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21st Century Roof Crush Solutions

Paul McKuneNoble International

Acknowledgements: Brandon Landino (Noble) and Sheng-Dong Liu (Generalety)


Roof Crush Model Major Roof Crush Components Next Generation Roof Crush Solutions

A. Upgage Only B. AHSS and Upgage

C. Hot Stamping D. A/B Pillar Tubes

E. Roll Formed Roof RailsF. Hydroformed Roof Rails

G. Hot Metal Gas Formed Roof RailsH. P-Tech Roof Rails

Laser Welded Blanks Conclusions

Agenda


Roof Crush Model

Previous Generation BOF SUV Unloaded Vehicle Weight > 4000 lbs Full Vehicle Model was obtained from Univ. of Kentucky and

enhanced for roof crush simulations

Model Set-up


Body Side Outer

D-Pillar Outer

C-Pillar Inner

A - Pillar Inner

B-Pillar Inner

Hinge Pillar Inner B-Pillar Outer

Hinge Pillar Outer

Major Roof Crush Components


Front Header Inner/Outer

Roof Bow #1Roof Bow #2

Roof Bow #3

Rear Header Inner/Outer

Roof Rail Inner

Major Roof Crush Components (cont.)


Internal Energy Animation


Key Components Baseline

Front Header Inner0.8 mm HS300 Roof Bow #1

2.2 mm HR HS300

Roof Rail Inner1.3 mm HS350

C-Pillar Inner0.9 mm HS250

A - Pillar Inner1.1 mm HS350

B-Pillar Outer1.6 mm HS350

Hinge Pillar Outer1.3 mm HS350

B-Pillar Inner1.0 mm Mild

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00

Displacement (Inch)

Roo

f Cru

sh R

esis

tanc

e

~ 1.5X GVW @ 3 Displacement


Front Header Inner1.4 mm HS300 Roof Bow #1

2.2 mm HR HS300

Roof Rail Inner1.6 mm HS350


A - Pillar Inner1.6 mm HS350

B-Pillar Outer1.6 mm HS350


B-Pillar Inner1.6 mm HS350

Option 1 Upgage Most Components

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00

Displacement (Inch)

Roo

f Cru

sh R

esis

tanc

e

baselineupgage-baseline

Vehicle Mass Addition: 5.15 kgImprovement: 27.7% @ 3Target: 67% @ 3 (2.5X GVW)


Front Header Inner1.4 mm DP600 Roof Bow #1

2.2 mm HR HS350

Roof Rail Inner1.3 mm DP600


A - Pillar Inner1.6 mm DP600

B-Pillar Outer1.6 mm Boron


B-Pillar Inner1.6 mm DP780

Option 2 Use AHSS and Upgage

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00

Displacement (Inch)

Roo

f Cru

sh R

esis

tanc

e

baselineAAHS-baselineupgage-baseline

Vehicle Mass Addition: 4.32 kgImprovement: 44.6% @ 3


Solution #1 AHSS + Hot Stampings

Front Header Inner1.2 mm DP600

Roof Bow #12.2 mm HS350

Roof Rail Inner1.8 mm Boron


A - Pillar Inner1.8 mm Boron




0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00

Displacem ent (Inch)

Roo

f Cru

sh R

esis

tanc

e

base lineBoron-base line3

Vehicle Mass Addition: 12.7 kgImprovement: 67% @ 3


Solution #1 Design Considerations

Can meet 2.5X GVW with no additional parts Excellent application for B-pillar Outer since both roof crush and side impact

performance are enhanced No changes to current assembly process Mass addition to vehicle is higher than other solutions Tooling and capital cost can be a factor This is the only solution that requires upgaging the C-Pillar to meet target


Solution #2 AHSS + A/B Pillar Tubes


2.2 mm HR HS350







A - Pillar Tube2.0 mm DP780

B - Pillar Tube2.0 mm DP780

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00

Displacement (Inch)

Roo

f Cru

sh R

esis

tanc

e

AHSS-baseline+ABtubebaseline

Vehicle Mass Addition: 8.0 kgImprovement: 72% @3


Solution #2Internal Energy Animation Comparison



B-Pillar Tube

A-Pillar Tube

Can meet 2.5X GVW with minimal mass addition to the vehicle

Prevents buckling at A/B Pillars More effective solution for cars than SUVs No changes to current assembly process Can be press-formed from AHSS or Usibor Low tooling cost


Solution #3 AHSS + RFRR + BP Tube


Roof Bow #12.2 mm HR HS350







RF Roof Rails1.6 mm M190


0 . 0 0 0 . 5 0 1 . 0 0 1 . 5 0 2 . 0 0 2 . 5 0 3 . 0 0 3 . 5 0 4 . 0 0 4 . 5 0 5 . 0 0

D is p la c e m e n t ( In c h )

Roo

f Cru

sh R

esis

tanc

e

A H S S -b a s e lin e + R F R R + B tu b eb a s e lin e



Solution #3 AHSS+RFRR+BP Tube









RF Roof Rails1.6 mm M190


0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00

Displacement (Inch)

Roo

f Cru

sh R

esis

tanc

e

AHSS-baseline+RFRR+Btube2baseline

Vehicle Mass Addition: 13.3 kgImprovement: 87% @ 3 (2.8XGVW)



Roll-formed Roof Rail

Roll-formed A-Pillar Reinforcement

Roll-formed M190 (Martensitic) UHSS No changes to current assembly process Need to be designed into vehicle early since constant

mating surface is required at weld flanges Secondary operations can be performed (sweep, holes, etc)

but should be minimized to reduce cost Low tooling cost


Solution #4 AHSS + HRR + BP Tube


2.2 mm HR HS350







HydroformedRoof Rail1.4 mm DP600

0 . 0 0 0 . 5 0 1 . 0 0 1 . 5 0 2 . 0 0 2 . 5 0 3 . 0 0 3 . 5 0 4 . 0 0 4 . 5 0 5 . 0 0


Roo

f Cru

sh R

esis

tanc

e

A H S S - b a s e lin e + H R Rb a s e lin e




Solution #4 AHSS + HRR + BP Tube










HydroformedRoof Rail1.6 mm DP600

0 . 0 0 0 . 5 0 1 . 0 0 1 . 5 0 2 . 0 0 2 . 5 0 3 . 0 0 3 . 5 0 4 . 0 0 4 . 5 0 5 . 0 0


Roo

f Cru

sh R

esis

tanc

e

b a s e li n eA H S S - b a s e li n e + H R R + B t u b e

Vehicle Mass Addition: 16.3 kgImprovement: 99.4% @ 3 (3XGVW)



Can form complex shapes for more flexible design Reduced part count DP780 is currently highest strength steel that can be Hydroformed Complex assembly process Freight cost is a factor Tooling and capital cost can be a factor

Hydroformed Roof Rail


Solution #5 HMGF Roof Rail









HMGF Roof Rail1.0 mm Boron




Solution #5 HMGF Roof Rail

Can form complex shapes for more flexible design Reduced part count Boron UHSS Complex assembly process Freight cost is a factor Improved tooling and capital cost compared to Hydroforming


Solution #6 - P-Tech Roof Rail + A/B Rnf









P-Tech Roof Rail1.0 mm Boron


RF A-Pillar Rnf1.2 mm M190

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00Displacement (Inch)

Roo

f Cru

sh R

esis

tanc

e

baselinePTtube+RFAP+Btube2




Most mass efficient solution Roll-formed Usibor UHSS Ends of constant closed section are press-formed after heating to ~ 920 deg C. Similar assembly process to Hydroformed Roof Rail Secondary operations can be performed (sweep, holes, etc) but should be

minimized to reduce cost Improved tooling and capital cost compared to Hydroforming or Hot Stamping


Hinge Pillar OuterA

B

Blank AThickness = 1.4 mmMaterial Utilization = 2.8 kg

Blank BThickness = 1.2 mmMaterial Utilization = 7.0 kg

Baseline Monolithic Rectangular BlankThickness = 1.4 mmTotal Material Used = 11.1 kg/veh

Total Material Used = 9.8 kg/vehMaterial Savings = 1.3 kg/vehWeight Savings = 0.8 kg/veh

Roof Rail Inner

Laser Welded Blanks

Baseline Monolithic Developed BlankThickness = 1.8 mmTotal Material Used = 13.7 kg/veh

A

B



Total Material Used = 11.1 kg/vehMaterial Savings = 2.6 kg/vehWeight Savings = 0.8 kg/veh


Laser Welded Blanks (cont.)

C-Pillar Inner


A

B



Total Material Used = 19 kg/vehMaterial Savings = 10.2 kg/vehWeight Savings = 4.8 kg/veh


B-Pillar Outer A

B Blank BThickness = 2.0 mmMaterial Utilization = 2.0 kg

C


Total Material Used = 15.6 kg/vehMaterial savings = 3.9 kg/vehWeight savings = 1.8 kg/veh

Blank CThickness = 1.6 mmMaterial Utilization = 4.9 kg


Laser Welded Blanks (cont.)

Baseline Monolithic Developed BlankThickness = 0.9 mmMaterial Utilization = 83 kg/veh

Body Side Outer A

B

C

Blank A DP500Thickness = 0.9 mmMaterial Utilization = 7.5 kg


Total Material Used = 70.4 kg/vehMaterial Savings = 12.6 kg/vehIndirect Weight Savings ~ 6.0 kg

Blank CThickness = 0.9 mmMaterial Utilization = 19.2 kg

LWB Savings Summary Total Mass Savings: 14.2 kg / Veh Total Steel Savings: 30.6 kg / Veh


A good body structure will add less than 8.0 kg to the vehicle to improve roof

crush resistance from 1.5 to 2.5X GVW, and less than 16 kg to improve roof

crush resistance from 1.5 to 3.0X GVW.

AHSS is necessary to meet new roof crush requirements at lower mass.

There are many roof crush solutions available and good results can be

achieved by using different combinations.

The P-Tech Roof Rail solution was the most mass efficient solution for the vehicle

tested and could be applied at a lower cost penalty than most other solutions.

Vehicle volume is an important factor in determining the best roof crush solution due

to tooling cost impact.

Much of the weight added to meet higher roof crush requirements can be taken

back out using Laser Welded Blanks at little or no cost penalty.

Conclusions


Thank You!!!Q/A



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21st Century Roof Crush Solutions - Steel Industry News .../media/Files/Autosteel/Great Designs in...

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