1 Dr.-Ing. Tobias Loose Ingenieurbüro Tobias Loose, Herdweg 13, D- 75045 Wössingen [email protected] www.tl-ing.eu Introduction in Welding and Heat Treatment Simulation Application Fields and Benefits Workshop Welding and Heat Treatment with LS-DYNA on the 10. European LS-DYNA Conference 2015 Würzburg Foto: ISF Herdweg 13, D-75045 Wössingen Lkr. Karlsruhe E-Post: [email protected]Web: ww.tl-ing.eu, www.loose.at Mobil: +49 (0) 176 6126 8671 Tel: +49 (0) 7203 329 023 Fax: +49 (0) 7203 329 025
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Introduction in Welding and Heat Treatment Simulation … · Introduction in Welding and Heat Treatment Simulation Application Fields and Benefits Workshop Welding and Heat Treatment
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right: Animation of thermal strain and transformation strain during the heating an colling at different cooling rates (S355)bottom right:Transformation and Dilatation (1.4317)bottom left: Phase-Cooling-Rate -Diagram S500 comparison of given data and simulaion
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Process Types
• Fusion Welding – Arc– Arc Welding
– Gas Metal Arc Welding
– Submerged Arc Welding
– Tungsten Inert Gas Welding
• Electro-Resistand Welding– Spot Welding
• Friction Welding– Rotational Friction Welding
– Orbital Friction Welding
– Friction Stir Welding
• Fusion Welding – Beam– Laser Welding
– Electron Beam Welding
Welding Structure Analysis with
Equivalent Heat Source
Special Analysisfor Welding Process
EM, FEM, EFG, SPH
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Equivalent Heat Source
• The Equivalent Heat Source is a coupled function of geometry and intension of the heat generation density.
• It describes the thermal loading of a welding structure simulation.• Its aproach is to generate the same heat input as the real proccess.• It is an engineering aproach and not real physics.• It covers fluid dynamic effects like convection in the weld pool.• Any funktion is allowed.• SimWeld can predict the heat source parameter for GMAW.
Foto: ISF
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Validation
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• Plate with the dimension270 x 200 x 30 mm3 with V/U-shaped groove
Temperature – Equivalent StressLateral Residual Stress - Longitudinal Residual Stress
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Validation Nitschke-Pagel Test
Distortion w:Experiment: 0,34 mmSysweld: 0,32 mmLS-DYNA: 0,34 mm
Loose, T.: Einfluß des transienten Schweißvorganges auf Verzug, Eigenspannungen und Stabiltiätsverhalten axial gedrückter Kreiszylinderschalenaus Stahl, Diss, Karlsruhe, 2008
Quenching of a Gear made of S355Temperature – 20 times scaled displacement
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Quenching of a Gear made of S355Martensit - 20 times scaled displacement
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Quenching of a Gear made of S355Temperature – Surface and mid-cross-section
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Quenching of a Gear made of S355Temperature Curve
EdgeMiddle
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Martensit (right)
Hardness HV (bottom left)
Yield (bottom right)
Quenching of a Gear made of S355Results of Heat Treatment Simulation
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Process ChainFormingWeldingHeat Treatment
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Simulation of the Process Chain
MaterialSimulation
Process Simulation
Structure Simulation
Welding & HTSimulation
Forming
CrashClamping and Predeformation
Cutting andGrinding
Assembly
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Deep-Drawing of a Cup from a Laser Welded SheetTask and Model
Welding:• Two sheets (S355) with 1 mm wall thickness are laser weldedForming:• The welded and distorted sheet is
clamped• a globular die is pressed slow in the
sheet.
Model:• Shell-elements are used for the sheet, solid elements are used for the clamps and the die• Same material model (*MAT_244) is used in all steps• History variables, phase proportions and deformations are kept from one step to an other• Welding: implicit analysis, Forming / Crash: explicit analysis
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Stresses and Strains in Midsurface of Shell
After welding and coolingtop left: Longitudinal stresstop right: Effectiv stress (v. Mises)bottom right: plastic strain
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Microstructure
After welding and coolingtop left: Ferrit proportiontop right: Bainit proportionbottom right: Martensit proportion
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Deep drawing – effectiv stress
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Stresses and Strains in Midsurface of Shell
top left: effectiv stress bevor unclamping 200 .. 1100 N/mm²
bottom left: effectiv stess after unclamping 0 .. 200 N/mm²
bottom right: plastic strain after unclamping 0 .. 0.65 m/m
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Microstructure during Deep-Drawing
top left: Ferrit proportiontop right: Bainit proportionbottom right: Martensit proportion
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Thinning of the SheetInfluence of Material Property Change from Welding
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Manufacturing of a BoxTask and Model
Forming:• The roof geometry is made by forming a 3 mm thick sheet (1.4301)Assembly:• Add the sidewallWelding:• Weld the sidewall to the roofClamp and predeformation:• press the sidewall on measureAssembly:• Add the bottom plateWelding:• Weld the bottom plate to the sidewallUnclampingModel:• Solid-element model• Material model (*MAT_270) is used in all steps• History variables and deformations are kept from one step to an other• Implicit analysis in all steps
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Benefit of a Continous Simulation of Process Chain
• Precalcualtion of the final state of the assembly:– geometry
– residual stresses
– microstructure
• Complete simulation of the entire manufacturing process• Take into account the two way impact of single manufacturing tasks
• Enables the design of the manufacturing process• Enables the desing of compensation methods for requested conditions