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Alex Depaula
01-26-2001, 05:35 AM
Dear list members:

There were only a few replies to my question concerning impact testing of
cortical bone, but there was some interest in reading the responses.

Here is the original request:

>===== Original Message From alex_depaula@mtf.org =====
>Dear Biomechanics list:
>
>I am looking for information about falling-mass impact testing of cortical
>bone or people with knowledge of impact testing of bone. Any type of
impact
>testing information could also be helpful (Izod, Charpy or other).


Here are the 3 replies:

#1)

Dear Dr. DePaula:

We have been impact testing bare bones and intact specimens for 15 years in
our laboratories. However, we do not do the classical "metallurgical" types
of test (Izod, Charpy, Rockwell, etc.). Our primary interest has been to
study failure thresholds (e.g. force, energy, etc.) for various bones and
intact specimens in order to understand mechanisms of injury and
biomechanical
design criteria. We have used accelerator-cart/guiderail systems and
various
drop towers in our research. Is there some specific information that you
need? I would write more, but I am not sure what kind of information you
are
looking for... Do you want data? Are you interested in experimental
methodolgy? Let me know, and I will see if I can help more.

Sincerely,

Tyler Kress, Ph.D.
Associate Director
Engineering Institute for Trauma & Injury Prevention
The University of Tennessee

Tyler A. Kress, Ph.D.
The University of Tennessee
(865)974-3333


#2)
Yamada in Evans (Ed) Strength of Biological Materials, Williams and Williams
pub. 1970 lists the impact snapping strength of femoral cortical bone for
adult human, horse, bovine in the radial and tangential directions. These
data were collected using an Izod impact machine. Values are in lbf/in^2
(mean +- SD):
Human radial (12.13 +- 1.35)
Human tangential (8.87 +- 0.98)
Horse radial (10.27 +- 0.89)
Horse tangential (10.73 +- 0.93)
Bovine radial (9.80 +- 0.65)
Bovine tangential (11.20 +- 0.84)

Hope this helps.

Richard Kent
University of Virginia


#3)
Alex,

We have been interested in more rigorously discriminating comminution
patterns in high-energy injuries, based on fracture energy absorption. To
create fractures in cortical bone segments, we use a drop tower apparatus
that was constructed in our lab. We have also conducted tests of energy
absorption in cortical bone beam specimens using a Balanced Hounsfield
Impact Tester. (Some of this data is published in Beardsley et al, The Iowa
Orthopaedic Journal, 20:24-30, 2000). I am also aware of an early paper by
Bonfield and Datta (Journal of Applied Physics, 37:869, 1966) that reports
on the fracture behavior of short beam compact bone specimens in a
traditional Charpy test.

I would be interested in reading other responses that you receive regarding
this matter.

Regards,

Christina Beardsley
---------------------------------
Christina L. Beardsley
PhD candidate
Orthopaedic Biomechanics Lab
University of Iowa

______________________
C. Alex DePaula, Ph.D.
Product Development Scientist
Musculoskeletal Transplant Foundation
125 May Street, Suite 300
Edison, New Jersey 08837
Direct: 732-661-2261
Fax: 732-661-2360
Email: alex_depaula@mtf.org

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