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Heat treatment simulation

DynaWeld®

Preprocessor for welding and heat treatment with LS-DYNA

followed by welding structure simulation

Welding structure simulation

09.02.2018 Consulting for welding and heat treatment simulation

DynaWeld GmbH & Co. KGSüd: Herdweg 13, D-75045 WössingenNord: Hermann-Löns-Straße 3A, D-21382 BrietlingenKamen: Herbert-Wehner-Straße 2, D-59174 KamenE-Post: info@dynaweld.de Web: www.dynaweld.eu

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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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• 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

JMatProWeldWareUser data

Welding- or heat treatment specific

parameter

Material specification

LS-DYNAmulti phase material

*MAT_254

LS-DYNAother material models

*MAT_nnn

LS-DYNAsingle phase material

*MAT_270

DynaWeldMaterial

Phase extensionFlow curve adjustment:

Base MaterialInitial strain

Crack Risk criterionDammage criterion

HardenessID 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.