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SUMMARY:The eXtended finite Element Method for 3D non-planar frictional cr
 acks - Theoretical aspects and application to fretting fatigue
DTSTART:20121213T121500
DTEND:20121213T131500
DTSTAMP:20260407T110934Z
UID:da7409135019f492ad34791af7b5c7751106769d68bacdbd841ccdf6
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Anthony Gravouil\nThree-dimensional crack growth simulat
 ions require both an accurate geometrical modeling of the crack and front 
 shapes and a precise quantification of interface displacement and traction
  fields. Tribological fatigue like rolling fatigue\, fretting fatigue invo
 lve three-dimensional crack problems in which the interfacial crack behavi
 or is mainly governed by complex sequences of contact/friction states. In 
 this context\, enriched finite element methods (coupled for instance with 
 a level set modeling of the possible non-planar crack shape) are very well
  suited to model discontinuous physical behaviors independently of a given
  initial mesh. These enrichments avoid the mesh compatibility of the crack
  with the bulk\, the remeshing and the field interpolation when dealing wi
 th crack propagation modeling. However\, many cases require to impose cons
 traints on the enriched interfaces: Dirichlet boundary conditions\, contac
 t or frictional interfaces\, etc... Unfortunately\, imposing these constra
 ints involves two drawbacks: On the one hand\, it imposes to discretize th
 e crack interface to address displacement and traction fields using interf
 ace elements based on bulk finite elements cut by the crack. Hence it invo
 lves a mesh dependency between the interface and the bulk. This work prese
 nts the key procedures to undertake the crack face contact problem when us
 ing X-FEM under a global-local approach. The use of the locally two-scale 
 approach in a three field weak formulation ensures that sufficiently refin
 ed crack faces can be incorporated into the numerical models\, avoiding an
  unaffordable refinement of the bulk mesh at the component level and thus 
 keeping the spirit of the X-FEM. The need of the stabilization for the sol
 ution in the contact tractions is evidenced\, especially for contact probl
 ems where sliding is important. For that purpose\, a dedicated non-linear 
 solver is introduced. A thorough numerical verification of the pro- posed 
 methodology is presented. The combination of the three-scale X-FEM model a
 nd the non-linear solver enables the accurate resolution of the crack face
  frictional contact with a low computational cost and good stability prope
 rties. The application of the procedure to a 3D fretting fatigue test is t
 hen presented. The correlation with experimental testing is performed\, ta
 king into consideration the actual crack resulting from the tests by means
  of automated 3D crack geometry reconstruction. The contact state evolutio
 n is presented and gives an idea of the potential of the methodology devel
 oped\, which is capable of analyzing several cracks simultaneously with hi
 gh accuracy while keeping a reasonable computational cost thanks to the mu
 lti-scale approach. Such an approach can also be applied to a wide range o
 f engineering applications implying complex frictional effects on 3D crack
  propagation.\n\nBio: Anthony Gravouil is Professor of Computational Mecha
 nics and Structural Engineering at INSA de LYON\, France. He has received 
 his degrees from Ecole Normale Supérieure de Cachan\, France (MS and Ph.D
 .). During his post-doc at Northwestern University (Chicago\, USA)\, he de
 veloped the Extended Finite Element Method coupled with level sets for 3D 
 crack propagation in collaboration with professor Ted Belytschko and Nicol
 as Moës. For 10 years\, his fields of research at LamCoS laboratory (INSA
  de LYON\, France) include the development of numerical methods efficient 
 and robust (X-FEM) for the simulation of two-dimensional and three-dimensi
 onal crack propagation without remeshing (dynamic crack growth\, fatigue c
 rack growth with confined plasticity\, tribological fatigue with contact a
 nd friction) in the team of professor Alain Combescure. These developments
  are made according to experimental validation (X-ray micro-tomography\, 2
 D and 3D digital image correlation) for the identification of 3D crack gro
 wth laws. A second field of research concerns the development of space-tim
 e multi-scale methods for two-dimensional and three-dimensional transient 
 nonlinear dynamics. The applications concern the simulation of crash and i
 mpact phenomena when multi-time scales effects occur. More recently\, he d
 eveloped reduced order modeling techniques related to these two areas: com
 putationally efficient 3D fatigue crack propagation numerical models\, spa
 ce-time reduced order models for transient dynamics and engineering applic
 ations with frictional contact.
LOCATION:GC C330
STATUS:CONFIRMED
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