75%, thus indicating that the stiffness of bionic tower is improved. The stress distribution of the bionic tower is more gentle compared with the prototy pe tower. The maximum stress of the bionic tower is distributed in the stiffening rings, thus indicating the stress distribution of the bionic tower is improved. The natural frequency of both the prototype tower and bionic tower are all in a reasonable ran ge and the resonance of the wind turbine will not happen. Meanwhile the natural frequency of the bionic tower is higher than the prototype tower and higher-order incremental is greater than lower-order incremental. The vibration characteristic of bionic to wer is improved.3) Put forward the analysis method of linear and nonlinear buckling of the tower. The buckling stability of prototype tower and bionic tower are analyzed from two aspects of linear and nonlinear. The results show that the buckling critical load of bionic tower are all greater than prototype tower in the two analysis patterns. The stability of bionic tower is enhanced. The critical load of first-order linear buckling analysis is greater than the critical load of nonlinear buckling analysis. Therefore, the results of nonlinear buckling analysis are more accurate and conform to the practical results.In conclusion, bionic design of tower by using bionic structure design theory is scientific and the results are proved to be reasonable, provide a theoretical reference for the structure design of the tower. Besides, there are several issues that need to be further explored. One problem is the design standard docking problem between the biological prototype and the design objectives. Another is the structural optimization problem of the bionic tower.