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Modelling of Elastic and Plastic Deformation Fracture and Crack Propagation in 3D Problems Using Adaptive Finite Element Method

Moslemi, Hamid | 2010

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 40403 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Khoei, Amir Reza
  7. Abstract:
  8. Numerical methods in fracture and crack propagation problems usually involve high computational costs. Adaptive finite element method is one of the techniques which can be used to simulate the crack propagation with an acceptable accuracy. In this thesis, various constitutive models are implemented for simulation of fracture, including the linear elastic fracture mechanics, cohesive zone model and continuum damage mechanics. The fracture mechanical evaluation is performed on a general integral technique for non-planar curved cracks in LEFM. In the second model, a bilinear cohesive zone model is applied to implement the traction-separation law. The Lemaitre damage model is employed and the micro-crack closure effect is incorporated to simulate the damage evolution in the last model. In order to control the error of FE discretization, the standard superconvergent patch recovery (SPR) method is modified by the weighting parameter to achieve more realistic and accurate results, particularly at the boundaries and near the crack front. Adaptive finite element remeshing technique is implemented automatically at various stages of crack growth. Several numerical examples which can not be simulated in 2D domain are presented to illustrate the robustness and accuracy of proposed technique. It is shown how the proposed adaptive mesh refinement technique can reduce the value of estimated error considerably in 3D crack propagation problems.
  9. Keywords:
  10. Adaptive Finite Element Method ; Three Dimentional Crack ; Crack Propagation ; Continuum Damage Mechanics ; Elastic Deformation ; Plastic Deformation ; Linear Elastic Fracture Mechanics ; Cohesive Zone Model

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