Post on 13-May-2018
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Numerical Simulation of the Numerical Simulation of the Friction Stir Welding Process Friction Stir Welding Process using Lagrangian, Eulerian & using Lagrangian, Eulerian &
ALE ApproachesALE Approaches
Simon GUERDOUX Simon GUERDOUX andand Lionel FOURMENTLionel FOURMENTCEMEF, Ecole des Mines de Paris, FranceCEMEF, Ecole des Mines de Paris, France
TracyTracy NELSON, Michael MILES NELSON, Michael MILES andand Carl SORENSENCarl SORENSENBrighamBrigham Young Young UniversityUniversity, USA, USA
OverviewOverview
BackgroundBackgroundThe Friction Stir Welding ProcessThe Friction Stir Welding ProcessModeling of FSWModeling of FSW
Numerical models : Numerical models : FFORGEORGE33®® & T& THERCASTHERCAST®®
Modeling and experimental resultsModeling and experimental resultsPlunging phase : comparison between Plunging phase : comparison between experimental and numerical resultexperimental and numerical resultWelding phase :Welding phase :Lagrangian / Eulerian simulations capabilitiesLagrangian / Eulerian simulations capabilitiesALE formulation and first resultsALE formulation and first results
Future workFuture work
BackgroundBackground
The ProcessThe Process
Friction Stir Welding ProcessFriction Stir Welding ProcessPatented in 1991 by TWIPatented in 1991 by TWIA solidA solid--state joining processstate joining processPotential commercial and military usersPotential commercial and military users
•• aerospaceaerospace•• automotiveautomotive•• marinemarine
Capable of joiningCapable of joiningaluminum,steel, aluminum,steel, stainless steelstainless steel
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
Different main phases of FSWPDifferent main phases of FSWP
Plunging phase Dwelling phase :Plasticization
Welding phase
Advancing side
Retreating side
Weld joint
ωαF
ωω
vplunge
z
x
z
y
z
x
yPlane (y,z)Plane (x,z)
vadvance
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
Modeling of FSWModeling of FSW
Motivation:Motivation:
Predict material flow: try to minimize heat Predict material flow: try to minimize heat input, and eliminate defectsinput, and eliminate defects
Use to develop better tooling designsUse to develop better tooling designs
Predict mechanical properties of weld:Predict mechanical properties of weld:flow & thermal historyflow & thermal history
=> mechanical properties and eventually => mechanical properties and eventually microstructuremicrostructure
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
Approaches in literatureApproaches in literature
CFD approach: obtain information on CFD approach: obtain information on material flow, but neglect free surface material flow, but neglect free surface deformation and effect of deformation historydeformation and effect of deformation history
Lagrangian FE: Lagrangian FE: •• use analytical heat source and apply a use analytical heat source and apply a
compressive stress along the weld line; calculate compressive stress along the weld line; calculate residual stressesresidual stresses
•• simulate material flow, including heat from friction simulate material flow, including heat from friction and material deformation; requires complex and material deformation; requires complex remeshingremeshing
Arbitrary Lagrangian Eulerian (ALE) FE: can Arbitrary Lagrangian Eulerian (ALE) FE: can simulate flow and include heat from friction simulate flow and include heat from friction and deformation; avoids degeneration of and deformation; avoids degeneration of mesh; allows for deformation of free surfacemesh; allows for deformation of free surface
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
Numerical ModelsNumerical Models
• Hot, warm, and cold forging (FORGE3® )Filling and cooling of foundry parts (THERCAST®)
•3D thermo-mécanical computation
• Lagrangian (FORGE3® ) and /or ALE(THERCAST®) Finite Element Formulation
• Automatic Remeshing
⎪⎩
⎪⎨⎧
=−+∇−∇=−+∇
=−=
0..
03div)(tr vp
γgsγgσ
vε
ρρρρ
α
p
T&&Incompressibility and equilibrium
+ B.C.
FFORGEORGE33®® & T& THERCASTHERCAST®®
( )⎪⎪⎩
⎪⎪⎨
⎧
=
=+=
+=−
Iε
εIσs
εεε
T
Kp TmT
&&
&&
&&&
α
ε εε
th
vp1
),(
thvp
),(32
Pure viscoplastic behaviour (firstly) with thermal couplingStrong form of the mechanical problem :
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
( )extrc TThT +=⋅∇− nk
» Heat transfert by convection/radiation :
( ) gtool
tooldc v.τTThTbbbk
+++−=⋅∇− n
» Conduction with tools and heat due to friction :
Heat Sources
Norton friction equation :( )⎪⎩
⎪⎨⎧
−−−=Δ
ΔΔ−=<−
ababbaba
1),(f
).()(avec
alors0si f
nnvvvvv
vvτ
g
gp
gTn Kσ εα
aΩ
bΩabΩ∂ abδ
Contact equation :
⎪⎩
⎪⎨⎧
−−≈
≤+
+
Δt).(δδ
δ0tab
tb
ta
tab
Δttab
Δttab
nvv
0Δtδ
).(tabt
abtb
ta ≤−− nvv
ε:σ &&& ==∇− W avec ;Ω dans W)(dtdTc Tkdivρ
Heat Equation
+ B.C.
Strong form of the thermical problem :
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
•• Time Time discretisationdiscretisation
•• NewtonNewton--RaphsonRaphson algorithmalgorithm
•• Preconditioned Conjugate Gradient solverPreconditioned Conjugate Gradient solver
•• Parallel resolution by mesh partitioningParallel resolution by mesh partitioning
•• Updated Lagrangian formulationUpdated Lagrangian formulationwith automatic with automatic remeshingremeshing (topological, MTC)(topological, MTC)
v,b p
P1+/P1
Velocity Pressure
tVXX tttt Δ+=Δ+
Finite Element discretisation & FORGE3® solveur
( ) 0PVR ttt =,
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
Modeling and experimental Modeling and experimental resultsresults
Plunging phasePlunging phase
Plunge experimentPlunge experimentThermocouples Thermocouples
•• Weld MaterialWeld Material——12.7 mm to 20.6 mm radius,12.7 mm to 20.6 mm radius,at a depth of 1.6 mmat a depth of 1.6 mm
•• FSW ToolFSW Tool——1.2 mm of depth1.2 mm of depth
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
•• 6 Second Plunge6 Second Plunge1.19 mm/s plunge speed, 600 RPM1.19 mm/s plunge speed, 600 RPM
•• Lagrangian sensors were placed in Lagrangian sensors were placed in the FSW weld material (1.6 mm)the FSW weld material (1.6 mm)
•• RemeshRemesh every 4 time stepsevery 4 time steps•• Adiabatic contact heat transfer Adiabatic contact heat transfer
condition, Convective cooling on condition, Convective cooling on free surfacesfree surfaces
FFORGEORGE33®® simulationsimulation1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
Comparison :Comparison :experimental / numerical resultsexperimental / numerical results
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
Numerically Determined Temperatures at Six Thermocouple Locations of the FSW Plunge model in Forge3.
0.00
50.00
100.00
150.00
200.00
250.00
300.00
350.00
400.00
450.00
500.00
0.00 1.00 2.00 3.00 4.00 5.00 6.00
Tim e (seconds)
Tem
pera
ture
(deg
C) 12.7 mm
14.3 mm
15.9 mm
17.5 mm
19.1 mm
20.6 mm
Experimental Temperatures at Six Thermocouple Locations1.19 mm/s plunge speed--600 RPM
0
50
100
150
200
250
300
350
400
450
500
0.00 2.59 5.18 7.78 10.37 12.96
Time(seconds)
Tem
pera
ture
(deg
C)
-8.00
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00
1.00
2.00
Z po
sitio
n (m
m)
12.7 mm
14.3 mm
15.9 mm
17.5 mm
19.1 mm
20.6 mm
Tool Z Pos ition
Workpiece Temperature RiseWorkpiece Temperature Rise
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
A Comparison of the Experimental and Forge3 Temperatures at 12.7 mm (6.35 mm Pin Length)
0
50
100
150
200
250
300
350
400
450
500
0 1 2 3 4 5 6 7
Tool Position into the Weld Material (mm)
Tem
pera
ture
(deg
C)
Experimental Temp 12.7 mmForge3 Temp 12.7 mm
•• Weld Material Temperature ProfilesWeld Material Temperature Profiles
Workpiece Temperature RiseWorkpiece Temperature Rise
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
Tem peratures at Three Tool Locations1.19 m m /s plunge speed--600 RPM
0
100
200
300
400
500
600
0.00 2.59 5.18 7.78 10.37 12.96
Time (seconds)
Tem
pera
ture
(deg
C)
-0.30
-0.20
-0.10
0.00
0.10
0.20
0.30
Z po
sitio
n (in
ches
)
Shoulder Tem p
Root Tem p
Tip of Pin Tem p
Z Pos ition
•• Tool Temperature and Workpiece IsothermsTool Temperature and Workpiece Isotherms
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
Geometric data :Geometric data :partpart : 127mm x 127mm x 19mm: 127mm x 127mm x 19mmexperimental welding toolexperimental welding tool (concave shoulder, 3(concave shoulder, 3°° tilted) : tilted) :
pin : pin : ∅∅==8mm , h= 7mm8mm , h= 7mmshoulder : shoulder : ∅∅==25.4mm, h=90mm25.4mm, h=90mm(cooling (cooling 1010°°C forced on 60mm from the top surface)C forced on 60mm from the top surface)
rotational speed : 15 rotation/secondrotational speed : 15 rotation/secondadvance speed : 5 mm/secondadvance speed : 5 mm/second
Thermal and mechanical data :Thermal and mechanical data :Convective exchange with air on all surfaces (Convective exchange with air on all surfaces (hhcrcr=30 W/m=30 W/m²²))Same standard behavior law for Same standard behavior law for aluminumaluminumNorton Norton viscoplasticviscoplastic law : law : coefficient αf from 0.6 at 0°C to 1.1 at 650°C (linear evolution)
q from 1 at 0°C to 0.5 at 650°C (linear evolution)
Density, conductivity, and heat capacity in paperDensity, conductivity, and heat capacity in paper
Welding phaseWelding phase
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
6s simulation with an arbitrary initial temperature6s simulation with an arbitrary initial temperature
Pure Eulerian Simulation : neglect of free Pure Eulerian Simulation : neglect of free surfaces movement / no surfaces movement / no remeshingremeshing
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
6s simulation with an arbitrary initial 6s simulation with an arbitrary initial temperature fieldtemperature field
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
Thermal and mechanical data :Thermal and mechanical data :Adiabatic rigid tool Adiabatic rigid tool heat due to friction and plastic deformation onlyheat due to friction and plastic deformation onlyStandard behavior law for Standard behavior law for aluminum in hot forming process (Hansel aluminum in hot forming process (Hansel SpitelSpitellaw) :law) :
““StrongStrong”” friction (Coulomb law) : friction (Coulomb law) :
εεεσ0011.0
09964.001383.00.0479T−
−−= eAef&
⎪⎪⎩
⎪⎪⎨
⎧
>=
<=
),(),(
),(
6.03.0ΔvΔv6.0
3.0ΔvΔv3.0
εε
ε
στ
σστ
TnT
Tnn
KifK
Kif
Geometric data :Geometric data :partpart : 60mm x 60mm x 20mm: 60mm x 60mm x 20mmsimplified welding toolsimplified welding tool (no concave shoulder, 3(no concave shoulder, 3°° tilted) : tilted) :
pin : pin : ∅∅==6mm , h= 6mm6mm , h= 6mmshoulder : shoulder : ∅∅==20mm, h=60mm20mm, h=60mmrotational speed : 15 rotation/secondrotational speed : 15 rotation/secondadvance speed : 1 mm/second advance speed : 1 mm/second
Lagrangian capabilities : simulation of a Lagrangian capabilities : simulation of a defect during defect during ““cold weldingcold welding””
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
6s simulation with a low low initial temperature6s simulation with a low low initial temperature
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
e1
e2
e1
e2
t1t2
Eulerian mesh
e1
e2
e1
e2
t1 t2
Lagrangian mesh
e1
e2
e1
e2
t1 t2
ALE mesh
ALE formulationALE formulation
Different Descriptions :Different Descriptions :1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
⎪⎩
⎪⎨
⎧
−=
∇+=
wvc
c. ϕϕϕ
dtd
dtd g v : material velocity
w : mesh velocity
Splitting Method ( used firstly )= lagrangian iteration + transport on the new mesh
Convective Approach (upwind aspect )
∫+=+
Δt
gtref
ΔttALE dt
d ϕϕϕ
The two main steps of the ALE The two main steps of the ALE description implemented in description implemented in ThercastThercast ::
Convective terms treatment Convective terms treatment 1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps → Mesh velocity computation : w
Velocity Centering Method
ALE
No Updated Lagrangian Mesh construction
Geometric data :Geometric data :partpart : 127mm x 127mm x 19mm: 127mm x 127mm x 19mmsimplified toolsimplified tool (no concave shoulder, not tilted) : (no concave shoulder, not tilted) :
pin : pin : ∅∅==8mm , h= 7mm8mm , h= 7mmshoulder : shoulder : ∅∅==25.4mm, h=90mm25.4mm, h=90mm(cooling (cooling 1010°°C forced on 60mm from the top surface)C forced on 60mm from the top surface)
rotational speed : 15 rotation/secondrotational speed : 15 rotation/secondno advance speedno advance speed
Thermal and mechanical data :Thermal and mechanical data :ExangeExange with bottom plate model by a coefficient with bottom plate model by a coefficient hhcrcr=300 W/m=300 W/m²² and and exchange with air on other surfaces (exchange with air on other surfaces (hhcrcr=30 W/m=30 W/m²²))Same standard behavior law for Same standard behavior law for aluminumaluminumNorton Norton viscoplasticviscoplastic law law Density, conductivity, and heat capacity depend on temperatureDensity, conductivity, and heat capacity depend on temperature
Temperature map and velocity vectors after 15s
ALE simulation of the dwelling phaseALE simulation of the dwelling phase
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
•• 15s simulation without any 15s simulation without any remeshingremeshingstability of ALE formulationstability of ALE formulation
(Initial temperature obtained after plunging phase)(Initial temperature obtained after plunging phase)
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
150
170
190
210
230
250
270
290
310
330
350
0 2 4 6 8 10 12 14 16
time (s)
tem
pera
ture
(°C
)
2 experimental
6 experimental
6 numerical
2 numericalNorton Friction
T (°C) 0 650α 1 2q 1 0.5
Norton FrictionT (°C) 0 650α 0.6 1.1q 0 0.5
Tresca Friction=0.5Tresca Friction
=0.6
ComparisonComparison withwith experimentalexperimental resultsresults
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
III. Modeling andIII. Modeling andexperimental resultsexperimental results
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
SummarySummary
• Lagrangian, Eulerian, and ALE approaches have been used to simulate FSW, using Forge3® and Thercast®
• The ALE approach is best adapted for modeling this process, because it takes into account changes in the free surface while avoiding element degeneration in high deformation zones
• Implementation of a complete ALE formulation in Forge3® code
• Test of different transport techniques : - nodal upwind- SUPG- MLS / RBF
with use of adaptive remeshing to minimize transport diffusion
• Further comparison between experiment and simulation
• Experimental work to study friction, material behavior, and heat transfer coefficients
Future WorkFuture Work
1. The process1. The process
I. BackgroundI. Background
2. Modeling of FSW 2. Modeling of FSW
II. Numerical models II. Numerical models FFORGEORGE33®® & T& THERCASTHERCAST®®
3. ALE formulation3. ALE formulation
1. Plunging phase1. Plunging phase
2. Welding phase2. Welding phase
Future WorkFuture Work
Plunge experimentPlunge experimentFFORGE3ORGE3®® simulationsimulationComparisonComparison
Eulerian SimulationEulerian SimulationLagrangian SimulationLagrangian Simulation
Different descriptionsDifferent descriptions
Dwelling phaseDwelling phaseThe two main stepsThe two main steps
III. Modeling andIII. Modeling andexperimental resultsexperimental results