Figure 1.
Flextensional hydrophones: (a) class I, (b) class III, (c) class IV, (d) class V, (e) class VI, and (f) class VII.
Figure 1.
Flextensional hydrophones: (a) class I, (b) class III, (c) class IV, (d) class V, (e) class VI, and (f) class VII.
Figure 2.
Class I flextensional hydrophone model, where
ts1 is the shell thickness,
is the flange radius,
ROC is the radius of the curvature of the shell,
is the piezoceramic disk thickness,
is the outer radius of the piezoceramic disk, and
is the inner radius of the piezoceramic disk. Refer to
Table 2 for detailed dimensions of the parameters.
Figure 2.
Class I flextensional hydrophone model, where
ts1 is the shell thickness,
is the flange radius,
ROC is the radius of the curvature of the shell,
is the piezoceramic disk thickness,
is the outer radius of the piezoceramic disk, and
is the inner radius of the piezoceramic disk. Refer to
Table 2 for detailed dimensions of the parameters.
Figure 3.
Class III flextensional hydrophone model, where
is the flange radius and
is the outer radius of the piezoceramic disk. The other parameters are the same as those in
Figure 2. Refer to
Table 3 for detailed dimensions of the parameters.
Figure 3.
Class III flextensional hydrophone model, where
is the flange radius and
is the outer radius of the piezoceramic disk. The other parameters are the same as those in
Figure 2. Refer to
Table 3 for detailed dimensions of the parameters.
Figure 4.
Class IV flextensional hydrophone model, where
ts4 is the shell thickness,
hs4 is the shell height,
is the semi minor axis length,
is the semi major axis length,
is the piezoceramic stack thickness,
is the insert width, and
is the piezoceramic stack width. Refer to
Table 4 for detailed dimensions of the parameters.
Figure 4.
Class IV flextensional hydrophone model, where
ts4 is the shell thickness,
hs4 is the shell height,
is the semi minor axis length,
is the semi major axis length,
is the piezoceramic stack thickness,
is the insert width, and
is the piezoceramic stack width. Refer to
Table 4 for detailed dimensions of the parameters.
Figure 5.
Class V flextensional hydrophone model, where
is the cavity apex radius,
is the cavity base radius,
is the piezoceramic disk radius,
is the cavity height,
is the piezoceramic disk thickness,
is the shell thickness, and
is the cavity apex radius. Refer to
Table 5 for detailed dimensions of the parameters.
Figure 5.
Class V flextensional hydrophone model, where
is the cavity apex radius,
is the cavity base radius,
is the piezoceramic disk radius,
is the cavity height,
is the piezoceramic disk thickness,
is the shell thickness, and
is the cavity apex radius. Refer to
Table 5 for detailed dimensions of the parameters.
Figure 6.
Class VI flextensional hydrophone model, where
is the cavity base radius,
is the cavity height, and
is the shell thickness. The other parameters are the same as those in
Figure 5. Refer to
Table 6 for detailed dimensions of the parameters.
Figure 6.
Class VI flextensional hydrophone model, where
is the cavity base radius,
is the cavity height, and
is the shell thickness. The other parameters are the same as those in
Figure 5. Refer to
Table 6 for detailed dimensions of the parameters.
Figure 7.
Class VII flextensional hydrophone model, where
ts7 is the shell thickness,
hs7 is the shell height,
is the flange half-width,
is the flange length,
is the insert width. Refer to
Table 7 for detailed dimensions of the parameters.
Figure 7.
Class VII flextensional hydrophone model, where
ts7 is the shell thickness,
hs7 is the shell height,
is the flange half-width,
is the flange length,
is the insert width. Refer to
Table 7 for detailed dimensions of the parameters.
Figure 8.
Variation in acoustic characteristics of the class I flextensional hydrophone according to the change in ROC: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 8.
Variation in acoustic characteristics of the class I flextensional hydrophone according to the change in ROC: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 9.
Variation in acoustic characteristics of the class I flextensional hydrophone according to the change in irp: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 9.
Variation in acoustic characteristics of the class I flextensional hydrophone according to the change in irp: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 10.
Variation in acoustic characteristics of the class I flextensional hydrophone according to the change in rf1: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 10.
Variation in acoustic characteristics of the class I flextensional hydrophone according to the change in rf1: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 11.
Variation in acoustic characteristics of the class I flextensional hydrophone according to the change in orp1: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 11.
Variation in acoustic characteristics of the class I flextensional hydrophone according to the change in orp1: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 12.
Variation in acoustic characteristics of the class I flextensional hydrophone according to the change in ts1: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 12.
Variation in acoustic characteristics of the class I flextensional hydrophone according to the change in ts1: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 13.
Variation in acoustic characteristics of the class IV flextensional hydrophone according to the change in tps: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 13.
Variation in acoustic characteristics of the class IV flextensional hydrophone according to the change in tps: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 14.
Variation in acoustic characteristics of the class IV flextensional hydrophone according to the change in wp: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 14.
Variation in acoustic characteristics of the class IV flextensional hydrophone according to the change in wp: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 15.
Variation in acoustic characteristics of the class IV flextensional hydrophone according to the change in hs4: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 15.
Variation in acoustic characteristics of the class IV flextensional hydrophone according to the change in hs4: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 16.
Variation in acoustic characteristics of the class IV flextensional hydrophone according to the change in ts4: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 16.
Variation in acoustic characteristics of the class IV flextensional hydrophone according to the change in ts4: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 17.
Variation in acoustic characteristics of the class IV flextensional hydrophone according to the change in lmin: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 17.
Variation in acoustic characteristics of the class IV flextensional hydrophone according to the change in lmin: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 18.
Variation in acoustic characteristics of the class V flextensional hydrophone according to the change in ts5: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 18.
Variation in acoustic characteristics of the class V flextensional hydrophone according to the change in ts5: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 19.
Variation in acoustic characteristics of the class V flextensional hydrophone according to the change in rcb5: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 19.
Variation in acoustic characteristics of the class V flextensional hydrophone according to the change in rcb5: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 20.
Variation in acoustic characteristics of the class V flextensional hydrophone according to the change in rp5: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 20.
Variation in acoustic characteristics of the class V flextensional hydrophone according to the change in rp5: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 21.
Variation in acoustic characteristics of the class V flextensional hydrophone according to the change in hc5: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 21.
Variation in acoustic characteristics of the class V flextensional hydrophone according to the change in hc5: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 22.
Variation in acoustic characteristics of the class VII flextensional hydrophone according to the change in hwf: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 22.
Variation in acoustic characteristics of the class VII flextensional hydrophone according to the change in hwf: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 23.
Variation in acoustic characteristics of the class VII flextensional hydrophone according to the change in hs7: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 23.
Variation in acoustic characteristics of the class VII flextensional hydrophone according to the change in hs7: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 24.
Variation in acoustic characteristics of the class VII flextensional hydrophone according to the change in ts7: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 24.
Variation in acoustic characteristics of the class VII flextensional hydrophone according to the change in ts7: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 25.
Variation in acoustic characteristics of the class VII flextensional hydrophone according to the change in lf: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 25.
Variation in acoustic characteristics of the class VII flextensional hydrophone according to the change in lf: (a) peak RVS frequency and bandwidth, (b) RVS at 100 Hz.
Figure 26.
Optimal design process for a flextensional hydrophone of each class.
Figure 26.
Optimal design process for a flextensional hydrophone of each class.
Figure 27.
RVS spectra of the optimized flextensional hydrophone models of different classes.
Figure 27.
RVS spectra of the optimized flextensional hydrophone models of different classes.
Table 1.
Properties of the materials constituting the flextensional hydrophones.
Table 1.
Properties of the materials constituting the flextensional hydrophones.
| Rubber | Aluminum | Steel |
---|
Density (kg/m3) | 1100 | 2710 | 7500 |
Longitudinal velocity (m/s) | 700 | 5850 | 6139 |
Shear velocity (m/s) | 10 | 3127 | 3281 |
Table 2.
Dimensions of the class I flextensional hydrophone basic model.
Table 2.
Dimensions of the class I flextensional hydrophone basic model.
Structural Parameter | Dimension (mm) |
---|
Shell thickness () | 3.5 |
Flange radius () | 30.0 |
Radius of curvature of the shell (ROC) | 450.0 |
Piezoceramic disk thickness () | 5.8 |
Outer radius of piezoceramic disk () | 12.0 |
Inner radius of piezoceramic disk () | 5.0 |
Table 3.
Dimensions of the class III flextensional hydrophone basic model.
Table 3.
Dimensions of the class III flextensional hydrophone basic model.
Structural Parameter | Dimension (mm) |
---|
Flange radius () | 35.0 |
Outer radius of piezoceramic disk () | 20.0 |
Table 4.
Dimensions of the class IV flextensional hydrophone basic model.
Table 4.
Dimensions of the class IV flextensional hydrophone basic model.
Structural Parameter | Dimension (mm) |
---|
Shell thickness () | 7.0 |
Shell height () | 27.0 |
Semi minor axis length () | 15.0 |
Semi major axis length () | 32.5 |
Piezoceramic stack thickness () | 4.6 |
Insert width () | 6.0 |
Piezoceramic stack width () | 4.6 |
Table 5.
Dimensions of the class V flextensional hydrophone basic model.
Table 5.
Dimensions of the class V flextensional hydrophone basic model.
Structural Parameter | Dimension (mm) |
---|
Cavity apex radius () | 5.0 |
Cavity base radius () | 23.0 |
Piezoceramic disk radius () | 30.0 |
Cavity height () | 2.0 |
Piezoceramic disk thickness () | 4.0 |
Shell thickness () | 3.0 |
Cavity apex radius () | 5.0 |
Table 6.
Dimensions of the class VI flextensional hydrophone basic model.
Table 6.
Dimensions of the class VI flextensional hydrophone basic model.
Structural Parameter | Dimension (mm) |
---|
Cavity base radius () | 18.0 |
Cavity height () | 3.5 |
Shell thickness () | 2.0 |
Table 7.
Dimensions of the class VII flextensional hydrophone basic model.
Table 7.
Dimensions of the class VII flextensional hydrophone basic model.
Structural Parameter | Dimension (mm) |
---|
Shell thickness () | 10.0 |
Shell height () | 40.0 |
Flange half-width () | 40.0 |
Flange length () | 21.0 |
Insert width () | 16.0 |
Table 8.
Optimal dimension of the design variables for each class of flextensional hydrophones.
Table 8.
Optimal dimension of the design variables for each class of flextensional hydrophones.
Class | Design Variable | Optimized Value (mm) |
---|
I | ts | 2.8 |
rf | 32.9 |
orp | 14.4 |
III | ts | 3.4 |
rf | 42.0 |
orp | 24.2 |
IV | ts | 7.2 |
hs | 32.4 |
lmin | 16.8 |
V | ts | 3.6 |
rcb | 26.0 |
hc | 2.4 |
VI | ts | 1.6 |
rcb | 18.4 |
hc | 3.9 |
VII | ts | 9.9 |
hs | 40.0 |
lf | 25.0 |
wf | 33.5 |
Table 9.
Acoustic characteristics of the optimized flextensional hydrophones of different classes.
Table 9.
Acoustic characteristics of the optimized flextensional hydrophones of different classes.
| Class I | Class III | Class IV | Class V | Class VI | Class VII |
---|
Peak RVS frequency (kHz) | 8.5 | 8.3 | 8.6 | 8.4 | 8.7 | 8.5 |
RVS at 100 Hz (dB) | −189.4 | −194.3 | −180.0 | −190.9 | −191.3 | −189.1 |
Bandwidth (kHz) | 5.7 | 6.9 | 7.6 | 4.8 | 5.0 | 6.2 |
Fractional bandwidth (%) | 67.1 | 83.1 | 88.4 | 57.1 | 57.5 | 72.9 |
Table 10.
Comparison of the acoustic characteristics of the class IV flextensional hydrophone and commercial hydrophones [
5].
Table 10.
Comparison of the acoustic characteristics of the class IV flextensional hydrophone and commercial hydrophones [
5].
| Average RVS Level Across the Receive Bandwidth | −3 dB Fractional Bandwidth |
---|
D/70/H | −205 dB | 62% |
T406 | −181 dB | 30% |
Class IV flextensional hydrophone | −179 dB | 88% |