Biomedical Engineering Reference
In-Depth Information
Table 2 Elastic properties measured in monotonic tests using micro human cortical bone
specimens
Bone
Test
Modulus (GPa)
Tissue type
References
Femur
Tension
3.9-11.7
Osteons
[
67
]
Compression
3.3-9.3
Osteons
[
68
]
Torsion
17.2-23.2
Osteons
[
69
]
3pt-Bending
2.3-2.7
Osteons
[
153
]
Tibia
3-pt-Bending
5.4
Micro-beams
[
154
]
4pt-Bending
6.8
Micro-beams
[
155
]
Fig. 8 Modulus loss of
human cortical bone in both
tension and compression
along the long axis of middle
aged human cadaveric tibias
macroscopic level [
69
]. Further, within each testing mode, scatter of elastic
modulus values is evident and most likely attributable to the varied degree of
mineralization of the osteons that have different biological ages, and the alter-
nating orientation of collagen fibrils in the osteons. Finally, nanoindentation
experiments produced measures of lamellar elastic moduli for human cortical bone
(average value of 17.7 ± 4.0 GPa for osteons and 19.3 ± 4.7 GPa for interstitial
bone tissue) [
70
].
3.2.2 Modulus (Stiffness) Loss
A decline (loss) of elastic modulus (stiffness) is well documented in fatigue tests
of bone, in which damage accumulates with increasing cycle number [
71
-
75
].
In addition, recent studies using a progressive loading scheme indicate that the
elastic modulus of human cortical bone decreases exponentially with the applied
strain for both tension and compression (Fig.
8
). In general, it is well accepted that
the modulus loss is due to micro damage accumulation in bone, which is largely
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