ABAQUS XFEM Tutorials

Introduction

Abaqus 6.9 has introduced the ability to model cohesive cracks in the XFEM¹ framework using a version of the superimposed element formulation originally introduced by Hansbo². This method was later used by Song³ as a means to more conveniently introduce XFEM into the traditional FEM framework. For more information please see the Abaqus 6.9 Webinar (63:15). For the announcement that contour integrals will be available in 6.9-EF, please see the Abaqus 6.9-EF Webinar (12:24).

Some of the above limitations are being addressed by Global Engineering and Materials, Inc. who is developing their own XFEM toolkit for Abaqus, specifically fatigue crack growth and by Cenaero who introduce expanded functionality to the native Abaqus implementation of XFEM. Also, Giner⁴ implemented XFEM in Abaqus through the use of user element subroutine and custom pre-processing tools.

Limitations

What follows is a brief list of the current limitations with regards to the use of XFEM within Abaqus taken from the Abaqus 6.9 Update Seminar⁵.

1. Only the STATIC analysis procedure is allowed.

2. Only linear continuum elements are allowed (CPE4, CPS4, C3D4, C3D8) with or without reduced integration.

3. No parallel processing of elements.

4. No contour integrals for cracks (available in Abaqus 6.9-EF⁶ and later for linear brick and tetrahedron elements).

5. No fatigue crack growth.

6. Domain must contain single or non-interacting cracks.

7. Only one crack may exist within a particular element.

8. A crack may not turn more than 90 degrees within a particular element.

9. A crack may not branch.

10. Not available in Abaqus/Explicit.

Tutorials

Each tutorial will be given it's own page in order to keep things in a relatively neat and tidy fashion. Each page will include a step by step tutorial about how to build the model within Abaqus/CAE and include input and output files which will be available for download. All tutorials have been created and tested in Abaqus 6.9-EF. I do not currently have access to Abaqus 6.10 for testing in that environment. A list of examples follows.

1. 2D Static Edge Crack

2. 2D Static Crack with Temperature

3. 2D Crack Growth in Presence of a Hard Inclusion

4. 2D Crack Initiation

5. 3D Static Edge Crack

6. 3D Static Edge Crack SIF Convergence Study

7. 3D Static Penny Crack

Please feel free to provide feedback on the available tutorials.

You can find additional tutorials by joining the Simulia Learning Community.

References

1. Moes, N., Dolbow, J., Belytschko, T. (1999) "A finite element method for crack growth without remeshing," International Journal for Numerical Methods in Engineering, 46, 131-150.

2. Hansbo, A., Hansbo, P. (2004) "A finite element method for the simulation of strong and weak discontinuities in solid mechanics," Computer Method in Applied Mechanics and Engineering, 193, 3524-3540.

3. Song, J., Areias, P., Belytschko, T. (2006) "A method for dynamic crack and shear band propagation with phantom nodes," International Journal for Numerical Methods in Engineering, 67, 868-893.

4. Giner E., Sukumar, N., Tarancon, J.E., Fuenmayor, F.J. (2009) "An Abaqus implementation of the extended finite element method," Engineering Fracture Mechanics, 76, 347-368.

5. (2009) "Extended Finite Element Method (XFEM)," Abaqus 6.9 Update Seminar, Dassault Systemes.

6. (2009) "Abaqus 6.9 - Extended Functionality (EF) Overview," Abaqus 6.9-EF Update Webinar, Dassault Systemes.