Next-Generation Sandwich Steel Revolutionizes
Transportation Industry
Doug Cox
President & CEO
Fabien Ebnoether
Chief Engineer
Special acknowledgements: Prof. Dirk Mohr (Ecole Polytechnique/MIT)
www.autosteel.org
Lightweight Steel
Steel industry challenge:
• Corporate Average Fuel Economy (CAFE) demanding lightweight solutions
• Growing use of aluminum - Ford announces aluminum F-150
Solution:
CellTech is a solution provider:
• Steel industry enabler
• Optimize all-steel sandwich structure for transportation applications
• Low cost sandwich manufacturing process
www.autosteel.org
Sandwich Technology│ generic
Face sheet
Lightweight
core material
Face sheet
Sandwich structure
sandwich
t
sheet
sandwich
2t
4t
Relative bending stiffness
1
7
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37
Sandwich Technology│ markets
Rail
Military
Trucks
Sports
Construction
Solar
Buses
Truck Trailer
Automotive
Marine
Furniture
Ships
Satellites
Containers
Elevators
Aerospace
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The Company│ history
• Founded in 2004 in San Diego, USA
• An engineering technology company
• Focused on light weighting metal for sandwich applications
• 2005 to 2009 development with automotive companies - recession
• 2009 began development for the truck trailer industry
• 2013 commercialized products for the truck trailer industry
• 2014 commited to re-enter the automotive industry
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The Company│ objectives
• Maximizing the efficiency of metal
• Develop a mass producible all-metal sandwich
• We engineer our technology to create the optimized material for a specific
industry application
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Application development
Application
requirements &
objectives
Computational
modeling
Final design
Prototype
development
Commercialization
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Testing
&
validation
Application development (2)
Application
requirements &
objectives
For example:
Physical requirements
• Weight
• Corrosion
Mechanical requirements
• Bending
• Shear
• Compression
• Puncture
• Durability
Objectives
• Cost
• Manufacturing
• Repair
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Application development (3)
Application
requirements &
objectives
test program
1. Basis material characterization
Computational
modeling
plasticity model
fracture model
calibration
validation
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material card
Application development (4)
Application
requirements &
objectives
1. Basis material characterization
Computational
modeling
2. Virtual engineering & optimizing
Considering ductile fracture during
forming
0
Damage
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1
Application development (5)
Application
requirements &
objectives
1. Basis material characterization
Computational
modeling
2. Virtual engineering & optimizing
3. Development of material models
Macroscopic constitutive modeling for
shell elements
virtual experiments on microstructure
macroscopic constitutive model
IP #1
IP #2
IP #3
sandwich
4
n
3
1
2
composite shell element
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Application development (6)
Application
requirements &
objectives
Compression test
Computational
modeling
Prototype
development
Puncture test
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Application development (7)
Application
requirements &
objectives
Computational
modeling
Prototype
development
Bending test
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Application development (8)
Application
requirements &
objectives
Computational
modeling
Testing
&
validation
Prototype
development
→ Passed both stages
Test jig
Mock up
AAR test stage
1) 14,400lbs uniform pressure
2) 28,800lbs uniform pressure
Air bag
Bulge test: semi-trailer side wall
1)
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2)
Application development (9)
Application
requirements &
objectives
Computational
modeling
Prototype
development
Bulge test: semi-trailer swing door
AAR test stage
1) 20,400lbs uniform pressure
2) 35,700lbs uniform pressure
→ Passed both stages
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Testing
&
validation
Lightweight Sandwich Product Portfolio
CellTech Sheet
CellTech Panel
•
4 metal layers
•
Thin sandwich material
(≤ 3mm)
•
Brazing or adhesive
•
Excellent formability
•
Substitute for sheet metal
•
3 metal layers
•
Thick sandwich material
(> 3mm)
•
Adhesive
•
Limited formability
•
Used as flat panel
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CT Sheet│ formability
Initially flat
sandwich sheet
Deformed
sandwich sheet
No delamination
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CT Sheet│ formability (2)
Stamping test of an upper A-pillar inner reinforcement part
• Prototype samples proven to be stampable
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CT Sheet│ weldability
5mm
Process parameters:
• AC welding (60Hz)
• 11.8kA for 20 cycles
• Force about 2.5kN
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CT Sheet│ structural member
Axial crushing
25000
sandwich
conventional
Axial force [N]
20000
15000
10000
5000
0
conventional
sandwich
0
20
40
60
80
100
Displacement [mm]
• Energy absorption 70% higher for the same weight!
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120
CT Sheet│ structural member (2)
Bending
14000
sandwich
conventional
12000
sandwich
Force [N]
10000
8000
6000
4000
2000
0
conventional
0
10
20 30 40 50
Deflection [mm]
60
70
• Energy absorption 120% higher for the same weight!
• Sandwich sheets can carry much higher in-plane compressive loads before
and after buckling!
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CT Panel
Lightweight sandwich material for flatter industry applications
• High stiffness per weight
• Cost-efficient mass production
• Ability to use low cost galvanized steel sheets
• Bonding with a high performance aerospace grade structural adhesive
• 100% recyclable to be environmental friendly
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CT Panel│ bendable
Curved along width direction (radius = 1.0m)
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CT Panel│ bendable (2)
90° angle bend along width direction using a brake press
no delamination
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CT Panel│ corrosion
Bare galvanized steel
(G90)
G90 + corrosion
protection system
initial
1,000hrs salt spray
(ASTM B117)
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CT Panel│ application
Immediate Opportunity
Early Adoptors
Truck Trailer parts:
• Doors (swing and roll-up)
Truck Trailers
• Side walls
• Roofs
• Floors
Containers
Manufacturing partner
Construction
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CT Panel│ application (2)
“CellTech is a revolutionary material
for the trailer industry.”
VP-engineering
Mid America Truck Show (March 2013)
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CT Sheet & Panel│ considerations
• Type and gauge of metal, metal coatings, bonding method
• Low cost manufacturing process to deliver product
economics
• Most suitable industry applications
• Strategic partner(s) for joint application development
• Strategic partner for manufacturing
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CellTech & Steel Industry
• We are committed to help steel become a low cost, light
weight solution; outperforming other metals and composite
materials.
• With the proper steel, correct sandwich design,
manufacturing efficiencies and the appropriate selected
industry application =
Steel Can Become The Ultimate Light Weight Solution.
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Q&A
Thank you!
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