Impact of the new regulation for Child

restraint systems on the crash

simulation

Sylvaine Pormenté

François Renaudin

23rd April 2013

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Corporate information

Dorel group

Juvenile brands portfolio

Overview of I-Size regulation

New regulation

4 Key points

Impact on simulation

Sled bench study

Dummy evaluation

Conclusion

Contents

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• Celebrating 50 years of innovation

• Headquarters in Montreal, Canada

• Approximately 5000 employees worldwide

• Operates in 22 countries

• $2.4 billion in sales, Sells to over 100

countries

• World’s largest juvenile products company

• U.S. market leader in recreational bikes

• #2 U.S. brand in RTA (ready to assemble)

home furniture

Dorel Industries Inc.

key brands

Strong Brand portfolio

I-Size regulation

• I-Size is a new regulation

– Increase the safety level for children in cars

– Improve ease of use for parents :

• Promote Isofix which facilitates child seat installation

• Force CRS manufacturer to adapte to child anthropometry

• Increase compatibility between child seat and cars

• Will be enforced by July 2013

• For a while, the current standard ECER44/04 will remain in effect for all belt installed child seats

• I-Size Phase 2 in progress for

– Booster seats

– Belted restraint products

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100 % Isofix

– 2 Anchorages and an anti rotation device

Top Tether or support leg

– No use of the adult safety belt

– Only harness to restraint children (integral system)

– External dimensions for compatibility with vehicle : Envelope for Rearward facing or front facing position

– Weight: MCRS + largest child < 33 kg,

Key points : Isofix

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Key points : Dynamic test

Side impact

• Specific pulse

• Intruding door with controlled door intrusion velocity

• Kinematics criteria:

– No head contact with door panel

– shall not exceeded a vertical plan on top of a door

• Injury criteria

New bench

• New cushion (foam, geometry)

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Key points : Crash Safety

– New Q dummies family will replace old P-dummies

– Additional criteria compared to R44

– Abdominal loading not available for phase 1 of i-Size regulation

– Rearward facing mandatory up to 15 months

To be reviewed within 3 years following entry into force of this regulation /

Frontal impact Side impact

5,2t

t12

12 adttt

1)tt(HPC

2

1

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Key points : new classification

• Classification of CRS

– Classification by stature

– CRS dimensions: in accordance with internal and external envelopes

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Integration in simulation of the new I-Size constraints

to be more predictive to validate CRS design

in terms of integrity but also in terms of performance

Need to have robust, reliable and validated tools for the I-size context

Calibration and validation of the environment of the CRS

– Foam of the new bench seat

– Side impact door padding.

Validation of the representativity of the Q dummies

– the global and local behaviour

– Need to reduce boundaries conditions influence

Impact on crash simulation

10 Softwares environnement Altair HyperWorks 11,0 dummy radioss format

0,0

500,0

1000,0

1500,0

2000,0

2500,0

0,0 10,0 20,0 30,0 40,0Fo

rce

(N

)

Displacement (mm)

test

simulation loading

Environment : Bench foam modeling

2 / Dynamic Correlation

– Simple tests performed to represent CRS dynamic loading on the bench

Improved law

1 / Static Correlation

– Static foam law (force/displacement)

– Compression + hysteresis

Mass (kg) error %

25.6 1,7

30.1 -0,8

33.1 3,1 11

1 / Dummy test (Q3)

– With a standard installation on rigid seat

– Head data (acceleration and displacement): the simulation shows a

conservative result against the test

The validation requirements (certification) of these models seems not

cover the loadcase observed in I-Size use.

Need to enhance the certification test matrix in collaboration with

Altair for the numerical aspects (through a Competitive Cluster

ProETech)

Dummy Evaluation

2 / Specifics tests

– Neck and Head evaluation in dynamic condition

– Strong harnessed dummy on rigid seat

– Dummy on rigid seat with a rigid shield

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Head form

Neck

Pendulum

Q3 neck/head segment Input data :

– frontal and lateral impact

– 4 m/s < velocity < 8 ms/s

Results

• Good correlation for low speed

• For 8m/s (value similar to frontal impact head velocity)

– Moment is overestimated (17%)

– 20% difference for HIC and neck force data

– The return motion of head is earlier in simulation

Dorel and Altair enhanced the material laws to improve the response of head / neck

DOE on material law based on neck certification test

responses : head rotation and neck moment

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Certification tests do not cover the range of velocities observed in tests

conducted by Dorel.

Q3 neck/head segment Initial Law

Improved law

Better behavior

Reduce gap

– Neck Moment

– Head Acceleration

– Head displacement

Reduce time shifting

– back and-forth motion

head

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Harnessed Q3 on rigid seat Input data :

Frontal Impact with I-size pulse - Steel rigid seat - Harness with hight pretension

3 steps : pretension / kinematic relaxation / desceleration

Results

- Strong Abdominal deformation

Possible causes

– Interaction between dummy and Harness

– Stiffness for

Thorax

Abdomen

Pelvis

– Initial dummy positioning

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40 ms

90 ms

130 ms

New test with rigid shield instead of harness

Futur work will focus on

abdomen and thorax stiffness investigation Strain rate influence

Q3 on rigid seat with rigid shield

– Not correlated kinematic

– Strong crushing area (abdomen)

The lack of abdomen stiffness disrupts the results

Not acceptable dummy behavior

40 ms

55 ms

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Conclusion

Altair Hyperworks tools are integrated in the development of our CRS products to validate design in terms of integrity but also in terms of performance

Working with performance criteria implies to know all the elements in interaction with the CRS.

The Need for improved Q dummy modeling

Collaboration with Altair and Humanetics to obtain a robust Q dummies family adapted to the I-size regulation

For both configuration: frontal and side impact

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ACKNOWLEDGEMENTS

Current study was supported by

French Ministry of Industry and Pays de la Loire Regional Council

Through the ProETech Competitive Cluster

In collaboration with Altair

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