Numerical Simulation On Buckling Of Constrained Structures

Starting from the retrospection about research history and nowaday achievement about buckling of structure, both non-liner eigenvalue buckling problem and material, geometrical non-liner post buckling problem are simulated and calculated by finite element method. And, with help of ANSYS, commercial finite element software, we simulate the buckling and post buckling of common structures (beam, rectangular lamination, circle lamination, ellipse lamination structure) bridged by consecutive and discrete fibers. Comparing with the result from the structures with or without fibers in them, we prove the effect of the fibers of strengthen the stability of the structure. There are five parts of it:The first part begins with the theory of the stability of structure. Introduce the research history of buckling and nowadays achievement. After that, ANSYS is introduced to solve the problem, with the mothed of numerical simulation. Then, the backgroup, the scope and the basic method of research are given.The second part is starting from the liner eigenvalue buckling theory, and discusses non-liner eigenvalue buckling theory. Focus on the problem of ideal beam buckling problem, we show the solutions of it with ANSYS. As to non-liner eigenvalue buckling problem, axial beam with initial flaw is simulated by the second-stability-problem theory (collapse theory). Both the advantage and disadvantage are analysed about the two methods. After comparing with the solutions we got with the theory solution. Here, the reliability of the finite element anylysis softwares is proved.The third part, we add bridge fibers to the problem. The lamina on the structure is not simple buckling on loading, but bridged by fibers between them. Here, the fibers like springs, constrained on the structure and the lamina. The results of simulation prove that the fibers strengthen the structure, when the structure is loading with stress. The buckling of the structure is weakening by the fibers, so the structure is hard to destroy by buckling. This part, at first, we compare the results of beam with and without fibers, by changing parameters, we prove the strength-effect of structure bridged by fibers. And the elastic beam is researched too. Then, the buckling theory of retangular lamination is introduced, and simulates the buckling of it with or without fiber, compares the different buckling deformation pattern.The forth part leads us to the buckling of circle lamination and ellipse lamination. The buckling of the structure with initial flaw is simulated with the method used in the foregoing part. Still, the deformation pattern and the maximum deflection of the structure with or without the fiber are compared. The results just validate the effection of fiber.The last part is the summarization of the dissertation. A series of conclusions are here, and just try to think about the futher research.