250-Hz transducer

Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
UDT Europe 2002 Conference
A Deep-Submergence, Very Low-Frequency,
Broadband, Multiport Transducer
19 June 2002
Alexander L. Butler and John L. Butler
Image Acoustics, Inc.
Cohasset, Massachusetts, 02025, USA
6/4/2005
UDT Europe 2002
1
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
LF
_
+
HF
Amplitude
Sum
f2
f1
180
Phase (deg)
90
0
f
-90
-180
6/4/2005
UDT Europe 2002
2
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Mass controlled, phase 180 deg
Summed response (+/- on ring)
Low Frequency
Resonator
Level
Stiffness controlled,
phase 0 deg
Piezoelectric
Ring
High Frequency
Resonator
FL
Added
Output
FH
Frequency
J. L. Butler, Multiport Underwater Sound
Transducer, U. S. Patent, 5,184,332 (1993)
Multiport Operation
6/4/2005
UDT Europe 2002
3
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
2L
2a
pa , u a
pL , u L
z
cos kz
2iρc
p ( z ) = −iρc
uL −
ua
sin kL
ka
1
pa = ∫ p( z )dz
L
6/4/2005
UDT Europe 2002
4
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
z2
z1
vL
va
Pa
z3
PL
General “T” network
6/4/2005
UDT Europe 2002
5
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
za
-Ca
va
vb
Pa
PL
Ca
Ca =
V
β
− iρc
za =
cot kL
2
πa
Resulting acoustical circuit
6/4/2005
UDT Europe 2002
6
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
ua
va
Fa
vL
Pa
uL
PL
FL
1 : πa2
2πaL : 1
Mechanical to Acoustical Transformers
6/4/2005
UDT Europe 2002
7
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
-C
ua
z
uL
Fa
C
FL
1 : a/2L
L
C=
βπa 2
z = −iρcπa 2 cot kL
Mechanical Equivalent Circuit
6/4/2005
UDT Europe 2002
8
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
FL = uL Z L
z
uL
-C
I
M
Cm
Ci
V0
ua
C0
1:N
2
1
 a 
Ci = C   =
β 4πL
 2L 
Combined Ring and Fluid Tube Equivalent Circuit
6/4/2005
UDT Europe 2002
9
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Outer
Ring Area
Transformer
Outer tube
transmission
line
Weighted
sum mixer
Input
Voltage
V
Electro-mechanical
transformer
Piezoelectric
Ring Driver
Inner
Ring Area
Transformer
Inner tube
transmission
line
Self and mutual
radiation
impedance
Equivalent Circuit
6/4/2005
UDT Europe 2002
10
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
600 Hz Design
One-third Scale Model to 200 Hz
Design
6/4/2005
UDT Europe 2002
11
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Transducer Dimensions
Length 32 in (813 mm)
Diameter 15 in (381 mm)
2 Ring Array
-33-mode
- 60 PZT-8 wedges / ring
- Diameter 9.8 in (250 mm)
- Height 8.6 in (220 mm)
600 Hz Multiport Finite Element Model
6/4/2005
UDT Europe 2002
12
Image Acoustics, Inc.,
1
97 Elm Street, Cohasset, Massachusetts 02025
3
2
5
4
5
6
6
10
7
11
8
8
1
2
4
20
13
12
21
14
9
23
10
7
22
15 16
11
15 16
14
24
17
12
17
27
18
18
19
13
25
19
26
600 Hz Multiport Equivalent Circuit
6/4/2005
UDT Europe 2002
13
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
150
Circuit Analysis
FEA
145
TVR (dB re 1uPa @ 1m)
140
135
130
125
120
115
110
105
100
0.5
0.6
0.7
0.8
0.9
1
1.1
Frequency (kHz)
600 Hz Multiport FEA and Equivalent Circuit TVR
6/4/2005
UDT Europe 2002
14
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Transducer Dimensions
Length 32 in (813 mm)
Diameter 15 in (381 mm)
2 Ring Array
-33-mode
- 60 PZT-8 wedges / ring
- Diameter 9.8 in (250 mm)
- Height 8.6 in (220 mm)
600 Hz Multiport Transducer
6/4/2005
UDT Europe 2002
15
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
600 Hz Multiport at Test Facility
6/4/2005
UDT Europe 2002
16
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
600 Hz Multiport Transducer
6/4/2005
UDT Europe 2002
17
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
150
Measured
Circuit Analysis
FEA
145
TVR (dB re 1uPa @ 1m)
140
135
130
125
120
115
110
105
100
0.5
0.6
0.7
0.8
0.9
1
1.1
Frequency (kHz)
Measured Transmitting Voltage Response for 600 Hz
Multiport Transducer
6/4/2005
UDT Europe 2002
18
Image Acoustics, Inc.,
TVR-TCR (dB re 1uPa/1A @ 1m)
210
97 Elm Street, Cohasset, Massachusetts 02025
fa1=645 Hz
fa2=1020 Hz
200
190
180
Tube Coupling Coefficient
Low Frequency Tube
K=0.3
High Frequency Tube
K=0.2
170
160
150
fr2=1000 Hz
fr1=615 Hz
140
130
120
110
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
Frequency (kHz)
600 Hz Multiport Measured transmitting current response
and TVR showing tube coupling coefficient
6/4/2005
UDT Europe 2002
19
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
225
220
SPL (dB re 1uPA @ 1m)
215
210
205
200
195
190
185
180
175
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
Frequency (kHz)
600 Hz Mulitport measured at 2000 volts
6/4/2005
UDT Europe 2002
20
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
TPR (dB re 1uPa/1w @ 1m)
175
170
165
160
155
150
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
Frequency (kHz)
Measured Transmitting Power Response for 600 Hz Multiport
Transducer
6/4/2005
UDT Europe 2002
21
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
1400
1200
uMHOS
1000
800
600
400
200
0
0.4
0.5
0.6
0.7
0.8
0.9
1
Frequency (kHz)
600 Hz Multiport Conductance
1.1
1.2
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
1600
1400
1200
uMHOS
1000
800
600
400
200
0
-200
0.4
0.5
0.6
0.7
0.8
0.9
1
Frequency (kHz)
600 Hz Multiport Susceptance
1.1
1.2
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
600 Hz Multiport Measured beam patterns at 615 Hz and 995 Hz
6/4/2005
UDT Europe 2002
24
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
200 Hz Design
Full Size Model
6/4/2005
UDT Europe 2002
25
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Steel Low
Frequency Tube
Steel High
Frequency
Tube
Transducer Dimensions
Length 97 in (2464 mm)
Diameter 29 in (737 mm)
Weight 2400 Lbs (1088 Kg)
PZT-8 Ring Array
200 Hz Multiport Finite Element Model
6/4/2005
UDT Europe 2002
26
Image Acoustics, Inc.,
1
97 Elm Street, Cohasset, Massachusetts 02025
3
2
5
4
5
6
6
10
7
11
8
8
1
2
4
20
13
12
21
14
9
23
10
7
22
15 16
11
15 16
14
24
17
12
17
27
18
18
19
13
25
19
26
200 Hz Multiport Equivalent Circuit
6/4/2005
UDT Europe 2002
27
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
TVR (dB re 1uPa @ 1m)
Finite Element
160
155
150
145
140
135
130
125
120
115
110
105
100
Circuit Analysis
180
200
220
240
260
280
300
320
340
360
Frequency (Hz)
Finite element and equivalent circuit transmitting response
6/4/2005
UDT Europe 2002
28
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
8 Ring Array
-33-mode
- 124 PZT-8 wedges / ring
- Diameter 20 in (508 mm)
- Height 28 in (711 mm)
Assembled Ring Array before Potting
6/4/2005
UDT Europe 2002
29
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Ring array after
polyurethane potting.
Array was rubber
booted for longevity
Assembled Ring Array after Potting and Rubber Molding
6/4/2005
UDT Europe 2002
30
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Ring array is seated at
the center of the high
frequency tube.
Transducer Being Assembled
6/4/2005
UDT Europe 2002
31
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Fully Assembled 200 Hz Multiport Transducer
6/4/2005
UDT Europe 2002
32
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
200 Hz Mulitport Transducer
6/4/2005
UDT Europe 2002
33
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
160
155
Finite Element
Circuit Analysis
TVR (dB re 1uPa @ 1m)
150
Measured without Equalizer
145
140
135
130
125
120
115
110
180
200
220
240
260
280
300
320
340
360
Frequency (Hz)
200 Hz Multiport Measured transmitting voltage response
6/4/2005
UDT Europe 2002
34
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
160
Measured without Equalizer
Measured with Equalizer
155
TVR (dB re 1uPa @ 1m)
150
145
140
135
130
125
120
115
110
180
200
220
240
260
280
300
320
340
360
Frequency (Hz)
200 Hz Multiport Measured transmitting (with and without
equalizer)
6/4/2005
UDT Europe 2002
35
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
TCR
210
TVR
TVR-TCR (dB re 1uPa @ 1m)
200
fa1=222Hz
190
fr2=333 Hz
180
Tube Coupling Coefficient
Low Frequency Tube
K=0.3
High Frequency Tube
K=0.2
170
160
fr1=212 Hz
150
fa2=324 Hz
140
130
120
110
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
Frequency (Hz)
200 Hz Multiport Measured transmitting current response
and TVR showing tube coupling coefficient
6/4/2005
UDT Europe 2002
36
SPL (dB re/1uPa @ 1m)
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
225
220
215
210
205
200
195
190
185
180
175
180
200
220
240
260
280
300
320
340
360
Frequency (Hz)
200 Hz Multiport measured at 3000 volts
6/4/2005
UDT Europe 2002
37
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
200
195
TPR (dB re 1uPa @ 1m)
190
185
180
175
170
165
160
155
150
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
Frequency (Hz)
200 Hz Multiport Measured transmitting power response
6/4/2005
UDT Europe 2002
38
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
1,400
1,200
G (uMhos)
1,000
800
600
400
200
0
180
200
220
240
260
280
300
320
Frequency (Hz)
200 Hz Multiport Conductance
340
360
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
6000
5000
4000
B (uMhos)
3000
2000
1000
0
-1000
-2000
180
200
220
240
260
280
300
320
Frequency (Hz)
200 Hz Multiport Susceptance
340
360
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Endfire
Broadside
Measured beam patterns at 200 Hz and 250 Hz
6/4/2005
UDT Europe 2002
41
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Endfire
Broadside
Measured beam patterns at 300 Hz and 350 Hz
6/4/2005
UDT Europe 2002
42
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
150
150
145
QLF=20
QLF=26
145
QHF=13
135
130
125
120
115
135
130
125
120
115
110
110
105
105
100
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
100
180
200
220
240
260
280
300
320
340
320
340
360
Frequency (Hz)
Frequency (kHz)
600 Hz Muliport TVR
200 Hz Muliport TVR
200
200
190
190
TPR (dB re 1uPa/1w @ 1m)
TPR (dB re 1uPa/1w @ 1m)
QHF=23
140
T V R (d B re 1u P a @ 1m )
TV R (dB re 1uP a @ 1m )
140
180
170
180
170
160
160
150
150
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
180
200
220
240
260
280
300
Frequency (Hz)
Frequency (kHz)
600 Hz Muliport TPR
200 Hz Muliport TPR
Measurement Summary
6/4/2005
UDT Europe 2002
43
360
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Summary
Two Low-frequency transducer operating at 200 Hz and 600 Hz
Broadband frequency range (approx. one-octave )
Free-flooded (can withstand very high pressure)
Utilizes inside and outside of piezoelectric cylinder surfaces
Measured up to 197 dB at 6.5 volts/mil (Limit 204 dB)
Measured up to 196 dB at 4 volts/mil (Limit 204 dB)
Application
Deep submergence, low-frequency, broadband acoustic source
e.g. Underwater Tomography
6/4/2005
UDT Europe 2002
44
Image Acoustics, Inc.,
97 Elm Street, Cohasset, Massachusetts 02025
Acknowledgements
This work was supported by Jan Lindberg of Office of Naval
Research through an SBIR Phase II contract.
Transducer fabrication was performed by Massa Products Corp.,
Hingham, MA, USA and Peterson Steel, Stoughton, MA, USA.
Also we would like to thank Stephen Butler of Naval Undersea
Warfare Center, Newport, RI, USA and George Cavanagh, Massa
Products for their help with transducer measurements.
6/4/2005
UDT Europe 2002
45