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Safdar Abbas

Contact

Safdar Abbas, M.Sc.
Aachen Institute for Advanced Study 
in Computational Engineering Science (AICES)
RWTH Aachen
Schinkelstr. 2
52062 Aachen

Tel. (0241) 80 99140
Fax (0241) 80 628498
Email abbas [at] aices.rwth-aachen.de

Education

since 11/2007Postgraduate Position at Aachen Institute for Advanced Study in Computational Engineering Science (AICES), RWTH Aachen
10/2005 - 10/2007Master Courses in Computational Science in Engineering (CSE), TU Braunschweig, Germany
03/1996 - 06/2000Bachelor Degree in Civil Engineering, University of Engineering and Technology, Lahore, Pakistan

Professional Career


12/2001 - 08/2005
Work as a software testing engineer at Trivor Software Consultants,

Islamabad, Pakistan (an offshore office of the Bentley Systems inc. USA)

Research Interests

High Gradient XFEM for Fracture Mechanics:

The extended finite element (XFEM) is a numerical method to simulate discontinuities and singularities. The XFEM has been mostly used in the field of fracture mechanics. Its application to fracture problems involve enriching the approximation space with appropriate enrichment functions. These enrichment functions include the a priori knowledge about the solution behavior into the approximation space. In the case of fracture mechanics, there are two solution characteristics that need to be included in the approximation space. The first is a discontinuity along the crack path. The second is the stress concentration in the near-tip region. For the discontinuity along the crack path, the approximation space is enriched by a step enrichment function. In the near-tip region, the enrichment function is based upon the asymptotic solution in that region. This dependence on the asymptotic solution makes the crack-tip enrichment function dependent on a particular fracture model. For someone who needs to concentrate on modeling issues, it becomes an additional task to create the appropriate enrichment function. Additionally in the case where fracture models with unknown analytical solutions are considered, it becomes often impossible to find the appropriate enrichment function. In this work, a model independent approach is proposed and investigated in order to find a set of model-independent enrichment functions that are valid independent of the fracture model.


Publications

Dissertation

  • S. Abbas: "A Third Order Accurate Semi-Implicit Runge-Kutta Method for the Compressible Navier-Stokes Equations", M.Sc Thesis at the Institute of Aerodynamics and Flow Technology, DLR (German Aerospace Center), Braunschweig, October 2007. Click Here

Publications in Journals and Books

  • Richard Dwight, Ursula Mayer and Safdar Abbas : High-Order Time-Accuracy using Approximate Jacobians for the Compressible Navier-Stokes Equations. Modern Techniques for Solving Partial Differential Equations, Koninklijke Vlaamse Academie van Belgie, 2008. Editors: Chris Lacor, Eli Turkel. ISBN 978-9-065-69041-8. Click Here
  • S. Abbas, A. Alizada, T.P. Fries: The XFEM for high-gradient solutions in convection-dominated problems, Internat. J. Numer. Methods Engrg. 2010; 82:1044--1072. Click Here
  • S. Abbas, A. Alizada, T.P. Fries: Model-independent approaches for the XFEM in fracture mechanics, Internat. J. Numer. Methods Engrg., submitted. Click Here

    Conference Proceedings

    • S. Abbas, A. Alizada, T.P. Fries: The extended finite element method for high-gradient solutions, Proceedings of the ECCOMAS Thematic Conference on Extended Finite Element Methods (XFEM 2009) (T.P Fries, A. Zilian, Eds.), Aachen, Germany, Sep. 2009. Click Here
    • Safdar Abbas and Thomas-Peter Fries, A unified enrichment scheme for fracture problems, 2010 IOP Conf. Ser.: Mater. Sci. Eng. 10 012045. Click Here

      Conference Presentations

      • S. Abbas, T.P. Fries: XFEM as an alternative for the classical h-refinement, 10th U.S. National Congress on Computational Mechanics, Columbus, Ohio, USA, July 2009. Click Here
      • S. Abbas, A. Alizada, T.P. Fries: The extended finite element method for convection-dominated problems, 3rd GACM Colloquium on Computational Mechanics in Hannover, Germany, Sep. 2009. Click Here
      • S. Abbas, A. Alizada, T.P. Fries: The extended finite element method for high-gradient solutions, ECCOMAS thematic conference on extended finite element methods (XFEM 2009) in Aachen, Germany, Sep. 2009. Click Here
      • S. Abbas, T.P. Fries: High gradient enrichment functions for crack propagation in cohesive and cohesion-less cracks, IV European Conference on Computational Mechanics (ECCM), Paris, France, May 16-21, 2010. Click Here
      • S. Abbas, T.P. Fries: A unified enrichment scheme for fracture problems, 9th World congress on computational mechanics (WCCM 2010) in Sydney, Australia, Jul. 2010. Click Here