lightweight forming technologies - iom3 · lightweight forming technologies 15/10/2014 prof....
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Lightweight Forming TechnologiesLightweight Forming TechnologiesLightweight Forming TechnologiesLightweight Forming Technologies
15/10/2014
Prof. Jianguo Lin and Dr. Mohamed Mohamed
Metal forming and Materials Modelling Group
Research – Automotive related activities
Forming Processes: e.g., Forging, Extrusion, sheet metalforming – springback and formability, joining – riveting andwelding; Hot stamping and cold-die quenching for steel andaluminium alloys; Creep Age Forming (CAF).
Testing facilities: Gleeble 3800, a range of hydraulic pressesfor forging and sheet metal forming.
The Group has 30 researchers (Post-Doc RAs and PhDs)
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1. LoCoLite project – Status: very good progress
2. LCV-TARF project-Status: very good progress
2. UlCab project has been run for 1 year and good results obtained
3. A new TSB project "LightBlank" will start next year (confirmed), 6 UK partners and Total: £1.5m.
4. Other research project related to: Hot stamping with TATA Steel; Lightweight forming for China aerospace company; etc.
Current Projects
Solution Heat treatment, cold die Forming Solution Heat treatment, cold die Forming Solution Heat treatment, cold die Forming Solution Heat treatment, cold die Forming
and Quenching (HFQ) for automotive and and Quenching (HFQ) for automotive and and Quenching (HFQ) for automotive and and Quenching (HFQ) for automotive and
aerospace applications aerospace applications aerospace applications aerospace applications
This is a patented solution for forming high strength, complex-shaped lightweight panel parts
The HFQ process is Licenced by Impression Technologies LTD (ITL)
Patented for 53 Countries in the world
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� Enable cost-effective lightweight components to be
realised.
HFQ process
� This can be done by form complex components from
high-strength sheet aluminium and Magnesium
Essential requirements
- Standardise the Material Testing Procedures
- Developing a full calibrated Material Modelling
(accurate failure prediction)
Current State of Art
Lightweight Body and Chassis Structures for
passenger cars
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The patented solution for forming high strength,
complex-shaped lightweight panel parts
Solution-Heat treatment, cold-die
Forming & Quenching (HFQ)
A range of testing facilities developed for HFQ
Presses: Capacity range: 2500KN to 20kN; Speed range: 0-25 m/s. For forming and impact testing
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FLDFLD
Q2-Is the Conventional FLD a
suitable tool to predict failure?
Q1- How to predict the
Failure accurately?
Why FLD is not a proper failure criteria to predict
Failure at elevated temperature?
(a) Temperature field
(b) Strain filed
temperature and strain rate usually vary
dynamically and spatially in a sheet work-piece
during the hot stamping
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( )/ 1n
ep
e
R k
K
σ ωε
− − −=
&
3
2
i jp p
i j e
e
Sε ε
σ= &
.. 0 5R 0 5Bρ ρ−=& &
( ) 2np
eA 1 Cρ ρ ε ρ= − −& &
( ) ( ) 1 p
ij ijkl ij ijDσ ω ε ε= − −
( ) ( )( ) 3
2
p1 1 2 H 3 e 1 e
e
e1 2 3
3.
1
ϕη
ϕ η
α σ α σ α σ η σω ε
σα α α ω
+ +∆=
+ + −& &
11 11,ε σ
22 22,ε σ
33ε
1
2
3
New Continuum damage model (CDM) for
formability prediction
(1)
(2)
(4)
(3)
(5)
(6)
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CDM model Calibration using Experimental FLD for AA5754 different temperatures and strain rates
75
mm/sec 250°°°
°C
Calibration of CDM Model for AA6082 at Room
Temperature
0
50
100
150
200
250
300
350
400
450
0 0.1 0.2
Str
ess
(M
Pa
)
Strain
AA6082-20°C
-0.2
0
0.2
0.4
0.6
0.8
0 0.1 0.2
Da
ma
ge
Strain
AA6082-20C
0
0.2
0.4
0.6
0.8
1
1.2
1.4
-0.7 -0.2 0.3 0.8 1.3
Majo
r str
ain
Minor strain
EXP: 20°C
500°C
400°C
350°C
20°C
Prediction of FLC for AA6082 at different temperature
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170
17
0
Φd
4x Φ5.5on
150 PCD
ΦD(punch)
Formability
tester design
Model Validation : Formability investigation using new test design for
hot stamping process
Fo
rma
bil
ity
Sa
mp
le d
esig
n
failure features of deformed cup with the different
diameter ratio
Test Mode 1
(Circumference failure)
Test Mode 2
(Central Hole failure)
Test Mode 3
(Punch goes through the
sample without tearing)
Diameter ratio (ϒ =d/D): 0.0 0.025 0.05 0.1 0.15 0.2 0.225 0.25
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Applications of CDM model: B-pillar-Lotus
FLD
0.7
0.58
0.43
0.35
0.23
0.19
0.0
Damage
0.023
0.021
0.018
0.016
0.014
0.0
HFQ
Applications of CDM model: Lotus Bulkhead part
Die
Binder
Punch
(Fixed)
Movement of
Die
Blank Holding
pressure
Blank
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Cold Forming
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 0.1 0.2 0.3 0.4 0.5
Da
ma
ge
Time (sec)
Damage
A
A
B
B
A-A
B-B
FLD CDM
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0 0.05 0.1 0.15 0.2 0.25 0.3
Da
ma
ge
Time (sec)
HFQ
11
0.4
0.6
0.8
1
1.2
1.4
1.6
0 50 100 150 200 250 300 350 400
No
rma
ize
d t
hic
kn
ess
(t/
to)
Distance through the section (mm)
X
A
A
B
B
Symbols: Experimental measurementsSolid Lines: Computational measurements
Thickness Distribution
0.4
0.6
0.8
1
1.2
1.4
0 100 200 300 400 500
Nor
mai
zed
Thic
knes
s (t/
t0)
Distance through the section (mm)
X
0.4
0.6
0.8
1
1.2
1.4
1.6
0 50 100 150 200 250 300 350 400
No
rm
aiz
ed
th
ick
ne
ss (
t/to
)
Distance through the section (mm)
X
Thickening due to wrinkling