Research On Bearing Capacity Of Pressure Loads Of Cylindrical Shell With Large Diameter-thickness Ratio Under Constraints

Due to the high center of gravity of the wind machine, rely on the hoop pressure produced friction to achieve to enhance the wind turbine overall installation method has good stability, safety and no need to transform the wind turbine tower and other advantages, and has a wide application prospect. However, this method involves the question of the bearing capacity of the wind tower with Large Diameter-thick Ratio. n view of this, the research on bearing capacity of lateral pressure loads of cylindrical shell with large diameter-thick ratio under constraints has theoretical significance and practical application value.In this paper, a certain 6MW wind turbine is taken as the research object. Using’the method of combing finite element method and experiments, bearing capacity of lateral pressure loads of cylindrical shell with large diameter-thick ratio under constraints is studied. First of all, the mechanics model of large diameter-thick ratio cylindrical shell under constraints is simplified, and the relationship between the reaction load of constraints caused by cylindrical shell deformation coordination and the active load is derived. Second, the finite element model with constraints and loads at intervals of 1 is built and the nonlinear analysis is made on ANSYS. On the condition of limit buckling, the maximum lateral pressure load value of the cylindrical shell, under the critical pressure and the structure allowable stress, and the influence law of different intervals between constraints and loads, the clearance coefficient between the constraints and cylindrical shell and other factors on limit buckling of cylindrical shell and strength of materials is obtained. Finally, according to the analysis results, scale model experiment is designed and buckling modes of cylindrical shells under constraints is obtained.The research results show that, under the condition of this study, the ability of restricted cylindrical shell to resist buckling is 16.4 times that of the free buckling, but cylindrical shell appears a certain plastic deformation; Within the scope of the elastic deformation, its bearing capacity increased by 3.5 times. Under the condition of cylindrical shell deformation limited by artificial constraints, constraints and load different relative positions have some influence on the buckling of cylindrical shells, but little impact on the inner tube wall stress; and the clearance has a certain influence on the buckling and strength of cylindrical shell. Finite element analysis and experiment conclusions prove plastic buckling limits the buckling of cylindrical shells with large diameter-thick ratio and the strength damage appears before buckling failure.In this paper, the research contents and results lay a foundation for the feasibility of relying on friction to implement the whole installation of offshore wind turbine, and provide a reference for the design of the hoop.