Evaluation of Stress Intensity Factor of a Bi-material Interfacial Crack Using Extended Finite Element Method

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Veisi, Hossein | 2012

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 44416 (45)
University: Sharif University of Technology
Department: Aerospace Engineering
Advisor(s): Adib Nazari, Saeed
Abstract:
In this study, Interfacial crack is modeled by the extended finite element method (XFRM) in order to evaluate the stress intensity factors for interface crack problems. These problems have crack edge discontinuity, material interfaces and singularity at the crack tip, which is inappropriate to finite element (FEM) mesh. Furthermore, around crack tips and interface edge, extremely fine discretization is required to achieve reasonable accuracy. All these factors increase the time and cost of the FEM solution. Recently the extended finite element method is developed and applied to interface fracture problems. In the XFEM, special enrichment functions are added to the finite element displacement approximation in order to simulate strong and weak discontinuities. This enables the bi-material domain to be modeled without explicitly meshing the interface or crack. A numerical code, based on XFEM method was developed and results compared with those of FEM. Results show that the XFEM method has a better acurecy and it overcome the weaknesses of the FEM
Keywords:
Stress Intensity Factor ; J-Integral ; Extended Finite Element Method ; Bi-Materials

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