| The description of mechanical properties about concrete is a difficult problem in mechanics. The studies about it are going on by researchers. Some problems on mechanical parameters and size effects of concrete are studied in this dissertation. The main contents are as follows.(1) Three size effect laws are reviewed, analyzed and commented. They are Weibull statistical size effect law, Bazant size effect law and Carpinteri size effect law.(2) The micro-mechanical properties are studied by Random Aggregate Model.(3) Various size components are analyzed by Random Aggregate Model. It is showed that the concrete components have the characters of size effect. Then the analysis data are compared with Bazant size effect law and Carpinteri size effect law.(4) The affect factors to fracture energy of concrete are discussed. Then some statistical models are developed. The multi-factors statistical model in above models is a feasible and correct model. This conclusion is built on the basis of analysis.(5) The resource of fracture energy is studied. The size effect of fracture energy results in the change of fracture process zone in various size components.(6) A fractal model of fracture energy is built with fractal theory. The size of component and the fractal dimension of crack are involved in this model. The analysis to the model indicates it is a feasible and correct model.(7) A fractal model of SIF is also built with fractal theory. The analysis indicates it is a feasible and correct model.(8) The error of SIF is discussed too. Then an index to estimate error of SIF is advised. The analysis shows it is a feasible and correct parameter.Size effect, Numerical analysis, Statistical theory, Energy theory, Fractal theory...
|
PDF Full Text Request