Study On Dam Stress Determination Based On Adaptive FEM And Plane FEM Stability Analysis For Xiaowan

Adaptive finite element method, including error estimator and adaptivemesh refinement technology, can effectively improve the accuracy of finiteelement analysis, so that can increase the realiability of the result of finiteelement method. Msc Marc Program has 2D and 3D remeshing function.Systematic study and comprehend on the primary principle of adaptive finiteelement method are carried on. And then, by using Msc Marc Program,adaptive finite element method is applied to study on dam stresssdetermineation and is combinated with arc length method to solve plastic limitload when structure would be destroyed. In present thesis, some conclusions are obtainted. Hierarchy meshstructure is often used in adaptive finite element analysis, and should beexpressed by dynamic data structure, such as bin-tree. The posterior errorestimator is varied in according to adaptive mesh refinement strategy using inthe analysis. The quality of error estimator is sensitive to some factors, such astopology, whether or not mesh is optimized or the smoothness of exactsolution. Analysis shows that Zienkiewicz-Zhu error estimator based onSuper-convergence theory has the best result. Among automatic meshgeneration methods, quadtree method has advantage in local mesh refinement.All above make clear that how computational methods and process foradaptive finite element method are carried on and which error estimator andautomatic mesh generation algorithm are reasonable in engineering analysis. Inaddition, adaptive finite element method is used to acquire limit load with thehelp of arc length method, and is used to study the problem how to determinethe FEM stress. Result show that stress under the control of given error limitcan be introduced, and error limit as a propositional zero dimension number5% can be used in analogy between project and project. - II -Another part of this thesis concerns the detailed procedure of planestability analysis for Xiaowan Arc Dam. According to the geologic conditionof this project, bottleneck of the project is found by elastictoplastic FEManalysis and overloading analysis. Then comparative study of different layoutof reinforcement is carried on. In the end, we propose some more effectivelayout of reinforcement. In addition, limit load under overloading obtainted byusing adaptive finite element method and arc length method is close to theresult of plane mode model test.