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The Effects of Variable Mass and Geometry, Pretwist, Shear Deformation and Rotatory Inertia on the Resonant Frequencies of Intact Long Bones: A Finite Element Model AnalysisThe influence of pretwist, nonuniformities in mass and flexural stiffness, rotatory inertia and shear deformation on the natural frequencies of intact bones is evaluated by means of a linear elastic, finite-element model which has been programmed for solution on the digital computer. Theoretical results are compared to the results on the forced vibration of intact canine radii obtained experimentally by Thompson. Surprisingly, inclusion of fairly large pretwist angles (from -14 to 12 deg for one specimen) had little affect on the first three frequencies of transverse vibration in either the cranial or lateral directions. Inclusion of shear deformation reduced the third-mode frequency in the stiffest (lateral) direction by about six percent, otherwise shear deformation played a minor role in determining natural frequencies. Similarly. rotatory inertia had negligible influence up to the third natural frequency. The predominant influence on the first three natural frequencies of transverse vibration could be attributed to the variations in mass and flexural stiffness along the length of the test specimens. Different effective moduli of elasticity are required to yield correct absolute values for the frequencies which correspond to experimental findings. thus implying the presence of some inhomogeneities in material properties around the bone cross-section and/or along its length.
Document ID
19990034128
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Young, Donald R.
(NASA Ames Research Center Moffett Field, CA United States)
Orne, David
(Wayne State Univ. Detroit, MI United States)
Date Acquired
August 19, 2013
Publication Date
June 21, 1976
Publication Information
Publication: Journal of Biomechanics
Publisher: Pergamon Press
Volume: 9
Subject Category
Aerospace Medicine
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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