| The wind power tower drum is the part of the cylinder that supports wind turbine.It has a certain height to supprot the wind turbine runs at a suitable height,and has sufficient strength and rigidity to prevent the wind turbine under severe serious dumping conditions.The wind power tower drum has characteristics of superior structural performance,high safety and beautiful appearance,the manufacturing forming process is cold rolling steel plate by using coiling machine.The research content of this subject is to carry out finite element simulation on the manufacturing process of a 2MW wind power tower drum,analyze the characteristics of the coiling forming and the key factors affecting the forming effect,and according to the research results,the coiling forming process is optimized.Coling forming is a traditional sheet metal bending process,its remarkable feature is its high forming efficiency,it is often used to roll a thick plate into a workpiece with equal curvature or variable curvature.Wind power tower durm contains a straight section and a cone section,the coiling forming process is a complex material processing process involving a variety of nonlinear problems,such as geometric nonlinearity and contact nonlinearity,and a certain rebound after unloading,the calculation of the rebound is the key to the forming effect.At present,the widely used theories are the rebound theory derived from the pure plastic bending theory and the deformation theory considering the secondary rebound of the sheet,but there is still a lack of a general calculation theory that can accurately describe the plastic deformation characteristics of the steel sheet.In terms of production processing,the calculation of the theoretical formula is combined with multiple coiling test to determine the tower durm coiling process.In this paper,the content and method of finite element research on wind turbine tower durm coiling forming are introduced in detail.Firstly,the tower coiling forming process is taken as the research object,and the large-scale nonlinear finite element software MSC.MARC is used to simulate the existing processing process.The geometric parameters and process parameters of the production equipment(symmetrical three-roll coiling machine,model: 11S-150/220×4000mm)were modeled to investigate the key factors affecting the coiling forming of the cylinder.The stress and strain distribution of the sheet during the forming process of the tower drum,the deformation characteristics in the width direction,the length direction and the thickness direction,the neutral layer offset,the equivalent plastic deformation,the rebound change law and the rebound calculation method are mainly studied.And so on.The results show that,in the case of material has been determined,the bending radius of the sheet after rebound is mainly determined by the amount of pressing of the upper roll and the center distance of the lower roll.The thickness bending radius ratio of the sheet have a certain influence on the rebound.The increase of the number of times is beneficial to reduce the residual stress growth rate and the residual stress,but the first pressing amount should be no less than 10 mm,and the rolling speed has little effect on the residual stress and residual strain.Then,based on the analysis of the deformation characteristics of the tower durm forming,the optimization process of the forming process was carried out,and the stress strain and rebound of the sheet with less number of coiling times were studied by calculating of finite element method.The rebound results are compared with the empirical formula,the formula of pure plastic theory and the deformation theory considering the secondary rebound.The results show that the analysis results of the finite element method and the empirical formula are in the pure plastic rebound theory and the deformation theory considering the secondary rebound.The analysis results of the finite element method agree well with the calculation results of the empirical formula,indicating that the calculation result of the finite element method is effective.This subject researches and optimizes the wind power tower drum coiling forming process,and verifies the calculation result of the finite element method.It has certain engineering significance and is beneficial to the research and development of wind power tower drum coiling forming process. |
