15 - Hot Stamped bumper design.pdf

8/14/2019 15 - Hot Stamped bumper design.pdf

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w w w . a u t o s t e e l . o r g Page 1

Dr . A c h im K r o e n in gBenteler Automotive

- Structures -

H o t S t am p e d b um p e r d e s i g nchallenges in development for meeting multi-regional

(new) requirements.


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AgendaAgenda

Bumper Technology and Customer PortfolioBumper Technology and Customer Portfolio

The Hot Stamping ProcessThe Hot Stamping Process

-- Material, Process, Performance, DesignMaterial, Process, Performance, Design

Challenges in the bumper development for multi regionalChallenges in the bumper development for multi regional

requirements :requirements :

-- Europe (Changes, effect and conclusion)Europe (Changes, effect and conclusion)

-- North America (Changes, effect and conclusion)North America (Changes, effect and conclusion)


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1) UHSS Hot Formed Bumper

2) UHSS Cold Formed Bumper

3) Aluminium Bumper Extruded

4) TRB Bumper

5) UHSS/HSS Roll Formed Bumper

6) Magnesium Bumper(Customer Project)

7) Tube Bumper

8) Plastic or Hybrid Bumper(R&D project)

1) UHSS Hot Formed Bumper

2) UHSS Cold Formed Bumper

3) Aluminium Bumper Extruded

4) TRB Bumper

5) UHSS/HSS Roll Formed Bumper6) Magnesium Bumper

(Customer Project)

7) Tube Bumper

8) Plastic or Hybrid Bumper(R&D project)

Benteler Bumper Solutions

t = 3,0 mm

t = 2,5 mm

t = 2,2 mmt = 2,5 mm

t = 2,2 mm

t = 3,4 mm


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Developed for US/Canadarequirements

Developed for US/Canadarequirements

Benteler US-Bumper Examples in Production



indirect process

coil blank furnace handling

presspress(pre-forming /

trimming) cooling

direct process

coil blank furnace handlingpress

cooling

The Hot Stamping process


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Crash Performance of DB200 Hot Stamped



BMW E63 Rear BumperPeugeot 407 Front Bumper

High Design Flexibili ty with Hot Stamped design



AgendaAgenda

Bumper Technology and Customer PortfolioBumper Technology and Customer Portfolio

The Hot Stamping ProcessThe Hot Stamping Process

-- Material, Process, Performance, DesignMaterial, Process, Performance, Design

Challenges in the bumper development for multi regionalChallenges in the bumper development for multi regional

requirements :requirements :

-- Europe (Changes, effect and conclusion)Europe (Changes, effect and conclusion)

-- North America (Changes, effect and conclusion)North America (Changes, effect and conclusion)


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European low speed Test Specifications

ECE R42

Offset BarrierPendulum Tests

AZT Test

Thatcham

modifi

ed

AZT changesold new

front Barrier angle 0 10

Position Driver sideDriver + pas-

senger side

rear Barrier angle 0 10

Barrier mass 1000kg 1400kg

Position Driver side

Driver + pas-

senger sideRemark: High speed and towing requirements not listed


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ConclusionsA change of the barrier angle has a large effect on the bumper design

Due to the 10 barrier angle, the barrier directly hits the crash box.

The function of the crash box has increased, resulting in moreenergy taken over by the crash box.

The function of the beam is solely to connect the left and the rightside rail.

The total dimension of the beam has decreased due to the loss offunction.

The test can be done on driver and passenger side - non symmetricdesign has no longer benefit

Rear test only:

The increase of mass leads to 40% more energy input

Remark: Thatcham and AZT are discussing to place a low speed test - similar to the IIHS criteria

ECR 42 Pendulum test with only 4.0km/h for center and 2.5km/h for corner testing and

only one pendulum layer has no big effect on the bumper design and is even not neededto release the car in the market.

Old AZT

8,0 kg

New AZT

5,4 kg

Design change fromold to new AZT

European low speed Test Specifications


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Nissan Murano vs Micra Cut Away

Source: Thatcham

Mismatch Example

Nissan Murano vs Micra - Impact

Result: About 5.000$ repair cost on the Micra


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North American low speed Test Specifications

CMVSS 215

USPart 581

Pendulum Tests

IIHS

Barrier 30- / Pole Test

CMVSS 215

US Part 581

IIHS

Barrier 0

30

modifi

ed

Full Frontal test Front corner Test

Barrier height 457 above ground 406 above ground

Test Speed 10km/h 5km/h

Overlapcenter barrier in Y0

position

15% overlap

to the car

New IIHS front and rear setup

Remark: High speed and towing requirements not listed


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Stiff bumper is needed to reduce risk of under or over run.Due to this requirement, the weight wil l increase.

Shape and density of foam have a big influence on the system performance.

Weak crash box/bumper connection can cause problems in deformation performance.

Different results between ful l car models and component models possible.- movement of component cart could be more than 30mm in Z-direction.

More than 60% coverage between bumper and barrier is necessary. Bumper front cover height proposal: between 110 and 130mm minimum.

Complete car model to be taken for FE analysis or

- add damping systems values to crash cart

- add outer skin and foam to crash cart along with repair to the car- exact definit ion of posit ion between bumper and barrier- Center of gravity, inertia tensor, axle position

to be completed as more results are available!

Conclusion (IIHS bumper test)Don tmisspendulumoverlapfor2

layerCMVSS215test

North American low speed Test Specifications


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En d o f Pr e s e n t a t i o n T h a n k Y o u

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15 - Hot Stamped bumper design.pdf