Talk on Apr 25, 2013

Thursday, Apr 25, 2013 02:00 pm

Quasi-static crack growth: Models and numerical simulation with XFEM

M.Sc. Katja Hanowski (IGPM, RWTH Aachen)

The failure behavior of materials is of importance in many engineering applications,
such as the lifetime prediction of train wheels or the safety of geological radioactive
waste disposals. The reason for the failure of a specific material is the formation and
propagation of cracks in the predam- aged material.
The pioneering theory concerning the propagation of cracks was developed by A. A.
Griffith in the 1920’s.  He formulated a theory connecting the mechanical properties
of elastic cracked bodies and crack propagation by stating that a crack remains sta-
tionary if the energy of the mechanical sys- tem is minimal.  Based on Griffith’s idea
new variational models have been developed within the last fifteen years.  Although
the existence of solutions to the model-dependent notions of crack growth problems
can be prooved, none of these models is fully satisfactory.   A breakthrough in nu-
merical modelling crack growth processes has been made by the development of the
eXtended finite element method (XFEM). The XFEM approach over- comes problems
of standard finite element approximations like the need to adapt the mesh to the dis-
continuities of the solution of the mechanical problem.  It turns out that the XFEM
approach can be easily coupled with levelset methods to localize and propagate the
The first part of this talk is a review of the basic concepts of fracture me- chanics
and an introduction to the variational approach to fracture. Basic ideas and results of
the variational models are compared with those of the mechanical theory. The second
part of this talk includes the presentation of simple model for the simulation of crack
growth processes and the dis- cretization of this approach with XFEM and levelset
methods. Numerical examples are used to illustrate this procedure.

Time: 02:00 pm

Location: Room 149, Hauptgebäude, RWTH Aachen, Templergraben 55, 52056 Aachen