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SheetSheet Metal Metal FormingForming IIII
Prof. Dr.-Ing. F. Klocke
Simulation Techniques in Manufacturing
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Sheet Metal Forming - Contents
� Modeling
� Reasons for modeling
� Connection: process modelling - process chain
� Simulation of Sheet Metal forming
� Commercial FE codes for sheet metal forming
� Case Study
� Part Evaluation: Step by step
� Process optimisation by improved tool design
� Evaluation of wrinkling
� Economical aspects of process modelling
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Why process modelling?
Car Body
Time Cost
Quality
Increase quality
Apply new materials(Al, Mg, …)
Use material moreefficiently
Reduction of toolcost
Reduction of leadtime
Reduction of timerequired for training
Increase reliabilityof production
Manufacture complex parts
Reduction of pre production trials
Source: BMW
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Integration of process modelling into the process chain
Source: BMW
Designof car
exterior
Part design
Partproduction
Means of production Tool manu-facturingand testingTool designPlanning
Sheet metal forming simulation
Part evaluation Process optimisation
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Methods applied:- 2D modelling- one-step modelling- modelling with membrane elementsShort computation time with sufficientprecision
Methods applied:- Simulation with membrane elements- Simulation with shell elements
High Precision within acceptablecomputation times
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Sheet Metal Forming II - Contents
� Modeling
� Reasons for modeling
� Connection: process modelling - process chain
� Simulation of Sheet Metal forming
� Commercial FE codes for sheet metal forming
� Case Study
� Part Evaluation: Step by step
� Process optimisation by improved tool design
� Evaluation of wrinkling
� Economical aspects of process modelling
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Commercial FE codes for sheet metal forming
2D Modelling of selected cross sections:• Abaqus www.abaqus.com
• Ansys www.ansys.com
• Autoform 2D www.autoform.ch
• Deform 2D www.deform.com
• Marc www.marc.com
•...
Advantages:
• reduced computation time
• less sensitive to quality of input
data
• usually less input data required
Disadvantages:
• difficult selection of cross sections
to be modelled
• less accurate results
Source: BMW / Fontana Pietro SPA
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One-step simulation:
• Isopunch
• SIMEX
• Corps
• AutoForm Onestep
• ...
Advantages:
• reduced computation time
• usually less input data required
• suitable tool for part evaluation
Disadvantages:
• decreasing significance due to
increasing computing power
• still not very accurate
Source: BMW
Commercial FE codes for sheet metal forming
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Model with membrane elements:
• AutoForm Incremental
• Abaqus
• ...
Advantages:
• acceptable computation time
• suitable tool for part evaluation
• suitable for process optimisation
• basically accurate results
Disadvantages:
• long computation time
• problems when severe bending
occurs
• not accurate enough in predicting
wrinkles
• requires high quality input dataSource: BMW
Commercial FE codes for sheet metal forming
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Model with shell elements:
• PAM-STAMP
• Optris
• DYNA-Form
• Indeed
• ...
Advantages:
• state of the art tools for process
optimisation
• very accurate results
Disadvantages:
• long computation time leads to
long response time
• requires high quality input data
Source: BMW
Commercial FE codes for sheet metal forming
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Sheet Metal Forming II - Contents
� Modeling
� Reasons for modeling
� Connection: process modelling - process chain
� Simulation of Sheet Metal forming
� Commercial FE codes for sheet metal forming
� Case Study
� Part Evaluation: Step by step
� Process optimisation by improved tool design
� Evaluation of wrinkling
� Economical aspects of process modelling
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Part Evaluation: One step method
Steps:
1) Create mesh from 3D
CAD model
2) create blank holder
3) simplified add-on
4) computation
5) interpretation of results
Source: BMW
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Part Evaluation: One step method
Source: BMW
Steps:
1) Create mesh from 3D
CAD model
2) create blank holder
3) simplified add-on
4) computation
5) interpretation of results
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Source: BMW
Steps:
1) Create mesh from 3D
CAD model
2) create blank holder
3) simplified add-on
4) computation
5) interpretation of results
Part Evaluation: One step method
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Source: BMW
Steps:
1) Create mesh from 3D
CAD model
2) create blank holder
3) simplified add-on
4) computation
5) interpretation of results
Part Evaluation: One step method
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Source: BMW
Steps:
1) Create mesh from 3D
CAD model
2) create blank holder
3) simplified add-on
4) computation
5) interpretation of results
Part Evaluation: One step method
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Source: BMW
Steps:
1) Create mesh from 3D
CAD model
2) create blank holder
3) simplified add-on
4) computation
5) interpretation of results
Part Evaluation: One step method
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Sheet Metal Forming II - Contents
� Modeling
� Reasons for modeling
� Connection: process modelling - process chain
� Simulation of Sheet Metal forming
� Commercial FE codes for sheet metal forming
� Case Study
� Part Evaluation: Step by step
� Process optimisation by improved tool design
� Evaluation of wrinkling
� Economical aspects of process modelling
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Case study: Process optimisation by improved tool design
Source: BMW
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Process optimisation: Tool design
Source: BMW
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Process optimisation: Tool design
Source: BMW
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Process optimisation: Tool design
Source: BMW
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Process optimisation: Material data
Source: BMW
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Process optimisation: Process parameters
Source: BMW
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Process optimisation: Numerical parameters
Source: BMW
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Process optimisation: Forming process
CAD-datatool
& blank
Meshing
Process dataNumerical
data
GENERIS
Material-data
PAM-STAMP Input fileSource: BMW
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Process optimisation: Forming sequence
Source: BMW
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Process optimisation: Forming sequence
Source: BMW
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Source: BMW
Process optimisation: Forming sequence
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Source: BMW
Process optimisation: Forming sequence
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Source: BMW
Process optimisation: Forming sequence
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Source: BMW
Process optimisation: Forming sequence
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Source: BMW
Process optimisation: Forming sequence
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Sheet Metal Forming II - Contents
� Modeling
� Reasons for modeling
� Connection: process modelling - process chain
� Simulation of Sheet Metal forming
� Commercial FE codes for sheet metal forming
� Case Study
� Part Evaluation: Step by step
� Process optimisation by improved tool design
� Evaluation of wrinkling
� Economical aspects of process modelling
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Case study: Evaluation of wrinkling
distribution of effective strain during and after the drawing process
Source: BMW
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Process optimisation: Evaluation of wrinkling
Source: BMW
distribution of effective stress during and after the drawing process
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Process optimisation: Comparision between simulation and real part
Source: BMW
wrinkling
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Process optimisation: Comparision between simulation and real part
Source: BMW
rupturing
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Sheet Metal Forming II - Contents
� Modeling
� Reasons for modeling
� Connection: process modelling - process chain
� Simulation of Sheet Metal forming
� Commercial FE codes for sheet metal forming
� Case Study
� Part Evaluation: Step by step
� Process optimisation by improved tool design
� Evaluation of wrinkling
� Economical aspects of process modelling
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Modelling sheet metal forming: Quality of the computed results
0+springback
++++wrinkles
+++rupture
Quality
qualitatively quantitatively
Result
Source: BMW
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Flow chart of a modelling project
Partgeometry
no
yes
Part design Process development Simulation all
Materialselection
tools(CAD)
Processparameters
Simulation Start tooldesign
Source: BMW
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Effort for a sheet metal modelling project
Change of responsible effort CAD effort Simulation
Process parameters
(friction, beads, ...)Process design ---- 1h --3h
die setup (blank holder,
etc. ...)Process design 1d -- 1w 3h -- 1d
Material quality and
thicknessBody design ---- 1h -- 3h
Part geometry Body design 1d --1w 3h -- 1d
Total effort for a medium sized part: Usually 2 weeks
Source: BMW
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Preprocessing effort for a modelling project in sheet metal forming
1993 2000
1W
2 W
3 W
Effort for preprocessingSource: BMW
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Development of computing power and computation time
100%
1993 2000
20%
Increase of computing power
1993 2000
50h
15h
Reduction of computationtime for a large car body
partSource: BMW
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Development of hardware cost
1993
Hardware cost
2000
100 %
< 1 %
Source: BMW
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Prerequisits for the industrial application of process modelling
Time: Cost: Quality:
Short responsetimes
Low projectcost
Reliable results
Integration into the process chain of a car body
Source: BMW
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Simulation of crashworthiness for the Ford Explorer (LS-Dyna)
Source: Livermore Software Technology