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Simulation Techniques in Manufacturing

Lecture no. 7

„„Sheet Metal Forming IISheet Metal Forming II““

Prof. Dr.-Ing. F. Klocke

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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

Sheet Metal Forming - Contents

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Why process modelling?

Car BodyTime 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 simulationPart evaluation Process optimisation

So

ftw

are

so

luti

on

Ap

pli

ca

tio

nP

roce

ss c

ha

in

Methods applied:- 2D modelling- one-step modelling- modelling with membrane elementsShort computation time with sufficient precision

Methods applied:- Simulation with membrane elements- Simulation with shell elements

High Precision within acceptable computation times

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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

Sheet Metal Forming II - Contents

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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 inputdata

• usually less input data required

Disadvantages:

• difficult selection of cross sectionsto be modelled

• less accurate results

Source: BMW / Fontana Pietro SPA

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Commercial FE codes for sheet metal forming

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

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Commercial FE codes for sheet metal forming

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 bendingoccurs

• not accurate enough in predicting wrinkles

• requires high quality input dataSource: BMW

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Commercial FE codes for sheet metal forming

Model with shell elements:

• PAM-STAMP• Optris• DYNA-Form• Indeed • ...

Advantages:

• state of the art tools for processoptimisation

• very accurate results

Disadvantages:

• long computation time leads to long response time

• requires high quality input data

Source: BMW

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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

Sheet Metal Forming II - Contents

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Part Evaluation: One step method

Steps:

1) Create mesh from 3DCAD 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 3DCAD model

2) create blank holder

3) simplified add-on

4) computation

5) interpretation of results

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Part Evaluation: One step method

Source: BMW

Steps:

1) Create mesh from 3DCAD model

2) create blank holder

3) simplified add-on

4) computation

5) interpretation of results

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Part Evaluation: One step method

Source: BMW

Steps:

1) Create mesh from 3DCAD model

2) create blank holder

3) simplified add-on

4) computation

5) interpretation of results

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Part Evaluation: One step method

Source: BMW

Steps:

1) Create mesh from 3DCAD model

2) create blank holder

3) simplified add-on

4) computation

5) interpretation of results

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Part Evaluation: One step method

Source: BMW

Steps:

1) Create mesh from 3DCAD model

2) create blank holder

3) simplified add-on

4) computation

5) interpretation of results

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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

Sheet Metal Forming II - Contents

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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

Pamstamp.mov

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Process optimisation: Forming sequence

Source: 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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Process optimisation: Forming sequence

Source: BMW

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Process optimisation: Forming sequence

Source: BMW

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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

Sheet Metal Forming II - Contents

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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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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

Sheet Metal Forming II - Contents

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Modelling sheet metal forming: Quality of the computed results

0+springback

++++wrinkles

+++rupture

Qualityqualitatively 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 thickness

Body 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 computation time 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