xfem

3-D and 2-D Crack Growth Simulation

Hi,

Is it possible to use 2-D finite elements capable of accurately predicting all stresses (three dimensional stress state) for 3-D crack growth simulation?

Subramanian

Solver for XFEM

In the FEM book by KJ Bathe and also in the fem book by G.Dhatt, it is said the direct solvers are generally more convenient than iterative solvers and new versions of them include reordering and efficient use of skyline method. In contrast there are iterative solvers with capability to directly manipulate sparse format of matrices. I am now working on XFEM coding with C++ and don't know what type of solver would be the best for XFEM. the conditioning issues of matrices obtained from XFEM would be a difficulty for the choice of preconditioners.

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XFEM: crack tip function derivatives

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Hi,

I am using a X-FEM Matlab code found here http://people.civil.gla.ac.uk/~bordas/xfemMatlab.html"]http://people.civ...

In branch.m/branch_node.m (both functions of radius r and angle theta) crack tip fields are defined...and questions arise.

% Functions

f(1) = r2 * st2 ;
f(2) = r2 * ct2;
f(3) = r2 * st2 * ct;
f(4) = r2 * ct2 * ct;

The eXtended Finite Element Method (XFEM)

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Hello,

The aim of this writting is to give a brief introduction to the eXtended Finite Element Method (XFEM) and investigation of its practical applications.

Firstly introduced in 1999 by the work of Black and Belytschko, XFEM is a local partition of unity (PUM) enriched finite element method. By local, it means that only a region near the discontinuties such as cracks, holes, material interfaces are enriched. The most important concept in this method is "enrichment" which means that the displacement approximation is enriched (incorporated) by additional problem-specific functions. For example, for crack modelling, the Heaviside function is used to enrich nodes whose support cut by the crack face whereas the near tip asymptotic functions are used to model the crack tip singularity (nodes whose support containes the tip are enriched).