Application of Extended Finite Element Method (XFEM) to Stress Intensity Factor Calculations

Author(s):  
Do-Jun Shim ◽  
Mohammed Uddin ◽  
Sureshkumar Kalyanam ◽  
Frederick Brust ◽  
Bruce Young

The extended finite element method (XFEM) is an extension of the conventional finite element method based on the concept of partition of unity. In this method, the presence of a crack is ensured by the special enriched functions in conjunction with additional degrees of freedom. This approach also removes the requirement for explicitly defining the crack front or specifying the virtual crack extension direction when evaluating the contour integral. In this paper, stress intensity factors (SIF) for various crack types in plates and pipes were calculated using the XFEM embedded in ABAQUS. These results were compared against handbook solutions, results from conventional finite element method, and results obtained from finite element alternating method (FEAM). Based on these results, applicability of the ABAQUS XFEM to stress intensity factor calculations was investigated. Discussions are provided on the advantages and limitations of the XFEM.

2012 ◽  
Vol 166-169 ◽  
pp. 2995-2998
Author(s):  
Geng Chen ◽  
Tao Xu ◽  
Qiang Xu ◽  
Lin Bu

The principle of the structure of displacement function, the establishment of governing equations, level set method were briefly outlined in this paper. Numerical simulations on three dimensional single edge notched specimens with different crack length in tension were performed using Abaqus software based on extended finite element method (XFEM), the stress intensity factor at static crack front was analyzed and the simulated results were in good agreement with analytical solutions. Numerical simulations in the present paper indicated that the extended finite element method is very suitable to deal with nonlinear fracture problems.


2012 ◽  
Vol 232 ◽  
pp. 686-690 ◽  
Author(s):  
Benmessaoud Abdelkader ◽  
Badaoui Mohamed ◽  
Hachi Brahim El-Khalil ◽  
Nehar Camellia Khaira ◽  
Guesmi Mohamed

The aim of this paper is the determination of the evolution of the modal stress intensity factor (MSIF) for a non-propagating crack subjected to dynamic loading using the extended finite element method (X-FEM). The main advantage of this method coupled with the modal analysis is its capability in modeling cracks independently of the mesh and in a reduced computational time compared to the finite element method coupled with dynamic iterative method. The proposed procedure is applied to a reference problem (cracked plate). The MSIFs obtained agree well with those found by indirect boundary element (IBEM), weight function and Newmark’s explicit methods.


2010 ◽  
Vol 13 (4) ◽  
pp. 51-63
Author(s):  
Hoa Cong Vu ◽  
Dat Cong Nguyen

Finite element method is a very powerful numerical method to predict and model mechanical behavior of material and structure. However, in some cases finite element method is more complicated like the modeling of moving discontinuities, hence the need to update the mesh to match the geometry of discontinuity. Extended finite element method (XFEM) allows us a new technique to modeling crack independently of the mesh; hence it is no need to remesh during propagation of the crack. In this paper, an extended finite element method is used to calculate stress intensity factor. It’s important parameter when we predict the direction of crack in the event of crack stops propagation.


2014 ◽  
Vol 25 (1) ◽  
pp. 4-25 ◽  
Author(s):  
Heng Wang ◽  
Zhanli Liu ◽  
Dandan Xu ◽  
Qinglei Zeng ◽  
Zhuo Zhuang

The shielding and amplification effects of transverse array of microcracks on a main crack are investigated using extended finite element method. The interaction between macrocracks and microcracks is quantitatively characterized in terms of the stress intensity factor which is calculated by the interaction integral method and the complete stress field in the entire domain could be given without remeshing. Various distributions of microcracks with different number, location, and density are considered. For a microcrack collinear to the main crack, the numerical results agree quite well with the analytical solution. Interestingly, the shielding and amplification effects display periodicity when the main crack is placed inside the microcrack rows. In particular, the minimum stress intensity factor of the main crack which refers to the maximum shielding effect is primarily determined by the nearest microcracks. However, the maximum stress intensity factor is largely affected by the distribution and density of microcracks and even could be turned from enhancement to shielding. The results are consistent with the microcrack-toughening phenomenon observed in the experiments and are meaningful for the design of new microstructure-toughening materials.


2015 ◽  
Vol 9 (1) ◽  
pp. 887-891
Author(s):  
Xinya Chen ◽  
Zhen Chen ◽  
Yang Zhao

Extended finite element method (XFEM) is the most effective numerical method to solve discrete mechanical problem. Crack growth problem of two-dimension finite length rectangle panel is researched based on Abaqus XFEM frame. Stress intensity factor is obtained respectively by theoretical calculation and XFEM simulation, which proves reliability of XFEM and the software.


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