PDA

View Full Version : Summary of responses: G-force limits for head and neck(UNCLASSIFIED)



Gutekunst, David J Mr Usariem
06-18-2007, 10:50 PM
Classification: UNCLASSIFIED
Caveats: NONE

Biomch-L community,

Many thanks to all who responded to my colleague's question about
G-force limits for the head and neck. I have pasted the original
message and the numerous responses below. The responses were a great
help and have given our team a clearer picture of the work that has been
done in acceleration of the head and neck.

- Dave



Original post:

This question is on behalf of a colleague who is planning a new research
study:

"I am writing a research protocol on the response of the neck and head
to unexpected accelerations/decelerations. In order to get the study
approved, I must be able to state that the subjects will not be in
danger of injury. I thought about specifying that we will stay within
the acceleration limits for amusement park rides, but I have not been
able to find such limits. Does anyone have a reference that describes
safe limits for amusement park rides, or other relevant limits? I
understand that the criteria may be in terms of the first derivative of
acceleration (jerk) or the second derivative of acceleration (snap)."

Responses:

Dear Mr. Gutekunst:

The Bioastronautics Data Book, 2nd Edition (1973), NASA-SP-3006, has a
very good review of human tolerance limits to impact that is well
referenced. Chapter 6 in the book, entitled "Impact," reviews these
limits in all three axes (eyeballs in/out, eyeballs left/right, eyeballs
up/down). In particular the author cites aviation/aerospace-related
peak-Gs such as ejection seats, parachute openings, Apollo studies, etc
and does some comparisons with auto accidents, but does not mention
amusement park rides.

Unfortunately, I do not have an electronic version of the chapter, only
the hardcover book on my shelf. I hope this information helps, and good
luck with your studies!

Regards,
-Kevin

************************************************** ********
Kevin R. Duda, Ph.D.
The Charles Stark Draper Laboratory, Inc.
(617) 258-4385
kduda@draper.com
************************************************** ********


Dear Dave,

I might be wrong but I think that all loading in amusements park is
expected rather than unexpected. I have done some work on the
biomechanics of the neck back in Bristol quite recently and was always
interested in what you are trying to do. I remember having a brief
discussion with Jim Potvin at the ESB meeting in 2004 and he mention a
study he was planning to do on kids riding and bumping these little
electric cars in amusements park. You can maybe try to contact him.
I am doing my second postdoc now in the area of motor control but I will
be happy to talk to you about possible issues regarding your study if
you wish (tel. 814-863-0995).
All the best,
Andrzej
Andrzej Przybyla [asp14@psu.edu]

-------------------------------------

Dear David:

A customer of Delsys (Erica Doczy) from WPAFB did something in the area
of G-force. I have copied Erica in my email. I am sure she will shed
some light.

Take care,

Devi Bheemappa
Manager, Sales and Marketing
Delsys Inc.
617 236 0599 xt.231 - (P)
617 236 0549 - (F)
devi@delsys.com
www.delsys.com

-------------------------------------

I know an investigator at the University of Guelph, Dr. Jim Dicky is
running a whip lash simulation.
I hope that helps.

Jon

Cyril J. Donnelly
MSc Candidate 2007
UW Biomechanics
Waterloo, Ontario, Canada
jondonnelly32@hotmail.com

-------------------------------------

Dave,

We had some investigators looking at acceleration of the brain during
heading soccer balls. They were accelerating the head, and had to find
these allowable limits. The two mechanical engineering professors that
were working on it were Phil Bayly, and Guy Genin. I have CC'ed them on
this response.

Joe

Joseph W. Klaesner, Ph.D.
Assistant Professor
Program in Physical Therapy
Department of Biomedical Engineering
Washington University School of Medicine Campus Box 8502
4444 Forest Park Blvd.
St. Louis, MO 63108-2212
(314) 286-1436
(314) 286-1410 (FAX)
email: klaesnerjw@wustl.edu

-------------------------------------

Hello David,

Attached are some links that should help you on this question and our
data sheet for an accelerometer that can be used for this type of
testing.
http://www.astm.org/SNEWS/AUGUST_2003/hudson_aug03.html
http://www.saferparks.org/are_rides_safe/dynamic_force/g_force_primer.ph
p
http://www.google.com/search?hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1
&q=amusement+ride+acceleration+testing&spell=1

Best regards,

Paul Bussman
paul.bussman@kistler.com
___________________________________
Kistler Instrument Corp.
75 John Glenn Drive, Amherst, NY 14228-2171, USA Tel +1 716 691 5100
(direct 716 213 5781) Fax +1 716 691 5226

-------------------------------------

David: Have you seen the paper by Smith and Meaney on roller coasters?

Smith, D. H., and Meaney, D. F., 2002, "Roller coasters, g forces, and
brain trauma: on the wrong track?," J Neurotrauma, 19(10), pp.
1117-1120.
--
Kenneth L. Monson, Ph.D.
Department of Neurological Surgery
University of California, San Francisco

1001 Potrero Ave., Bldg. 1, Rm. 101
San Francisco, CA 94110
(415) 206-8094
kenneth.monson@ucsf.edu

-------------------------------------

ASTM F-2291 standardizes design accelerations for amusement rides and
goes into jerk in a very minor way. I am aware of no standards for snap
(nor crackle or pop, which I believe are the 4th and 5th derivatives). I
would think for anything resembling an impact-type pulse that processing
accelerometer signals would be difficult.

You should also look into some everyday and bumper car studies:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dop
t=AbstractPlus&list_uids=9455663&query_hl=1&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dop
t=AbstractPlus&list_uids=8073323&query_hl=3&itool=pubmed_docsum

http://www.sae.org/technical/papers/2006-01-0247

-Bill
------
William Bussone
bussone@vt.edu

-------------------------------------

I know that theme parks often brag about the g-forces of their coasters.
Some quick googling got me this:

http://themeparks.about.com/od/coasterridereviews/fr/apolloschariot.htm
"up to 4.1 Gs"

http://www.fearandloafing.com/features/rollercoaster.html
This one discusses five coasters and breaks down the accelerations by
direction.

http://www.journalism.umd.edu/cns/wire/2002-editions/05-May-editions/020
502-
Thursday/KillerCoasters_CNS-UMCP.html
"Several new coasters boast top speeds of 100 mph and hold G-force
ratings
-- a measure of the amount of acceleration force exerted on a body -- at
6.5, more than the maximum 4 G's that astronauts feel while traveling up
to 17,440 mph on liftoff, according to a 2002 article in the Annals of
Emergency Medicine."

>From this article it sounds like some correctly-functioning roller
coasters may actually be able to kill people and that there are
currently no limits on the accelerations they can impart. The article
looks into this further:
http://www.neuroskills.com/pr-coasterbia.shtml
My impression is that the litigious and thrill-seeking aspects of our
society are on a collision course with this...

Could you measure accelerations of some everyday activities and
demonstrate that you will be subjecting them to something similar to
what they would normally experience in everyday life?

Brian Schulz, Ph.D.
Program Specialist
VISN 8 Patient Safety Research Center (118M) James A. Haley Veterans'
Hospital
11605 North Nebraska Ave.
Tampa, FL 33612-5738
Phone: (813) 558-3944
Fax: (813) 558-3990
www.patientsafetycenter.com

-------------------------------------

Dave - did you ever get a response to this? If not, Shrawan Kumar has
done alot of whiplash testing that has passed IRB. Most studies keep
the accel/decel. to a delta V of about 5 mph.

Al
Al Vangura Jr. [avangura@hotmail.com]


-------------------------------------------------------

David J. Gutekunst, M.S.
Research Physiologist
Biomechanics Team, Military Performance Division
U.S. Army Research Institute of Environmental Medicine
Natick, MA 01760-5007
Phone: 508.233.4888
Fax: 508.233.4195
Email: david.gutekunst@na.amedd.army.mil
Classification: UNCLASSIFIED
Caveats: NONE