Three Dimensional GFEM And Application In Concrete Structure Crack Problem

When strengthened, concrete becomes a quasi-brittleness material. It is one of the hot point of academe and engineering domain for crack analysis on concrete structure all the time. At present FEM (Finite Element Method) is widely used to simulate the concrete structure crack, but when FEM is applied to simulate the concrete crack there are many shortcomings such as poor computing efficiency and relatively low precision. In this paper, author applies GFEM (Generalized Finite Element Method) to concrete structure crack problem to find a new way to study this problem.In this paper, author establishes GFEM theory on three dimensional problem and apply GFEM to analyze nonlinear problem and to study concrete structure crack problem. In all, the following are the primary content:1. Summarize the study result of concrete crack simulation, discuss the mechanics of concrete crack. In the paper, appraise the several models on concrete crack and several numerical analysis methods. Point out the shortcoming of FEM on concrete crack analysis.2. Further demonstrate the basic idea of GFEM, deduce the corresponding formula on three dimensional problem. In theory illuminate the advantage of GFEM. Author compares it with FEM in precision and computing efficiency, by the actual example verifies GFEM the feasibility and the advantage.3. Extend GFEM into the nonlinear domain, develop GFEM program for the nonlinear problem . prove GFEM valid and feasible by the example of the thick cylinder bearing the uniform inner press.4. Apply the nonlinear GFEM to study the concrete crack problem, develop the corresponding program using the smeared crack model. In order to calculate the crack depth efficiently, author introduces the muti-layer model into crack problem .The purpose of this paper is to apply GFEM to make a research on concrete crack problem, so find a new way to the numerical simulation of concrete structure crack.