IEEE IUS 2012 - Visualization of lamb wave propagation in uncured CFRP
1
M.D. Fariñas, H. Calás and Tomás E. Gómez Álvarez-Arenas UMEDIA, CSIC, Serrano 144, 28006, Madrid, Spain Experimental Results I. Uncured CFRP composite Propagation of Lamb waves, generated and detected using air-coupled piezoelectric transducers in the frequency range 0.1-1.0 MHz, is visualized. Hence phase and group velocities are obtained. The technique has initially been applied to plates (first aluminum plates and then to cured and uncured carbon fiber reinforced polymers –CFRP-). Then it has been applied to curved surfaces: steel pipes and vessels and to the curved section of CFRP beams. Two different experimental set-ups are proposed: 1) use of monolithic transducers and mechanical scans along the direction of propagation, 2) use of a phased array linear transducer and an electronic scan along the direction of propagation. VISUALIZATION OF LAMB WAVE PROPAGATION IN UNCURED CFRP AND CURVED SURFACES USING AIR-COUPLED ULTRASOUND Lamb Wave Velocity in Aluminum Plate at 250 kHz 0.9 1 1.1 1.2 1.3 1.4 1.5 x 10 -4 time [s] Group Velocity Phase Velocity Lamb Wave Velocity in Cured CFRP at 650 kHz Cured CFRP • A method to visualize Lamb wave propagation in plates and shells and hence to simultaneously determine phase and group velocities has been proposed. • The method has first been tested with aluminum and CFRP plates. Results are compared with theoretically calculated dispersion relations • Then it has been applied to the study of A 0 Lamb wave mode in uncured CFRP composites. Though relatively lower velocities and higher attenuation coefficients compared with cured CFRP have been obtained, it is still possible to observe Lamb waves in uncured CFRP. • Finally, the method has been applied to generate and sense axial and circumferential Lamb waves in steel pipes and vessels, and to CFRP beams developed for civil engineering applications. Axial Lamb Wave in a Steel Pipe at 250 kHz 0 0.5 1 1.5 2 2.5 3 3.5 x 10 -4 time [s] Circunferential Lamb Waves in a cylindrical Reactor at 250 kHz Materials and Methods. Visualization of phase and group velocities of Lamb waves in plates. Mechanical Y-SCAN Electronic Scan (Air-Coupled Phase Array ) Foam CFRP Lamb Wave in a Beam of CFRP laminates and sandwich structure (CFRP-foam) at 250 kHz 0.8 1 1.2 1.4 1.6 1.8 2 x 10 -4 time [s] Y-SCAN total scan distance= 77.5 mm step=0,5 mm 6 7 8 9 10 11 12 13 x 10 -5 time [s] Y-SCAN total scan distance= 129,5 mm step=0,5 mm Y-SCAN total scan distance= 129,5 mm step=0,5 mm Y-SCAN total scan distance= 32 mm step=4 mm 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 x 10 -4 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 Time (s) 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 x 10 -4 15 10 -5 0 Time (s) Y-SCAN total scan distance= 25 mm step=5 mm Y-SCAN total scan distance= 45 mm step=5 mm Amplitude (V) Amplitude (V) Lamb Wave n Uncured CFRP plate (1.1 mm) at 250 kHz Lamb Wave in Cured CFRP plate (2.1 mm) at 250 kHz 1 2 3 x 10 -4 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 time [s] 900 V, 60 dB 1 2 3 x 10 -4 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 time [s] 900 V, 40 dB Amplitude (V) Amplitude (V) 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 x 10 -4 time [s] Lamb Wave Velocity in Aluminum Plate at 750 kHz ELECTRONIC SCAN Array 30 elements pitch=2mm aperture=5 elements Lamb Wave in Uncured CFRP plate (5mm) at 250 kHz Lamb Wave in cured CFRP plate (5 mm) at 250 kHz Experimental Results II. Curved surfaces, axial and circunferential Lamb waves https://sites.google.com/site/umediaresearchgroup/IUS-2012 [email protected] [email protected] 1 2 3 Hilbert Transform of Lamb Wave in Aluminum at 250 kHz 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 x 10 -4 Time [s] Experimental CFRP Data over Theoretical Curves Experimental Aluminum Data over Theoretical Curves
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Transcript of IEEE IUS 2012 - Visualization of lamb wave propagation in uncured CFRP
M.D. Fariñas, H. Calás and Tomás E. Gómez Álvarez-Arenas
UMEDIA, CSIC, Serrano 144, 28006, Madrid, Spain
Experimental Results I. Uncured CFRP composite
Transmission coefficient in Epipremnun aureum leaf versus frequency at incidence angle of
30º during dehydratation
Propagation of Lamb waves, generated and detected using air-coupled piezoelectric transducers in the frequency range 0.1-1.0 MHz, is visualized. Hence phase and group velocities are
obtained. The technique has initially been applied to plates (first aluminum plates and then to cured and uncured carbon fiber reinforced polymers –CFRP-). Then it has been applied to curved
surfaces: steel pipes and vessels and to the curved section of CFRP beams. Two different experimental set-ups are proposed: 1) use of monolithic transducers and mechanical scans along
the direction of propagation, 2) use of a phased array linear transducer and an electronic scan along the direction of propagation.
VISUALIZATION OF LAMB WAVE PROPAGATION IN UNCURED CFRP
AND CURVED SURFACES USING AIR-COUPLED ULTRASOUND
50 55 60 65 70 75 80 85 90 95100
110
120
130
140
150
160
170
Transducers separation (mm)
Tim
e d
ela
y (
mic
ros)
Uncured plate
v=943 m/s
Cured plate
v=1480 m/s
Lamb Wave Velocity in Aluminum Plate
at 250 kHz
0.9 1 1.1 1.2 1.3 1.4 1.5
x 10-4time [s]
Group Velocity
Phase Velocity
Lamb Wave Velocity in Cured CFRP
at 650 kHz
Aluminum Plate Cured CFRP
• A method to visualize Lamb wave propagation in plates and shells and hence to simultaneously determine phase and group velocities has
been proposed.
• The method has first been tested with aluminum and CFRP plates. Results are compared with theoretically calculated dispersion relations
• Then it has been applied to the study of A0 Lamb wave mode in uncured CFRP composites. Though relatively lower velocities and higher
attenuation coefficients compared with cured CFRP have been obtained, it is still possible to observe Lamb waves in uncured CFRP.
• Finally, the method has been applied to generate and sense axial and circumferential Lamb waves in steel pipes and vessels, and to CFRP
beams developed for civil engineering applications.
Axial Lamb Wave in a Steel Pipe at
250 kHz
0 0.5 1 1.5 2 2.5 3 3.5
x 10-4time [s]
Circunferential Lamb Waves in
a cylindrical Reactor at 250 kHz
Materials and Methods. Visualization of phase and
group velocities of Lamb waves in plates.
Mechanical Y-SCAN Electronic Scan (Air-Coupled Phase Array )
Foam CFRP
Lamb Wave in a Beam of CFRP laminates and
sandwich structure (CFRP-foam) at 250 kHz
0.8 1 1.2 1.4 1.6 1.8 2
x 10-4time [s]
Y-S
CA
N t
ota
l scan
dis
tan
ce
= 7
7.5
mm
s
tep
=0,5
mm
6 7 8 9 10 11 12 13
x 10-5time [s]
Y-S
CA
N t
ota
l scan
dis
tan
ce
= 1
29
,5 m
m s
tep
=0,5
mm
Y
-SC
AN
to
tal scan
dis
tan
ce
= 1
29
,5 m
m s
tep
=0,5
mm
Y-S
CA
N t
ota
l scan
dis
tan
ce
= 3
2 m
m s
tep
=4 m
m
0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
x 10-4
-4
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
Time (s)
Ampl
itude
(V)
Uncured FRP plate
0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
x 10-4
-15
-10
-5
0
Time (s)
Ampli
tude (
V)
Cured FRP plate
Y-S
CA
N to
tal s
can
dis
tan
ce
= 2
5 m
m s
tep
=5 m
m
Y-S
CA
N to
tal s
can
dis
tan
ce
= 4
5 m
m s
tep
=5 m
m
Am
plitu
de
(V
) A
mp
litu
de
(V
)
Lamb Wave n Uncured CFRP plate (1.1 mm) at 250 kHz
Lamb Wave in Cured CFRP plate (2.1 mm) at 250 kHz
1 2 3
x 10-4
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
time [s]
900 V, 60 dB
1 2 3
x 10-4
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
time [s]
900 V, 40 dB
Am
pli
tud
e (
V)
Am
pli
tud
e (
V)
1.5 1.6 1.7 1.8 1.9 2 2.1 2.2
x 10-4time [s]
Lamb Wave Velocity in Aluminum Plate
at 750 kHz
EL
EC
TR
ON
IC S
CA
N A
rra
y 3
0 e
lem
en
ts p
itc
h=
2m
m a
pe
rtu
re=
5 e
lem
en
ts
Lamb Wave in Uncured CFRP plate (5mm) at 250 kHz
Lamb Wave in cured CFRP plate (5 mm) at 250 kHz
Experimental Results II. Curved surfaces, axial and circunferential Lamb waves
https://sites.google.com/site/umediaresearchgroup/IUS-2012
[email protected] [email protected]
1 2
3
Hilbert Transform of Lamb Wave in
Aluminum at 250 kHz
0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
x 10-4Time [s]
Experimental CFRP Data over
Theoretical Curves
Experimental Aluminum Data over
Theoretical Curves
