Numerical Simulation On Buckling Of Constrained Plates

This thesis reviews the research history and current achievements about delamination buckling of composite structures, and both basic principles of finite element method and calculation methods are explored to calculate structural stability. For the rectangular and circular delamination constrained buckling, as the limitation of theoretical solution, we take advantage of finite element analysis software ANSYS to simulate this phenomenon. This thesis is divided into five parts:The first part begins with the significance of this study, reviews the research history and current achievements about structural stability of composite delamination problems from one-dimensional to two-dimensional, and clarifies the backgrounds and main research contents of this thesis.The second part describes the basic concept of buckling, the theory of linear eigenvalue buckling and the characteristics of nonlinear buckling.The third part explores the finite element analysis software ANSYS to simulate constrained buckling of rectangular plates (delamination of composites) under static state and considering large deformation. In order to simulate constraints, fibers are introduced to bridge between base and delamilation. Here, the fibers are assumed to provide continuous, linear restoring traction's opposing the deflection of the delaminated layer. For the buckling of rectangular plates, taking different aspect ratio into account, simulated results show that the critical load of delamilation buckling is greatly enhanced taking the fiber bridges into consideration and decreases dramatically while delamination length increases; the number of half-wave increases as the increment of delamination length and the enhancement of fiber bridge stiffness; taking different boundary conditions into account, simulated results show that the more constraints, the greater the critical load, the more the half-wave number; taking discrete fibers into account, comparison with the continuous fibers, results show that under the action of discrete fibers, critical load is less than that under the action of continuous fibers, and with the increase of fiber bridge stiffness, critical load increment is not so significant as under continuous fiber bridge.The forth part explores the finite element analysis software ANSYS to simulate constrained buckling of circular delamination under different load cases. From the simulation results we can see, fiber bridges can improve the critical buckling load and improve the carrying capacity of structures. The critical load of delamilation buckling is greatly enhanced as the increase of fiber bridge stiffness. The relationship of critical buckling load and fiber bridge stiffness are approximately linear. The greater the fiber bridge stiffness, the smaller the buckling region.The last part is the summarization of the thesis. A series of conclusions are made, as well as the follow-up study of prospects.