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XFEM2011 ECCOMAS Thematic Conference on Partition of Unity Enrichment and Applications

Dear colleagues,

Apologies for cross postings.

The second ECCOMAS Thematic Conference on the eXtended Finite Element
Method (XFEM) will take place in Cardiff (Cardiff University) in the
period 29 June - 1 July 2011. [see http://www.xfem2011.com for
details]

We would like to invite you and your students to submit original
research contributions in the area of partition of unity enrichment.
In particular, we welcome contributions to the following topics:

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

XFEM Error Estimation for Fracture- PhD Fellowship/Scholarship Centre Henri Tudor/Cardiff University

A PhD position is available at Centre Henri Tudor (Luxembourg) and Cardiff University (UK) on the simulation of crack propagation with adaptive extended finite element methods.

Candidates from any country are eligible. 

Please contact me for details.

Stephane

Angelo Simone's picture

Phd position in computational mechanics

A fully funded PhD position is immediately available in the area of multi-scale modeling of geomaterials within the research project "Failure of cohesive geomaterials: bridging the scales - GEOBRIDGE" at Laboratoire Sols, Solides, Structures - Risques (3S-R), Université Joseph Fourier, Grenoble, France.

Angelo Simone's picture

PhD position in computational mechanics

A fully funded PhD position is available in the area of multi-scale modeling of geomaterials within the research project Failure of cohesive geomaterials: bridging the scales - GEOBRIDGE at Laboratoire Sols, Solides, Structures – Risques (3S-R), Université Joseph Fourier, Grenoble, France. 

LOW-CYCLE FATIGUE CRACK PROPAGATION IN ABAQUS USING XFEM

 

Hi all,

 I´m traying to simulate a low-cycle fatigue crack growth in Abaqus 6.9 using xfem. My problem is to add the low cycle method to the xfem solution. 

I believe that the only current option for this would be to manually
create the loading curve and to do the analysis by a brute force
method but i may not be correct in this assumption however.

Please could someone explain a brief method.

i appreciate in advance.

 

 

Dear Omid and Sepehr

I think a non-zero entry in the stiffness matrix doesn't necessarily imply dependence of ith DOF on the jth DOF. This is the case also for standard FEM (without any enrichments). For example for a quadrilateral 2D element the x component of displacement has interaction with y component at each node, but as we know, two independent values of translation in x and y directions can

A Problem in Nature Of XFEM Approximation

There is a basic problem in NATURE of approximation of discontinuity in element using XFEM.I tried to illustrate that below:
for example, If you consider an element with strong discontinuity( like fracture or contact) which usually we use heaviside function as enrichment function. we expect two parts of element deform independently because of nature of problem.

In equation for approximation of this element we have two main parts. First  is 'regular' or 'standard' part which uses the standard shape functions of element and Second is the enriched part.

Post-doc Smoothed XFEM for Nano-CMOS Semi-Conductors Glasgow/Cardiff University

A one-year post-doc is available in conjunction with

1) Prof. Asenov, University of Glasgow

2) Dr. Bordas, University of Glasgow/Cardiff

 to study the behaviour of nano-CMOS semi-conductors.

Please write to stephane dot bordas at g ma i l dot com 

 for details with your:

1) CV

2) Three references

3) a statement of why you are qualified and interested in this position

 You should

1) have a strong background in finite element methods

2) excellent programming skills in MATLAB and C++

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.

X-FEM implementation in Abaqus

Dear all,

Just in case it is of interest to some of you, we provide links to three postprints related to our Abaqus implementation of the X-FEM. The latest is an "article in press" in Eng Frac Mech where we explain the essentials of the implementation and provide a link to the source code for the Abaqus computation. Note that the implementation is limited to 2D and the pre-processing code needed for element subdivision is not provided.

UK Newton Post-Doc Fellowship in Computational Mechanics

 
Dear All,

A new multi-million pound initiative to fund research collaborations and improve links between UK and overseas researchers has been launched.

The Newton International Fellowships aim to attract the most promising, early stage, post-doctoral researchers working overseas, who do not hold UK citizenship, in the fields of humanities, engineering, natural
and social sciences.

MSc+PhD position Fully Funded -- Massively parallel biomechanics simulation of brain surgery on HECToR

High Performance Computing MSc+Ph.D. position available at the
University of Glasgow on Massively Parallel Brain Surgery Simulation
with the extended finite element method (XFEM and FleXFEM)  (University
of Glasgow) -- funding body is EPSRC.

One year MSc in HPC in Edinburgh (all costs covered by funding) + 3 year Ph.D.  and access to HecToR,
one of the world's largest super-computer, including training with
experts in massively parallel simulation (10,000+ processors).

Three MSc + PhD positions available on Multi-Scale and Biomechanics Parallel Simulations on HECToR.

Dear all,

 Three positions are available for a unique MSC + PhD on massively parallel processing for computational mechanics in the field of multi-scale, XFEM and biomechanics. 

 Details here:  http://www.gla.ac.uk/departments/civilengineering/postgraduatestudy/rese...

 Experience in Finite Elements or numerical methods and mechanics is *essential*. Please do not apply if you do not have this experience.

Ettore Barbieri's picture

The Future of Meshless Methods

I joined imechanica almost a year ago and I've been frequently following its interesting discussions, even the most animated ones. I think that a place like this is ideal to foster the exchange of ideas in the scientific community;

Moreover it is fantastic as a simple student like me can interact and easily ask questions to the most important researcher in the field of mechanics.

A Ph.D.+MSc Position on Brain Surgery Simulation by XFEM and FleXFEM

High Performance Computing MSc+Ph.D. position available at the University of Glasgow on Massively Parallel Brain Surgery Simulation with the extended finite element method (XFEM and FleXFEM)  (University of Glasgow) -- funding body is EPSRC.

One year MSc in HPC in Edinburgh (all costs covered by funding) + 3 year Ph.D.  and access to HecToR, one of the world's largest super-computer, including training with experts in massively parallel simulation (10,000+ processors).

Crack Propagation using XFEM ( What happens to dof's corresponding to enriched nodes)

I am working on crack propagation . I am trying to figure what factors should be taken into account when the crack is being propagated using XFEM.

I am especially interested to know what happens to the additional dof's corresponding to enriched nodes. Once the crack is propagated and crack tip is at new location , we add new dof's corresponding to enrichment functions , but what happens to the information stored by the dof's of previous enriched nodes,do we forget them altotgether , or do we map it to the new enriched nodes?

XFEM: crack tip function derivatives

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;

eXtended Finite Element Method: Short Course Notes

I taught a short course some time ago on the eXtended Finite Element Method, and thought many people would find the notes useful.  

So I've posted them here, in .mov format (as exported with the Apple software keynote).  The advantage of this format is that, when you click on one of the .mov files, it should open a separate browser.  Clicking in the window will advance the slide. This way you see all the movies, etc, as well as the sequence as it appears when I gave the talk.  There is a way to add audio to this format as well - something I may pursue in the future.  

Robert Gracie's picture

A new finite element method for dislocations based on interior discontinuities

Comments and feedback of the following paper would be appreciated.

Abstract:

A new technique for the modelling of multiple dislocations based on introducing interior discontinuities is presented. In contrast to existing methods, the superposition of infinite domain solutions is avoided; interior discontinuities are specified on the dislocation slip surfaces and the resulting boundary value problem is solved by a finite element method. The accuracy of the proposed method is verified and its efficiency for multi-dislocation problems is illustrated. Bounded core energies are incorporated into the method through regularization of the discontinuities at their edges. Though the method is applied to edge dislocations here, its extension to other types of dislocations is straightforward.

phunguyen's picture

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).

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