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www.dynaweld.eu 1
Heat treatment simulation
DynaWeld®
Preprocessor for welding and heat treatment with LS-DYNA
followed by welding structure simulation
Welding structure simulation
20.07.2018
DynaWeld GmbH & Co. KGSüd: Herdweg 13, D-75045 WössingenNord: Hermann-Löns-Straße 3A, D-21382 BrietlingenKamen: Herbert-Wehner-Straße 2, D-59174 KamenE-Post: [email protected] Web: www.dynaweld.eu
www.dynaweld.eu 2
DynaWeld Preprocessor for welding and Heat Treatment
Environment Analyse-Controller
Preprocessor
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Model Setup with DynaWeld
Material Management
Welding processForming tools
Pre- / postheatingClampsLoads
Grinding
Heat treatment process
Quenching mediaGenerate solver code
with autodedect ofall processes and
run simulation
DynaWeld enables the setup of preheating, welding, heat treatment, grinding and
structural loading in one simulation model...
… or in multiple stage simulations with initial conditions of prior step.
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Supported processes and analysis features
• Welding• Resistive Spot Welding• Preheating and Post Weld Heat Treatment• Heat Treatment• Forming• Press Hardening• Grinding and Cutting
• Implicit analysis• Explicit analysis• Mass scaling, time scaling, selective mass scaling
• Restart on previous results Process chain→
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Finite Element Model
Modelling weld filler elements in new „free-motion“-filler technology:The „free-motion“-filler technology enables the best matching of true conditions in a welding structure simulation. Before welding the entire weld filler and during welding the non heated part of the weld filler is present in the simulation, even if it should not be there. Therefore the material state is set to „non active“, which means: no thermal activities, a minimum of mechanical activities. Although mechanical activities should also be zero, we need a little part of stiffness to ensure the small motions of the weld filler elements coming up due to distortions of the entire structure. Even if these stiffness part is rather small, sometimes small influences are still present. It depends on the simulation task and welding conditions, wether these influences can be neglected or should be takten into account. Possible gaps and larger relative displacements can better be detected with the „free-motion“-filler technology. Here we have an additional degree of freedom for free motion by a sliding contact interface. However, when heated up to melting point, materials are fixed permanently due to local changes of contact conditions.
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• Shell- and solid elements, hybrid models, 2D analysis
• For body in white existing models for crash or NHV can be used
• Pure thermal analysis for heat source adjustment or decoupled analysis are enabled
• With LS-DYNA solvers parallelized computation on multiple cores (HPC)
• Implicit and explicit analysis
• Many different heat source functions enable the simulation of every welding process
• Rotation and offset functions normal and transversal for heat source positioning
• Import of material data by interfaces to JmatPro, Sysweld, WeldWare
• Material models single phase or multi phase available
• User defined CCT Diagrams and material data
• Material model with crack risk criteria
• Process chain simulation enabled by one-code-strategy of LS-DYNA code
• Clamps time driven, moving or static
• Adaptive („real“) mechanical and thermal joining of welded components Welding contact→
• Resistance spot welding, electro-thermal-mechanical coupled
• Multi layered welds
Preprocessor Overview
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Operation Concept
DynaWeld is designed to manage „large“ simulation models with a large number of welds.
Thus the input of the weld plan and the related data for heat input are realized by spreadsheed tables, which can be edited in Excel or similar products. The same is for time driven clamps and other boundary conditions. The implementation in DynaWeld is by csv-files.
Thereby the management of many welds is not only faster, but the script-based automated control in DynaWeld is generally possible and is in the focus of further development.
The goal is, to minimize the human based, multiply repeated input of data within a multiple number of menues and submenues of common used GUIs and reduce the input only to necessary process parameters.
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Operation Concept – Vision of Future
DynaWeld in its future versions will go the way of digitization in the CAE-world and open the door for an efficient use in the industry.
Due to the structure of DynaWeld all data needed for the simulation can be collected automatically and brought together in one simulation model.
• Automation of derived variants
• Automatic actualization of development states
• Automation of recurring (similar) simulation tasks
• Automation of process chain
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Operation Concept
DynaWeld Process Plan Welding
Transient Welding
Metatransient Welding
Surface Heating
Reorder of weld sequence
Reverse of weld direction
Multiple heat sources on same weldline
Simultaneous welding of multiple welds Multiple welding robots
Automatic filler activation formultilayered welding
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Input of Heat Treatment Parameter
Process Start Timesautomatic or user-
defined timestepping
Considers diving into liquid quenching media
by diving vector orby two nodes
User defined or auto detected
quenching surface
Furnance heating by real simulation with
heat convection or by temperature curve
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Operation Concept
DynaWeld Process PlanBoundary Conditions and Loads:Time control
Load / displacement-control
• Symmetry
• Boundary condition
• Movement
• Force
• Pressure
• Temperature
• Voltage
• Current
Tools and clamps
• driven by force
• driven by displacement
t
F,u
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Additional Features
• Dublicate model for variations
• New process step on results
• Heat input evaluation
• Automatic calibration of heat input
• Performane analysis
• Autopostprocessing
• Launch postprocessor on scaled temperature
• Special DynaWeld post design for temperature scalar values and min-max values
Preprocessor Additional Features
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Material Models
• Simplified single-phase-model MAT_270
• takes also into account transformation strains
• initial strain (e.g from milling)
• Multi-phase-model MAT_254
• phase-kinetic-models:
• Koinstinen-Marburger
• generalized Johnson Mehl Avrami Kolmogorov
• Tempered phases
• Yield calculation of hardened sections
• Hardeness calculation
• elastic/plastic stess utilisation level
• initial strain (e.g from milling)
Materials and Models
Source: Bernd Hochholdinger, DYNAmore Swiss
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Interfaces
Material Data
Materials and Models
single-phase
multi-phase
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DynaWeld Material
source:JMatPro®
EDA® ICME WeldWare®
User data
Welding- or heat treatment specific
parameter
Material specification
LS-DYNA®
multi phase material*MAT_254
LS-DYNA®
other material models*MAT_nnn
LS-DYNA®
single phase material*MAT_270
DynaWeld®
Material
Phase extensionFlow curve adjustment:
Base MaterialInitial strain
Crack Risk criterionDamage criterion
HardnessID Management
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DynaWeld Flow-Curve AdjustmentMethode according Loose [*]
strue
etrue,plastic
Re
strue, hardening
etrue
eplRm
eplRm
= plastic strain at ultimate stress
Rm
Rm of adjusted curve
Re of adjusted curve
Rm-Re
basic curve
adjusted curve
Adjustment factor Yield (Re): Re-adjust / Re-basic Adjustment factor Hardening (Rm - Re): (Rm-adjust - Re-adjust) / (Rm-basic - Re-basic)[*] Loose, T.: Einfluß des transienten Schweißvorganges auf Verzug, Eigenspannungen und Stabiltiätsverhalten axial gedrückter Kreiszylinderschalen aus Stahl, Karlsruhe, Diss. 2007
The DynaWeld flow curve adjustment takes into accountRe and Rm as well as different ratio Re / Rm
between basic curve and adjustet curve
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Material Data
Curve display for each material parameter
Materials and Models
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Process Chain enabled by one-code-strategy
(Example)
• Forming
• Heat Treatment
• Welding
• Crash Analysis
Process Chain
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Resistance Spot Welding
- Process Simulation -
• Method for process parameter dependendestimation of single weld spots
• Dimension and development of the nugget
• Fully electro-thermal-mechaical coupling
• Load-time-regulation of the electrodes
• Time regulation of current and voltage
• Electric and thermal contact resistancepressure and time dependend
• Adaptive joining of components within the nugget by local welding contact
• Cooling of electrodes
Resistance Spot Welding
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Resistance Spot Welding
- Structure Simulation -
• Method for the structural distortion evaluation of multiple weld spots in series
• Heat input by equivalent heat sources
• Fully thermal-mechanical coupling
• Load-time-regulation of the electrodes
• Adaptive joining of components within the nugget by local welding contact
• Cooling of electrodes
Resistance Spot Welding
1
Approaching
2
Compression
3
Welding
4
Release
5
Cooling
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Welding Processes
Overview Welding Structure Analysis
Process-Type• Arc Welding• GMAW, SAW, TIG• Laser• Electron beam• GMAW/Laser-Hybrid• Resistance Welding• Resistance Spot Welding• Brazing
• Single or Multi Pass Welding• Tack Welding
Dimension:10 µm .. 500 mm
Re-HeatingTempering
GrindingRewelding
Single Steps
Achievable Results:Distortion, residual stress, local change of material properties, clamp concept
ClampingPredeformation
Heating
Cooling
Unclamping
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Welding and Heat Treatment
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Heat Treatment Processes
Overview Heat Treatment
ReheatingTempering
Single Steps
Achievable Results:Properties by local change of material and microstructure, distortion, residual stress
HeatingThermal
or Inductive
Carburization(under development)
Quenching
Inductive Hardening(under development)
Press Hardening
Quenching
Case Hardening(under development)
Cooling
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High Performance Computing
Welding Simulation on High Performance Cluster-Systems
• The LS-DYNA solvers enable significant speed-up at HPC
• Scaling also at large number of cores (more than 1000 cores explizit)
• Welding structure simulation is possible implicit as well as explicit
• Ability for cluster computation is especial for the explicit analysis a unique feature
© Copyright: HLRS 2016High Performance Computing Center, Stuttgart
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High Performance Computing
4080
Schalenmodell 200 000 Elemente, mechanische Analyse, explizit
Schalenmodell 1 000 000 Elemente, mechanische Analyse, explizit
PRACE/SHAPE Project HPC Welding:• good performance implicit analysis• good scaling at high number of cores, explicit analysis
Shell-model 200 000 Elements, mechanical analysis, explicit
Shell-model 1 000 000 Elements, mechanical analysis, explicit
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Summary
Today DynaWeld is ready for the full spectrum of welding simulations and heat treatment simulations.
The same is for the forwarding of results in following process steps (process chain).
The calculation is scaling on cluster systems, especially for explicit analysis.
The development is focussed on the real feasibility. Therefore our order of development is:
• Development of the method
• Solver adjustment
• Validation
• GUI-development for more convinience and robustness.
DynaWeld is used for engineering services.The knowledge recieved by many projects is directly integrated in the development.