Study On Three Dimension Random Aggregate Model Of Dam Concrete

The analysis and research of meso-mechanics is one of the popular methods of current researching on the mechanic behaviors of concrete materials. In the meso-mechanic method, Concrete is taken as a type of three-phase composite material comprising mortar matrix, aggregate and bond between matrix and aggregate. Using nonlinear finite element method numerical simulation is executed to present the damage failure process of concrete specimens considering the heterogeneity of various phase of concrete.The mechanical behaviors of concrete are directly related to its grade and aggregate content. A good model of the full-grade aggregate concrete with high aggregate content is precondition to successfully execute concrete meso-mechanical simulation, So that the main work in the dissertation is focused on the following study concerning the random aggregate model of dam fully-graded concrete:(1) Based on the topology of spherical aggregates, an algorithm of the random convex polyhedron aggregate model was presented considering the actual aggregate content, grading, and aggregate shape, and corresponding FORTRAN program was developed to generate random convex polyhedron aggregate. Further, the codes of the meso-scale structured finite element grids of concrete are developed.(2) The FORTRAN program to generate random convex polyhedron aggregate based on the topology of spherical aggregates and the codes of the meso-scale structured finite element grids of concrete are developed. By means of the oriented object technique of VB on the window platform, a FORTRAN program and MATLAB software can be called to generate and visualize the aggregate models. Moreover, the data format required and the way how to plot the finite element map by means of GID software are introduced.(3) Investigate the method of optimizing meshes by which two dimension finite element grids of meso-scale can be improved.(4) The three dimension parallel numerical computation of the wet-sieved concrete specimen was executed successfully to verify the program of random convex polyhedron aggregate.