Structural Design And Topology Optimization Of Main Frame Of Offshore Wind Turbine

The main frame is one of the most important basic load-bearing components of a wind turbine,whose structural design optimization is particularly important.The traditional main frame design method mainly relies on the experience of the structural designer to make the initial configuration of the frame.They analyze the strength of the structure based on the analytical method and the finite element method.Then they can modify the frame model based on the results to meet the strength requirements.Traditional methods will lead to problems such as excessive safety margins and longer production cycles.The loading of offshore wind turbines is more complicated than that of onshore wind turbines.It is necessary to consider relevant environmental parameters and load safety factors in load calculations.Therefore,the structural design and topology optimization of the main frame of the offshore wind turbine is to reduce the manufacturing period,improve the durability,and cut the cost of the offshore wind turbine while ensuring the superiority and safety of the main frame structure design.This plays a vital role in the development of offshore wind turbines.The main conclusions of this paper can provide a reference basis for the subsequent development of related structures of offshore wind turbines for enterprises,and have theoretical and practical significance and value.According to Guideline for the Certification of Wind Turbines of the German Lloyd’s Register of Shipping,this article takes a MW-class offshore wind turbine system design project of a company as the research object.According to the working conditions,assembly relations and boundary conditions,the topology optimization,geometric reconstruction and geometric reconstruction of the main frame of the wind turbine are carried out.The finite element strength check is used to achieve the goal of optimizing the structure and reducing the cost.Considering to the three aspects of working conditions,assembly relations and boundary conditions,topology optimization,geometric reconstruction and finite element strength check of the main frame of the wind turbine are carried out to achieve the goal of optimizing the structure and reducing the cost.The main frame of the wind turbine requires topology optimization,geometric reconstruction and finite element strength inspection to achieve the purpose of optimizing the structure and reducing costs,combining the three factors of working conditions,assembly relations and boundary conditions.The main points are divided into:(1)Collect data and establish the topological geometry model of the main frame.Ensure that the assembly position and force transmission path between the parts are consistent with the actual situation.(2)Establish the topological finite element model of the main frame.Assign material properties,mesh division,boundary condition setting,and load loading of extreme working conditions to the main frame topology geometry model.(3)Establish a topology optimization model for the main frame.Based on the variable density method,by establishing the assumed functional relationship between density and elastic modulus,the design area and non-design area of the main frame topology optimization are determined,and the topology optimization problem of the main frame structure is converted into the optimal distribution problem of materials.(4)Establish a geometric reconstruction model of the main frame.With reference to the original main frame model,the topology results are analyzed and compared,and the preliminary optimized design plan is obtained through geometric reconstruction.(5)Finite element strength check.Using extreme conditions to check the strength of the reconstructed geometric model,empirically verify and improve the areas that do not meet the strength conditions or are unreasonable,eliminate structural danger areas,and finally determine the mainframe topology optimization model that meets the requirements.