Morfeo2.1更新

Morfeo 2.1 功能列表

Friction stir welding

The modeling of the friction stir welding process is based on a two scales approach. At the local scale

of the tool, a fluid model predicts the flow around the tool and the distribution of the temperature

field.  This model can be coupled  a  global scale  computational model  of the whole workpiece. The

latter  uses  thermo-mechanical  classical  approach  to  predict  the  resulting  residual  stresses  and

distortions after welding. Post-processing to predict grain sizes is also available.

  Staggered thermo-fluid solution scheme at local scale:

   o  Eulerian formulation of thermal solver and mixed velocity-pressure formulation flow

solver

   o  Steady state and transient (using rotating frame of reference) flow solver

  Transient  thermo-mechanical  solution  scheme  at  global  scale  (similar  to  fusion  welding

model with additional dedicated boundary conditions; see hereafter for more details)

  Material modeling

   o  Viscoplastic (for fluid model, e.g.: Norton-Hoff)

   o  Elasto-viscoplastic (for mechanical model)

   o  Thermal properties (density, specific heat, conductivity, thermal expansion)

   o  Temperature dependent properties

  Metallurgical modeling

   o  Relevant models to FSW

  Account for thermal contact

  Account for heat generated by friction and viscous dissipation

  Velocity, surface flux and heat source boundary conditions specific to FSW

  Streamlines generation

  Imposition of volumetric flux along a circular trajectory in addition to linear one

  Parallel computation (both distributed (mpi) and shared memory (multi-threaded) )

Fusion welding

The fusion welding  process is modeled  with  a thermo-mechanical analysis at the global scale of the

workpiece. Depending on welding parameters (heat source shape and intensity, welds sequence etc),

the resulting residual stresses and distortions are predicted.

  Staggered thermo-mechanical coupling

  Material modeling:

   o  Elastic

   o  Elasto-(visco)plastic

   o  Thermal properties (density, specific heat, conductivity, thermal expansion)

   o  Temperature dependent properties

  Thermal analysis:

   o  Stationary and transient

   o  Convection

   o  Radiation (from a far distance)

   o  Specific heat flux for fusion welding

  Double ellipsoid

  Double elliptic cone

  Cylindrical

  Two  spheroidal  contributions  near  the  surfaces  and  a  conical  variation  inbetween

   o  Specific heat flux definition in a local frame moving along the welding trajectory

   o  Surface heat source

  Several ways for definition of welding trajectories

  Progressive activation of finite elements during the simulation

  Parallel computation (both distributed (mpi) and shared memory (multi-threaded) )

Machining

The modeling of the machining process is  performed at the scale of the workpiece.  Cutting surfaces

(for  3D  models)  corresponding  to  the  different  machining  passes  and  operations  and  an  initial

residual  stress  field  produced  during  the  preceding  manufacturing  process  (forging,  heat

treatment,...)  must be provided;  distortions resulting from  the  relaxation of residual stresses during

the removal of  the  material are  predicted.  The residual stress field at the end of the process is also

predicted.  Level-sets are used to implicitly  represent  the cutting surfaces.  This method enables the

simulation  of    multiple  passes  while  accounting  for  the  deformation  of  the  workpiece  during  the

process.

  Mechanical analysis

  Linear elastic materials

  Implicit cutting paths representation with level-sets (signed distance field with respect to the

cutting path)

  Robust and efficient level-set sign definition from the normals (3D problems; 2D interface) or

the tangents (2D problems; 1D interface) of the interface mesh;

  Dedicated to multi-pass machining simulation on complex industrial workpieces

  Parallel computation (both distributed (mpi) and shared memory (multi-threaded) )

  Remeshing along the iso-0 level.

Crack propagation analysis

Morfeo/Crack  is  a  software  product  for  the  computation  of  the  stress  intensity  factors  along  the

front of three-dimensional cracks and the prediction of crack propagation under fatigue loading. It

implements  the  extended  finite  element  method  (XFEM)  for  the  modeling  of  cracks  in  a  meshindependent  way.  The  stress  intensity  factors  are  computed  accurately  thanks  to  dedicated

enrichment  functions  which  improve  the  quality  of  the  solution  at  the  crack  front.  Moreover,

Morfeo/Crack offers unique algorithms for  modeling the propagation of multiple, 3D cracks with no

limitation on the crack shape.

  Enrichment  to  represent  singular  stress  field  around  crack  tip  and  discontinuous

displacement field across crack

  Stress Intensity Factor computation with domain integrals

  Crack propagation modelling with the Fast Marching Method

  Crack propagation model properties:

   o  Several propagation laws:  Paris (including temperature dependent), Elber, Forman,

Nasgro

   o  Optional crack propagation threshold

   o  Propagation controlled by either  the crack increment length  da  or a given load cycle

number dn

   o  Either single load case for a crack propagation with a load cycle defined with respect

to a load ratio coefficient or double load cases for a crack propagation with a non proportional load cycle

  Initial crack definition:

   o  Geometrical description

   o  Meshed surface

   o  Restart from a previous computation

   o  Multiple cracks definition

  Tailored quadrature methods around crack

  Inner pressure on crack faces

  Temperature-dependent elastic material with expansion, reference temperature and density

  Contact between crack surfaces provided a conform mesh is built

  Elasto-plastic analysis for stationary cracks:

   o  2D Stress Intensity Factors computation

   o  3D: Crack tip opening displacement

   o  3D: Crack tip opening angle