Biomedical Engineering Reference
In-Depth Information
fitting calculation could not reach convergent results due to the presence of
measurement errors. Thus, they used 10% of final fitting values of the two
parameters as the tolerance in the calculations, which meant that the relative
difference of the final fitting value with respect to each of the calculation
values (such as Δτ with respect to τ
d
12
or τ
d
23
or τ
d
31
) was below 10%.
9.5 Influence of Shear Stress on Bone Piezovoltage
As a continuation of Section 9.4, this section describes measurements of the
piezovoltage of bone between two surfaces of a bone beam under bend-
ing deformation. It summarizes the development reported in Fu et al. [23],
whose study found that the sign of piezovoltages depended on shear stress
only and was not sensitive to normal stress.
9.5.1 Methods
In the experiment, Fu et al. harvested cortical bone materials from the mid-
diaphysis of dry bovine (age 2-3 years) tibias and machined them into beam
samples with their axes aligned with the longitudinal direction of the diaph-
ysis (Figure 9.14a). Ten samples were prepared with the dimension range
Load
Loading beam
6
3
2
5
A
4
1
(b)
Load
Loading beam
7
8
(c)
(a)
FIGURE 9.14
Sample and electrode arrangements.
