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James P. Bartlett
02-19-1991, 01:36 PM
Dear Biomch-l Readers,

I am a Ph.D. engineering candidate at North
Dakota State University, U.S.A. My dissertation
involves cortical bone fracture mechanics. If anyone
would like more information regarding this work, have
suggestions on funding sources (estimated at $3465.),
or perhaps be interested in critically reviewing the
proposal, please contact me.

I am also interested in learning of teaching,
research and post-doctoral positions for which this
work may be appropriate background. Please find the
dissertation title and abstract attached.

Thank you very much for your time!

Sincerely, James P. Bartlett
Graduate Teaching Fellow
Department of Mechanical Engineering
and Applied Mechanics
North Dakota State University
Fargo, North Dakota 58105, USA
(701) 237-8835


MICRO-STRESS CONCENTRATIONS AND CRITICAL STRESS
INTENSITY FACTORS OF CORTICAL BONE BY
FRACTIONAL FRINGE MOIRE' INTERFEROMETRY

The occurrence of accidental bone fracture together with
the increased demand for bone and joint prostheses with long term
reliability have made the evaluation of cortical bone critical
stress-intensity factors important. Cortical bone micro-
stress and fracture characteristics with their related
morphology are not fully understood which, as a matter of course,
results in sub-optimal prosthesis design.
Recently, the highly sensitive displacement field
measurement technique called fractional fringe moire'
interferometry (FFMI) was validated by Bastawros &
Voloshin, 1989. This technique has successfully
measured thermal strain in electronic packages and
determined mixed mode stress-intensity factors in PMMA
(plexiglass). The high sensitivity (.417 micron per
fringe order) of FFMI is the key to its usefulness in
studying cortical bone.
This work has two objectives. The first
objective is to measure micro-stress concentrations
around Haversian canals and osteons in bovine cortical
femoral bone using FFMI. From the location and
orientation of these stress concentrations, the number
of likely micro-fracture sites can be identified. The
second objective is to measure mode I critical stress
intensity factors in small specimens of bovine femoral
cortical bone and correlate these values to stress
concentrations. This will facilitate future studies
of critical stress-intensity in small human bones.