Optimization Side Crash Performance Using a Hot-Stamped B-Pillar
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Transcript of Optimization Side Crash Performance Using a Hot-Stamped B-Pillar
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Optimization Side Crash Performance Using a Hot-Stamped B-Pillar
Bryan MacekBenteler Automotive
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Program Manager’s Slide
Highlights– Met all impact performance targets– 46% weight reduction versus baseline– No change to final assembly process– Cost effective solution
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Development Cycle
PerformanceTargets
Design of Record
Theory and Analysis
Design and Execution
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Test Criteria
• FMVSS 214 Dynamic Side Impact• FMVSS 214 Static Crush• IIHS Dynamic Side Impact
– Measures clearance between Centerline of steering wheel and B-Pillar inner
– Heavily dependent on B-Pillar performance– Most difficult to meet
IIHS side impact, courtesy http://www.iihs.org
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Dual Phase 5901.8 mm min. thk13.0 lbs.
Dual Phase 5902.3 mm min. thk.3.0 lbs
Design Solution (Baseline)
• Geometry– B-Pillar Reinforcement Assembly (16.0 lbs total)
• Main Stamping• Bulkhead at upper hinge / beltline• Hinge reinforcement at lower hinge
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• Clip Model– Created a component-level model of the b-pillar
assembly– Ran multiple iterations to optimize thickness
distribution
• Full Vehicle– Submitted best component designs to customer for
full vehicle FEA
Iteration Process
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Design Solution (baseline)
Passenger zone remains straight, protecting the occupant
Deformation zone absorbs energy safely away from occupant
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Design Methodology
• Energy Management– Structural Deformation
• High deformation load to limit intrusion• Controlled deformed shape to limit
intrusion– Reaction Movement
• Absorbs energy by moving vehicle• Even deformation load to limit deflection• High deformation load to increase
reaction movement
IIHS side impact, courtesy http://www.iihs.org
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Crash Energy Management
NewStylePillar
Old Style Pillar
Deflection
Force
The area under the Force Deflection curve is the amount of energy absorbed
ReducedIntrusion
Pushing the car away from the crash absorbs energy
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Hot Stamped DB2001.4 mm min. thk10.1 lbs
Dual Phase 5902.3 mm min. thk.3.0 lbs
Design Solution (Improved)
• Geometry– B-Pillar Reinforcement Assembly (13.1 lbs total)
• Main Stamping• Bulkhead at upper hinge / beltline• Hinge reinforcement at lower hinge
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Design Solution (Improved)
Passenger zone remains straight, protecting the occupant
Deformation zone absorbs energy safely away from occupant
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Possibilities for strategic strengthened hot formed parts
1-piece-designs
√
Advanced Design Options
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Design Solution (final)
• Materials– Hot Stamped DB200 Stamping)
• Yield = 950 MPa (+171%)• Tensile = 1300 MPa (+117%)• Elongation = 6% (-74%)
– HSLA 050 (Lower Stamping)• Yield = 345 MPa (-1.4%)• Tensile = 420 MPa (-30%)• Elongation = 22% (-4.5%)• Galvaneal for corrosion
resistance
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Design Solution (final)
• Materials– Thickness
• Upper Stamping = 1.3-1.6-1.9-1.0 mm(Tailor Rolled)
• Lower Stamping = 1.4 mm• 8.7 lbs total (-46%)
• Upper Stamping = 1.3-1.6-1.9-1.0 mm
1.3
1.6
1.9
1.0
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Advanced High Strength Steel
Overview of Steel Grades
0
2 0 0
4 0 0
6 0 0
8 0 0
1 0 0 0
1 2 0 0
1 4 0 0
1 6 0 0
1 8 0 0
0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5 5 0
E lo nga t io n , %
UTS,
MPa
.
DDQ, UDDQ
P, BH, IFHSHSLA
FB
DPTRIP
CPPM
HS
SU
HS
S
Mul
tipha
sest
eels
Mar
-te
ns.
CP = complex phasePM = partial martensiticDP = dual phaseFB = ferritic bainiticTRIP = transformation induced plasicityHSLA = high strength low alloyedP = rephosphorizedBH = bake hardeningIFHS = interstitial free high strengthDDQ = deep drawing qualityUDDQ = ultra deep drawing qualityBTR 165 = European Benteler gradeDB 200 = US Benteler grade
Tens
ile S
treng
th BTR 165 hot formed
BTR 165 as rolled
PH
SMaterials Overview Steel gradesMaterials Overview Steel grades
DB200Hot Stamped
DB200As Rolled
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• highest material strength with high ductility
• high potential of weight reduction
• best form accuracy
• no spring-back-effect
• complex geometries feasible
• excellent intrusion control in crash events
Benefit of Hot StampingBenefit of Hot Stamping
Hot Stamping Benefits
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Tailor Rolling Benefits
• Allows complete tuning of deformed shape• Allows weight reduction by removing low-stress
material• No stress risers from welded joints• Unlimited number of thickness changes
1,0 mm
1,0 mm
1,75 mm
1,3 mm
1,75 mm
1,6 mm
1,75 2,51,75
6,6 kg
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Processes
Hot Stamping Process
coil blank furnace handlingpresscooling
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0 100 200 300 400 500 600 700
Meßweg in mm
Ban
dd
icke
in m
m
gewalztes Bandprofil
Sollprofil
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
0 200 400 600 800 1000Meßweg in mm
Ban
dd
icke
in m
m
gewalzte BandkonturSollprofil
Tailor Rolling Process
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But can I weld it?
• Design for Manufacturability– Stamped design
• Requires no changes to mating parts• Requires no changes to assembly process
– Weldable• Requires no special weld capital• Requires no special weld testing
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Design Solution (final)
• Processes– Spot Welding
• No special equipment needed• Sufficient joint strength for crash
– Projection Welding• Ultra High Strength Steel allowed hinge tapping
plates to be replaced by simple weld nuts
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Design Solution (final)
Passenger zone remains straight, protecting the occupant
Deformation zone absorbs energy safely away from occupant
Deformation allowed in hot stamped material to increase energy absorption
base final
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You’ve seen this slide before
Highlights– Met all impact performance targets– 46% weight reduction versus baseline– No change to final assembly process– Cost effective solution
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Roof Rail-reinforcement
Doorbeam
A-Pillar-reinforcement
B-Pillar-reinforcement
Side member-reinforcement
Rear Bumper
Front BumperFront Bumper
BeltlineReinforcement
reinforcement
BeltlineReinforcementReinforcementReinforcement
Rocker Panel-reinforcementRocker Panel-reinforcement
Tunnel
Product Samples for Hot Stamping
MountingplateFront wall
CarrierUnderstructure
Other Applications
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• Questions & Answers
Questions and Answers