Three Dimension Lattice Modelling Of Tensile Fracture Of Concrete In Multiscales

Chloride diffusion in concrete which has got damaged is a key problem for the durability design. In this paper, a numerical model in multiscales is established to study the tensile fracture of concrete, and the development of crack in the model is analyzed. Using lattice model for its general properties of the fracture and the ion transport to sduty the transport properties of chloride ions in the damaged concrete much more easily. The fracture situation of cement, mortar and concrete under tensile load are studied. The main point of this paper is to study the interface transition zone at different scales, and using the result in the higher order model as the key point to improve the whole multi-scale models. By using three dimensional random lattice finite element model and random aggregate model of concrete, cement material under tension are discussed and results are as follows.Establish a model of concrete under different scales, including: at the microscopic scale, using HYMOSTRUC3 D to construct the heterogeneous cement lattice model based on the hydration, and according to the angle to build different interfacial transition zone models to solve the general model only decrease the strength simple; in the meso scale using random aggregate model to construct the mortar model and concrete lattice model.Programming with MATLAB to complete the random aggregate model and using sparse matrix partitioned matrix and some other advanced numerical technique. In the program, using preconditioning conjugate gradient method to operation the super large finite element system of lattice models.Simplified the analysis steps of lattice fracture model to save counting time, applying strain to the model and removing all the broken bar out. Got the stress-strain curve from the model. From the results, the strain step we applied to the model may greatly influence the curve we got. We also get the development and distribution of cracks in the models from the picture we got from our program, and the cracks happened as we expected, especially in the interfacial transition zone model.