DynaWeld. Preprocessor for welding and heat treatment with LS-DYNA. Heat treatment simulation. Welding structure simulation

Transcription

1 DynaWeld GmbH & Co. KG Süd: Herdweg 13, D Wössingen Nord: Hermann-Löns-Straße 3A, D Brietlingen Kamen: Herbert-Wehner-Straße 2, D Kamen E-Post: Web: DynaWeld Preprocessor for welding and heat treatment with LS-DYNA Heat treatment simulation Welding structure simulation followed by welding structure simulation

2 Preprocessor DynaWeld Environment Preprocessor for welding and Heat Treatment Analyse-Controller 2

3 Model Setup with DynaWeld Material Management DynaWeld enables the setup of preheating, welding, heat treatment, grinding and structural loading in one simulation model... Welding process Forming tools Pre- / postheating Clamps Loads Grinding Generate solver code with autodedect of all processes and run simulation Heat treatment process Quenching media or in multiple stage simulations with initial conditions of prior step. 3

4 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 4

5 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. 5

6 Preprocessor Overview 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 6

7 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. 7

8 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 8

9 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 for multilayered welding 9

10 Input of Heat Treatment Parameter User defined or auto detected quenching surface Considers diving into liquid quenching media by diving vector or by two nodes Process Start Times automatic or userdefined timestepping Furnance heating by real simulation with heat convection or by temperature curve 10

11 Operation Concept DynaWeld Process Plan Boundary Conditions and Loads: F,u Time control Load / displacement-control t Symmetry Boundary condition Movement Force Pressure Temperature Voltage Current Tools and clamps driven by force driven by displacement 11

12 Preprocessor Additional Features 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 12

13 Materials and Models 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) Source: Bernd Hochholdinger, DYNAmore Swiss 13

14 Materials and Models Material Data multi-phase single-phase Interfaces 14

15 DynaWeld Material source: Material specification Crack Risk criterion Damage criterion Hardness ID Management LS-DYNA single phase material *MAT_270 JMatPro EDA ICME WeldWare User data DynaWeld Material LS-DYNA multi phase material *MAT_254 Welding- or heat treatment specific parameter Phase extension Flow curve adjustment: Base Material Initial strain LS-DYNA other material models *MAT_nnn 15

16 DynaWeld Flow-Curve Adjustment Methode according Loose [*] strue strue, hardening eplrm = plastic strain at ultimate stress basic curve Rm Rm-Re adjusted curve Re Rm of adjusted curve Re of adjusted curve etrue,plastic eplrm The DynaWeld flow curve adjustment takes into account Re and Rm as well as different ratio Re / Rm between basic curve and adjustet curve Adjustment factor Yield (Re): Re-adjust / Re-basic Adjustment factor Hardening (Rm - Re): (Rm-adjust - Re-adjust) / (Rm-basic - Re-basic) etrue [*] Loose, T.: Einfluß des transienten Schweißvorganges auf Verzug, Eigenspannungen und Stabiltiätsverhalten axial gedrückter Kreiszylinderschalen aus Stahl, Karlsruhe, Diss

17 Materials and Models Material Data Curve display for each material parameter 17

18 Process Chain Process Chain enabled by one-code-strategy (Example) Forming Heat Treatment Welding Crash Analysis 18

19 Resistance Spot Welding Resistance Spot Welding - Process Simulation Method for process parameter dependend estimation 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 resistance pressure and time dependend Adaptive joining of components within the nugget by local welding contact Cooling of electrodes 19

20 Resistance Spot Welding Resistance Spot Welding Structure Simulation Method for the structural distortion evaluation of multiple weld spots in series Approaching Heat input by equivalent heat sources Compression 3 Fully thermal-mechanical coupling Load-time-regulation of the electrodes Adaptive joining of components within the nugget by local welding contact Welding Cooling of electrodes 4 Release 5 Cooling 20

21 Overview Welding Structure Analysis Welding Processes 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 mm Single Steps Clamping Predeformation Heating Cooling Re-Heating Tempering Unclamping Grinding Rewelding Achievable Results: Distortion, residual stress, local change of material properties, clamp concept 21

22 Welding and Heat Treatment 22

23 Overview Heat Treatment Heat Treatment Processes Quenching Case Hardening (under development) Single Steps Heating Thermal or Inductive Carburization (under development) Cooling Inductive Hardening (under development) Quenching Reheating Tempering Press Hardening Achievable Results: Properties by local change of material and microstructure, distortion, residual stress 23

24 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 2016 High Performance Computing Center, Stuttgart 24

25 High Performance Computing Shell-model Elemente, Elements, mechanical analysis, Schalenmodell mechanische Analyse, explizitexplicit Schalenmodell mechanische Analyse, explizitexplicit Shell-model Elemente, Elements, mechanical analysis, PRACE/SHAPE Project HPC Welding: good performance implicit analysis good scaling at high number of cores, explicit analysis 25

26 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. 26