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SYSWELDSYSWELDComplete Finite Element Solution for Simulation of
Welding Processes
Josef TejcMECAS ESI s.r.o. , CZ
ESI Group
Company introductionCompany introduction
Uslavska 10 , Pilsen
Czech Republic
e-mail: [email protected]
web-page: http://www.mecasesi.cz
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ESI Group’s Virtual Try-Out Space®ESI Group’s Virtual Try-Out Space®
SYSWELD 2003
SYSWELD 2003
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SYSWELD backgroundSYSWELD background
SYSWELD is a part of the SYSWORLD Finite Element program family:
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SYSWELD backgroundSYSWELD background
SYSTUS is a general purpose Finite Element product that provides most of the computation capabilities that can be handled with implicit Finite Element technology. Developed through the last 4 decades and born in the Nuclear Industry, it provides excellent non-linear computation capabilities.Most of the features developed for SYSTUS are shared through the SYSWORLD product family, i.e. it is possible to use them in SYSWELD too.
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General capabilitiesGeneral capabilities
SYSWELD 2003 simulates all physical effects that are related to:
Welding and Heat treatmentCourtesy GM
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Architecture of the codeArchitecture of the code
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Coupled thermo-metallurgical analysisCoupled thermo-metallurgical analysis
Modified heat convection equation:
( ) QATLTPtTCP
jiijij
iii
iii =⋅+
∇
∇−∂∂
∑∑∑<
λρ )(
indexes phase ... time ...
etemperatur ... proportion phase ...
jitTP
,
density mass ... ρ
sources heat ... tyconductivi thermal ...
heat specific ...
Q
Cλ
unit time in to dtransforme phase of proportion ... tiontransforma of heat latent ...
jiA
jiTL
ij
ij →)(
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Non-linear computationsNon-linear computations
SYSWELD covers 50 men years of solver developmentSYSWELD performs non-linear computations with all material properties depending on
TemperaturePhases / material transformationsProportion of chemical elementsAuxiliary variables
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Non-linear computationsNon-linear computations
SYSWELD covers all needed non-linear phenomena
Non-linear heat transfer to any extentNon-linear geometry including large strainsIsotropic and kinematic strain hardening including phase transformationsTransformation plasticityNon-linear mixture rules for the yield stress of phases
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Typical applicationsTypical applications
MIG (metal inert gas) weldingWIG / TIG weldingLaser weldingElectron beam weldingSpot weldingFriction welding
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Main results of a welding simulationMain results of a welding simulation
Temperature field and gradientPhase proportionsHardnessDistortionsResidual stressesPlastic strainsYield stress depending on the mixture of metallurgical phases
Simple Example of Welding SimulationSimple Example of Welding Simulation
Arc Welding of Steel Plate
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Part and process dataPart and process data
Plate thickness: 9mmPlate length: 120mmArc weldingWelding Speed: 5 mm/sButt weld with filler materialMade of S355_J2G3 construction steel
Formulation of the Problem and Related Input Data
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Mesh of the structureMesh of the structure
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Material propertiesMaterial properties
Thermal properties:Thermal conductivitySpecific heat / EnthalpyMass density
Usually, the properties are defined as a function of temperature and metallurgical phases
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DensityDensity
ρ [kg·mm-3]
T [°C]
Austenite
Ferrite, Bainite, Martensite
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Material propertiesMaterial properties
Metallurgical properties = phase transformation kinetics for:
Austenitic transformation during heating (TTA diagram)Transformation to Ferrite, Bainite and Martensiteduring cooling => CCT diagram
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Real CCT diagramReal CCT diagram
T [°C]
t [s]
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Models for phase transformationsModels for phase transformations
Leblond’s model
for diffusion controlled transformation
Koistinen-Marburger law
for Martensitic transformation
( )( )T
PTPTf
dtdP eq
τ−
= ..
rate olingheating/co ... etemperatur ...
time ... mequilibriu phase at proportion ...
proportion phase ...
TTt
PP
eq
&
( )T)b(MsP(T) −−−= exp1
etemperatur start-Martensite ... tcoefficienlaw ...
proportion phase ...
MsbP
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Model of the CCT diagramModel of the CCT diagram
T [°C]
t [s]
Ferrite
Bainite
Martensite
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Material propertiesMaterial properties
Mechanical properties:Young’s modulusPoisson’s ratioThermal strainYield stressStrain hardening
Usually, mechanical properties are defined as a function of temperature and phase proportions
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Yield stressYield stress
Austenite
Martensite
Ferrite
Bainite
T [°C]
σY [MPa]
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Model of heat sourceModel of heat source
Double-ellipsoid heat source
Heat transfer into the structure (t=20 s)
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Clamping conditionsClamping conditions
Symmetry conditions
Computed Thermo-metallurgical Results
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Temperature field at t=20sTemperature field at t=20s
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Temperature evolution (movie)Temperature evolution (movie)
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Austenite evolution (movie)Austenite evolution (movie)
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Bainite evolution (movie)Bainite evolution (movie)
Computed MechanicalResults
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Evolution of displacements (movie)Evolution of displacements (movie)
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Displacements UZ (with phase transf.)Displacements UZ (with phase transf.)
-0.5mm
-1.1mm
Angular distortion
z
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Displacements UZ (without phase transf.)Displacements UZ (without phase transf.)
-0.5mm
-1.1mm
Angular distortion
-1.4mm
Attention: Different scaling!z
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Stress σyy (with phase transf.)Stress σyy (with phase transf.)
Reduced tensile stress level due to phase transformations
y
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Stress σyy (without phase transf.)Stress σyy (without phase transf.)
y
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Stress σxx (with phase transf.)Stress σxx (with phase transf.)
x
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Stress σxx (without phase transf.)Stress σxx (without phase transf.)
x
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SummarySummary
The difference in computed distortions with and without phase transformations is about 30%The difference in computed stresses with and without material transformations is remarkable
Example of an Industrial Application
Example of an Industrial Application
Simulation of Welding of a T-joint Made from AlMgSi
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Courtesy ofCourtesy of
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Process movie (accelerated display)Process movie (accelerated display)
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Description of the taskDescription of the task
A rectangular hollow profile is welded with 4 joints on a thin-walled plateThe computation of distortions during and after welding is extremely sensitive due to general instability of the arrangement
The edges of the plate are freeThe plate is thin-walled and has a low resistance against bending
The welding joints influence each otherTo a certain extent, this is the worst case for simulation engineering
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Evolution of the temperature field (accelerated, scaling from 200°C to 650°C)
Evolution of the temperature field (accelerated, scaling from 200°C to 650°C)
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Displacement UZ after weld 1 (t=5.2s)Displacement UZ after weld 1 (t=5.2s)
Positive buckle at the edge parallel to WELD 1
Z
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Displacement UZ after weld 2 (t=11.3s)Displacement UZ after weld 2 (t=11.3s)
Positive buckles at the edges parallel to WELD1 and WELD2
Z
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Displacement UZ after weld 3 (t=17.4s)Displacement UZ after weld 3 (t=17.4s)
Positive buckles at the edges parallel to WELD1, WELD2 and WELD3
Z
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Displacements UZ after weld 4 (t= 22.10s)Displacements UZ after weld 4 (t= 22.10s)
Still a positive buckle at the edge parallel to WELD1.
However, the contraction of WELD4 decreases the positive buckle of WELD1 and WELD2.
Z
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Cooling from 22 to 1000 s (movie)Cooling from 22 to 1000 s (movie)
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Cooling from 22 to 1000 s (movie)Different scaling!
Cooling from 22 to 1000 s (movie)Different scaling!
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Process movie - evolution of distortions at the edge parallel to WELD 2
Process movie - evolution of distortions at the edge parallel to WELD 2
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Interpretation of resultsInterpretation of results
The computed evolution of the distortions of the edge parallel to WELD2 is nearly coincident with the displacements shown in the process movie The final displacements have been measured to around 6mmThe final displacements computed are around 6mmThe computed displacements correlate well with the experiment
Some of the New Features of
SYSWELD 2003
Some of the New Features of
SYSWELD 2003
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Interfaces PAM-STAMP/SYSWELDInterfaces PAM-STAMP/SYSWELD
In SYSWELD 2003, it is possible to read and write PAM-STAMP mapping files, in order to:
Import results from a stamping simulation in a welding simulationImport results from a welding simulation in a stamping simulation
A typical application is the stamping of welded tailored blanks
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Door panel - real imagesDoor panel - real images
fehlerfrei umgeformtes Bauteil
Courtesy of AUDI
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Interfaces PAM-STAMP/SYSWELDInterfaces PAM-STAMP/SYSWELD
Plastic strains:
Min/Max : 0/0.587
Courtesy of AUDI
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Welding Assembly simulationWelding Assembly simulation
During the last 4 years, ESI software has validated with Industrial partners a new methodology to simulate welding assembly - the local/global approach
The Welding joints are computed outside the global structure in different local models for which all physical phenomena are simulatedThen, the assembly effects in term of global distortions are computed after projection of local models results on the global structure
This methodology presents the advantage to allow the simulation of large parts supported by shell-solid models A simplified method is also available to analyse the influence of the sequence effects and the clamping tools on the distortions of assembly
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Welding Assembly simulationWelding Assembly simulation
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Material databaseMaterial databaseV2003 contains an intensively tested standard material database for Welding and Heat Treatment
heat_treatment.matwelding.mat
The standard databases will be updated continuouslyAn enhanced material database is also available
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Material databaseMaterial database
For Welding, the following materials are availableAlMgSi
Typical automotive aluminium alloyS355J2G3 (1.0570, St 52-3, Fe 510 D1, Fe 510 D1 FF,
CSN 11 523)Typical ship building steel
X20CrNi13 (1.4201, Z20C13, AISI 420, CSN 17 022)Stainless steel
X5CrNi 18 10 (1.4301, Z7CN18-09, AISI 304, CSN 17 240)
Stainless steelDC04 (St 14, St 4, AISI 1008, CSN 11 325)
Typical car body / stamping steel, deep drawing quality
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ESI Group’s solution of present daysESI Group’s solution of present days
SYSWELD:
Complete solution for realistic simulation of welding processes
Process
Product
COMPARISON WITH EXPERIMENTS:
In cooperation with industrial partners a number of experimental projects was done to proof tight agreement between results of simulation and reality.
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ESI Group’s solution of near futureESI Group’s solution of near future
Complete manufacturing chain simulation perfectly reflecting the reality
Welding / Joining
Stamping
CrashStructuralbehavior
Casting
Fatiguestrength