Biomedical Engineering Reference
In-Depth Information
0.0
-5.0
-10.0
-15.0
-20.0
-25.0
-30.0
-35.0
-40.0
-45.0
Sample A1
Sample A2
Sample A3
Sample A4
0.001
0.010
0.100
1.000
Frequency, kHz
FIGURE 7.14
Wet IPMNC impedance phase.
1000
900
800
700
600
500
400
300
200
100
0
10
-2
10
-1
10
0
10
1
10
2
Frequency, kHz
FIGURE 7.15
PZT frequency response magnitude.
practical limits to how low this frequency may be set. In general, subhertz condi-
tioning with a piezoelectric element is rare and difficult to achieve.
Figure 7.16 is the frequency response magnitude of the IPMNC patch under
cantilever excitation.
The voltage magnitude of the IPMNC output is much lower than that of the
piezoelectric element, although a fair comparison cannot be made from these data since
they were actuated in different modes. However, note that the break frequency for the
IPMNC cantilevered beam occurs at approximately 0.03 Hz. This is significantly better
than the 10-Hz break frequency for the comparably sized piezoelectric patch for low-
frequency accelerometer applications. Recall that this low break frequency was achieved
