Studies On Random Aggregate Model And Damage Model Of Dam Concrete

In meso-level, concrete is taken as a type of three-phase composite material comprising mortar matrix, aggregate and bond between matrix and aggregate. Concrete mechanical behavior is directly related to its grade and aggregate content. A meso-structure model which can reflect the configuration of meso-structure of concrete and damage evolving under load is precondition to successfully execute concrete meso-mechanical simulation.Two parts of the main work in the dissertation include the packing technique of random aggregates of dam concrete and the investigation on damage parameters and their evolving relation of dam concrete and various phrase of meso-structure. The details as followed:1.Summarize and analyze the methods of meso-mechanics of concrete and researching documents on the theory of damage of concrete;2.Based on the packing approach of spherical aggregates, a method generating polygon aggregate model of concrete was presented, by which the codes of aggregate packing and meso-meshes of finite element plotting were designed taking into account the actual aggregate content, grading, and aggregate configuration.3.Numerical simulations of the flexural process of the trisection specimens of concrete were executed, as well as the influence of configuration of aggregates on computing results was analyzed, by which showed that the method proposed is valid and feasible.4. Ideal elastic-plastic damage evolving model was suggested considering damage retrieval under load removing. Back-analysis method and computing program of damage parameters by the curve of stress-strain by uniaxial tension and compression test was made out.5.By the damage evolving relation proposed the flexural process of the trisection specimens of wet-sieved and fully-graded concrete was numerically simulation.