3D crack propagation : X-FEM and mesh adaptation

by S. Géniaut, EDF R&D / AMA

A year after its release, the macro-command PROPA_FISS (for crack propagation) has faced the best teams in the domain.

Indeed, PROPA_FISS was evaluated on an industrial survey, as part of an international benchmark on crack propagation. This benchmark was proposed by Cenaero, SNECMA and EDF R&D in the ECCM 2010 conference held in Paris. The objective of this benchmark was to compare different methods for crack propagation (FEM, X-FEM…). Apart from the organizers, two other teams (ZENTECH and ONERA) participated. For its part, EDF R&D "competed" with a methodology combining X-FEM, level sets and mesh refinement with HOMARD, available in Code_Aster version 10.

At first sight, the results are encouraging and the discrepancies between the various teams are small. The mesh refinement procedure (command MACR_ADAP_MAIL) following the crack tip during propagation is efficient. The three available methods of the PROPA_FISS command were compared. It appears that the simplest method (method MESH) provides good results if the propagation is almost flat (no violent bifurcation) but problems remain when the crack front reaches an edge of the structure . The other two methods (SIMPLEX and UPWIND) are more robust and can overcome some of these problems.

Propagation for load n°1 (front view)	Propagation for n°1 (rear view)

Geometry of the part