comparative performance of racing head and neck restraints gregg s. baker, p.e. general technical...

Comparative Performance of Racing Head and Neck Restraints

Comparative Performance of Racing Head and Neck Restraints

Gregg S. Baker, P.E.

General Technical Properties, LLC

Orlando, Florida USA

(SAE Paper #2006-01-3631)

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Project Resources

•General Technical Properties, LLC–Intellectual Property Company

•Patents, Trademarks and Copyrights–Applications since 1987

•Biomechanics–Structural implants

»Spinal/craniofacial reconstruction systems»Arthroplasty devices (artificial joints)

–Linear accelerator targeting systems (radiosurgery)–Electronically controlled implants

•Fastening systems•IC Engine valve designs•WEB-based mass customization software

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Resources (Cont.)

•Outside Consultants-Rod Henry, P.E. – General Dynamics

•“High impact devices”

-Leon Kazarian, Ph.D.• NASA, U.S. Air Force and Navy (ejection seats, carrier landings, helicopter crashes, Shuttle Challenger post mortem)

-Wayne State University, Bioengineering Center

-Delphi Safety Systems

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The Safety Progression

1. That’s racing

2. “This should work”

3. Serious efforts

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Nothing we can do…

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“Hey ya’ll, watch this!”

Serious (?) EffortsSome Recent Ideas

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How well do they perform?

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The First Crash TestGeorge White, 1980

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Products that have been tested

<2004

•White Device

•HANS

•Hutchens

•D-Del

•Isaac

•Wright

•Tucker

>2004

•Isaac Link

•R3

•Hutchens II

•Hybrid

•Leatt Brace

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Previous Efforts

• SAE paper #2002-01-3304, “Sled Test Evaluation of Racecar Head/Neck Restraints”

• SAE paper #2004-01-3516, “Sled Test Evaluation of Racecar Head/Neck Restraints Revisited”

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SAE paper #2002-01-3304, “Sled Test Evaluation of Racecar Head/Neck Restraints”

• HANS device

• Hutchens device

• D-Cel device

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SAE paper #2004-01-3516, “Sled Test Evaluation of Racecar Head/Neck Restraints

Revisited”

• HANS device

• Hutchens device

• D-Cel device

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In the Perfect World…

• Every product

• Every test protocol

• Every load measure

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Plan B:

Get what you can and see what ya got

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Data Sources

• Peer-reviewed publications

• Unpublished raw test data

• Summary results from manufacturers

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Data Set

• Nine products

• 21 crash tests

• ~200 summary load measures

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Test Protocols(30 Degree Offset)

• Wayne State University Bioengineering Center “NASCAR” test

• Delphi Safety Systems Test Center execution of SFI Specification 38.1

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Wayne State

50G decelerating sled w/o head support, w/seat

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Wayne State Real Time

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Wayne State Slow Motion

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Delphi

70G accelerating sled w/o head support, w/o seat

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Delphi Real Time

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Delphi Slow Motion

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Performance Measures

• Loads-Axial (Tension/Compression)

-Shear

-Bending

• Head Gs

• Composite measures-HIC

-Nij, etc.

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Load Direction

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Wayne State

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SFI 38.1 at Delphi

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“Brain Slosh” references

• SAE Paper #2004-01-3539, Brain Injury Prediction for Indy Race Car Drivers Using Finite Element Model of the Human Head, L. Zhang et al

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Composite measures

FxDMyMocy *Where:

Where:

mD 01778.0

00.1Myc

Mocy

Fzc

FzNij

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What does it all mean?How do we add this up?

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Possible Options

1. Extend the Nij concept

2. Utilize fundamental stress analysis

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Option 1Extended Nij

?... Mzc

MzCmz

Myc

MyCmy

Mxc

MxCmx

Fzc

FzCfz

Fyc

FyCfy

Fxc

FxCfxN

Option 2Fundamental Stress Analysis

Does the load exceed the strength?

If so, we have BSF

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What’s the Strength?

Healthy 30-40 yo femur/tibia samples at room temp:

Ultimate Strength in Tension: 136-154 MPa

Ultimate Strength in Compression: 209-213 MPa

Source: Burstein, A.H. et al, J. Bone Joint Surg., 58A, 82, 1976

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What’s the Load?

1. Sum “F” and “M” values to determine axial loads.

2. Consider shear to resolve principle loads.

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OccipitalCondyles

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Fz

Mx

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Principle Stresses

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Conclusions

• Performance ~ f(1/length, stiffness)

• Dampers are magic

• Engaging the belt retains the belt

• Classic measures, while valuable, do not tell the whole story

• There is a significant need for simplification

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Acknowledgements

• Rod Henry, General Dynamics

• George White

• Jay Wright

• Wayne State Bioengineering Center

• Delphi Safety Systems Test Center

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Thank youhttp://www.isaacdirect.com/