Biomedical Engineering Reference
In-Depth Information
T
0
= 10°C
T
0
= 20°C
T
0
= 30°C
T
0
= 40°C
0.016
0.012
e
0.008
0.004
0.000
0.0
0.5
1.0
1.5
2.0
2.5
t
(10
6
second)
FIGURE 3.5
Variation of
e
with time
t
for several temperatures (φ
b
− φ
a
=
p
=
P
=0).
• Case 4: φ
b
− φ
a
= -60, -30, 30, and 60 V,
r
=
b
0
, and
T
0
=
p
=
P
= 0
• Figure 3.6 shows the variation of
e
with time
t
for various val-
ues of electric potential difference with
T
0
=
p
=
P
= 0. It can be
observed from Figure 3.6 that there are no significant differences
between the remodeling rates when the external electric poten-
tial difference φ
b
− φ
a
changes from -60 to 60 V, though it is evi-
dent that the remodeling rate increases as the electric potential
difference decreases. However, the result does suggest that the
remodeling process might be improved by exposing a bone to an
electric field. Further theoretical and experimental studies are
needed to investigate the implication of this in medical practice.
• Case 5: φ
b
− φ
a
= -60, -30, 30, and 60 V,
p
(
t
) = 2 MPa,
P
(
t
) = 1500 N, and
T
0
= 0
• This loading case is considered in order to study the coupling
effect of electrical and mechanical loads on bone remodeling rate.
Figure 3.7 shows the numerical results of volume fraction change
against different values of electric potential difference φ
b
− φ
a
when
T
0
= 0,
P
(
t
) = 1500 N, and
p
(
t
) = 2 MPa. As already observed in
Figure 3.6, it can be seen from Figure 3.7 that the bone remodeling
rate increases along with the decrease of the potential difference
φ
b
− φ
a
. The combination of electrical and mechanical loads results
in significantly different values of the remodeling rate when differ-
ent electrical fields are applied.
