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Simulation of Concrete Meso-Structure Within FEM/CDM Framework

Yghoobi, Mohammad Reza | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41569 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Vafai, Abolhassan; Shahbeyk, Sharif
  7. Abstract:
  8. Various theoretical studies have been developed to obtain a deeper understanding of concrete behavior lead to the concrete constitutive models in the macroscale. In these models, however, the microstructure of the concrete and its effects on the concrete behavior has not been taken into account.Several numerical approaches have been incorporated to determine the effects of concrete mesostructure on the overall behavior of concrete. They may be classified at least in three main groups. In the first group, Continuum finite element methods (FEM) equipped with interface elements is incorporated. Second group is to incorporate more efficient elements, such as lattice or truss elements, instead of conventional continuum elements. Researchers utilize conventional continuum FEMs as a third group.In this study, the mesostructure of concrete has been simulated using a 3D finite element model consists of two phases of mortar and coarse aggregates. A plastic-damage constitutive model is applied to the mortar. The numerical implementation of the plastic-damage model is presented and the validity of implementation has been investigated. The aggregates are assumed to behave in a linear elastic manner.In the next step, the effects of concrete microstructure on its failure are studied.For this purpose, the compressive meridian of concrete at failure, as the representative for concrete failure, is chosen. Then the effects of mortar parameters and aggregate volume fraction on concrete compressive meridian are analyzed.Finally, the alternatives for classical FEM which does not need any powerful mesh generator are studied. Extended finite elements (X-FEM) are chosen between the studied methods. Describing the X-FEM basics, its applicability is investigated
  9. Keywords:
  10. Concrete ; Microstructure ; Extended Finite Element Method ; Plastic-Damage Model

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