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J.lane
06-04-1996, 12:31 AM
Hi,

Following my posting of replies re: flesh simulants, I have recieved some
more ideas. I think the most useful approach will be for us to use a
combination of leather and gel. Cheers Zach!! The target does not have to
mimic skin exactly as it will be covered by an anti-stab vest anyway but
I guess the results will be more accurate if we use a target which is as
realistic as possible.
As some people out there were interested in the results of my
query I thought it might be useful to post a second summary. Thanks once
again everyone!

Judith Lane
University of Strathclyde.
Glasgow.
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Hi Judith:

The replies you received on your query of "flesh simulants" was rather sparse!

Back it the late 1960's, PhD student Jim North and I at the University of
Strathclyde evaluated "chamois leather" against human skin. It provided a
"good" representation of the dynamic non-linear characteristics of human
skin (creep and stress relaxation). Not surprising considering it is still
the basic fibre-composite and contains a number of the original
glycoproteins . . . But the main point is that it's "clean" and readily
available.

Finlay, Evans, North, Gibson & Kenedi (1972). Dynamic and structural
characteristics of human skin: a comparative study with chamois leather.
Proceedings of the 18th Annual Technical Meeting of the Institute of
Environmental Sciences, held in New York, May 1972; pp. 94-111. Copies
available from IES, 940 East Northwest Highway, Mt. Prospect, Illinois 60056.

At that time, John Evans and the Tissue Mechanics folk at Strathclyde were
interested in the impact characteristics of tissues as they relate to
head-screen impacts in cars. The work may be referenced in Jim North's
thesis "Impact characteristics of human skin and subcutaneous tissue",
Strathclyde, December 1972.

I'm just off to Toronto for the week - job hunting. If you need a copy of
the paper, drop me a note and I will get to see it next weekend.

Best wishes:

Bryan Finlay
Professor (Part-time), Medical Biophysics
University of Western Ontario

61 Hampton Crescent 519-472-1346
London, Ontario 519-473-2645 FAX and Answering Machine
Canada, N6H 2P1 bfinlay@julian.uwo.ca

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Judith,

I read the summary on the flesh simulants. I can just add some
information. The address of "Limbs and Things" is:

Radnor Business Centre
Radnor Road Horfield
Bristol BS7 8QS England
tel : +44 0272 446 466
fax: +44 0272 446 222

Best Regards,

Dirk Twisk
---------------------------------------------------
Ir. Dirk Twisk
Biomechanics Section
Crash-Safety Research Centre
TNO Road Transport Institute
Delft, The Netherlands
email twisk@wt.tno.nl
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On Wed, 29 May 1996, j.lane wrote:

> Hi,
>
> My colleagues and I are investigating some of the kinetic and kinematic
> parameters involved in the action of stabbing someone with a knife. We
> are using a Vicon system to track the motions of the arm and upper
> body.The knife consists of a blade and a custom machined handle into
> which is inserted a pylon transducer.
>
Just curious, but what inspired this study? Forensics? Or something
else.

> Currently the target consists of a box of special plasticine which is
> supposed to mimic the properties of flesh and is the standard target for
> tests of this kind. However, we feel that the plasticine does not
> sufficiently simulate either skin or muscle and thus will significantly
> alter the force-time profile of the knife at impact.
>
I do know that the U.S. Marine Corps. use "dummies" which are supposed to
have the properties of human flesh for bayonnet drilling with their
recruits. Whether or not you can get information regarding these dummies is
another story entirely.

> I heard that there is a company somewhere, possibly in Europe, that
> produces a gel with similar properties to flesh. I have tried looking
> through the Biomch-l Yellow Pages and the Archives but have had no joy. Thus I
> wondered if anyone out there had come across anything similar or had any
> suggestions. We have thought of using an animal carcass but are very
> reluctant to follow this route.
>
The studies involving ballistics and the trajectory of the bullet(s) which
killed Kennedy were conducted at the Ballistic Research Lab in Aberdeen,
Maryland (USA). In this study, sheep carcasses were utilized to simulate
human flesh.

> Thanks for your time and I hope to hear from someone in the near future!
>
Not that I am going to be involved in such studies in the near future, but
I would be interested in finding out what you come up with. Best of luck.

> Judith Lane. e-mail:judith.lane@strath.ac.uk
> Research Assistant,
> Bioengineering Unit,
> University of Strathclyde,
> Glasgow,
> Scotland
>
Cheers,
Tim Niiler
University of Delaware Sports Science Lab
Biomechanics and Movement Sciences
niiler@strauss.udel.edu

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Hi Judith,

(I first read you subject line as Flesh Stimulants
- interesting diversion.)

You've probably decided on your final approach by
now, but on reading your summary I had this idea.

Cover a slab of gel with leather. Make sure the gel is
pretty thick, because it has to give under the impact.
If you are worried about the leather being too tough,
Courtney's group will be able to help you tan a piece
of defatted skin with minimal cross-linking.
(Cross-linking using formaldehyde, glutaraldehyde, etc.
is much the same as commercial leather tanning.)

Good luck

Zach.

-- Santosh Zachariah --

Center for Bioengineering [ph:usa (206) 685 3488]
Univ. of Washington, Box 35225 [fax: 543 6124]
Seattle, WA 98195, USA zach@limbs.bioeng.washington.edu
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