¥P { ¢: gå ¾ Ë 1 áS ® ot c Ü R mV R Ë ; c 6 X ¢ 1−3 ° q ¹ Š׶ ¥= k8 ý Ö «« q ¤V R Ë
Ð û B G B · ») ç « » · T ø ¶ B¦
∗Â
Ò â @ / < Æ § Ó ü t o < Æõ , Â Òí ß 608-737
*
×
<* Ö < · T ø ¶ B ¡
ô
Dz D G l > ½ ¨" é ¶ F « Ñl Õ ü t ½ ¨ è, ½ Ó" é ¶ 641-010 (2007¸ 3 Z 4 6{ 9 ~ à Î6 £ §)
· ú
[ j b _ ^ & h q 60 % 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l \ ¦ dicing-filling ~ ½ ÓZ O ` ¦ 6 x # ] j % i
. ] j ) a 1−3 · ú 4 ¤ ½ + Ë^ (f â : 25 mm, ¿ ºa : 1.25 mm)_ l x 9 6 £ § ¾ Ó: £ ¤$ í ` ¦ l 0 A
#
e x ~ Û ¼ ì r$ 3 õ ` O Û ¼-\ ï 6 £ x ² ú : £ ¤$ í \ @ /ô Ç ñK $ 3 ` ¦ Ã º' % i . 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l _
%
i < Æ& h ¾ ¡ §| 9 > Ã º (Q)ü < / B N Å Ò Ã º H y y 18.5ü < 1.6 MHz% i . Ä »o ¸[ j ' a ( ü @ â : 0.25mm, ? / â : 0.15 mm) õ r µ 1 ÏÒ q t÷ & H ò ø Í$ í \ ¦ ¿ ºa 30 mm y © ó ø Í_ © & h \ " f 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l Ð
'
a ¹ 1 Ï % i ¦, 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l _ 6 £ § ¾ Ó~ ½ ÓØ ¦ ñ H ( É Ó' Ð > í ß ) a s : r& h { 9 5 Å q ¸_ Ã ºf
$ í
ì r õ ¸ ú { 9 u % i . 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l _ 6 £ § ¾ Ó~ ½ ÓØ ¦ ñ\ ¦ Å Ò Ã º Û ¼& 7 à Ô! 3 Ü ¼ Ð ' a ¹ 1 Ïô Ç õ
, ` O Û ¼+ þ AI _ 6 £ § ¾ Ó~ ½ ÓØ ¦ ñ H ¿ ºa 1 l x ¸× ¼ Ð ç ß Å Ò ) a 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l _ 6 £ x ² ú : £ ¤$ í s ¦ F g
@
/% i _ ¨ î ò ø Íô Ç 6 £ x ² ú : £ ¤$ í ` ¦ Ð% i .
PACS numbers: 81.70.Cv
Keywords:·ú4¤½+Ë^, 6£§¾Ó~½Óئ,õ¸òøÍ$í
I. " e  ] Ø
6
£
§ ¾ Ó~ ½ ÓØ ¦ (Acoustic Emission : AE) É r ¦^ B | 9 _ ? / Â
Ò < Ê É r ³ ð \ " f # Q כ ¹ \ _ # ² D G Â Ò& h 6 £ x§ 4 © s
/ å L y o # µ 1 ÏÒ q t÷ & H ò ø Í$ í < Ê É r 8 £ ¤& ñ > \ ¦ í
< Êô Ç ' aº & ³ © ` ¦ : xg A # ´ ú ô Ç [1]. s Qô Ç AE8 £ ¤& ñ
>
H l : r& h Ü ¼ Ð (1) AEµ 1 ÏÒ q t" é ¶, (2) B | 9 , (3) AE
¨ 8
l x 9 (4) ñK $ 3 r Û ¼% 7 Ü ¼ Ð Ð ü t à º e . Å Ò Ð z ´ +
« >z ´õ í ß \ O & ³ © \ " f H ñK $ 3 r Û ¼% 7 \ " f % 3 # Q & ñ
Ð Ð" f AEµ 1 ÏÒ q t" é ¶ _ : £ ¤$ í ` ¦ Æ Ò : r ¦ e Ü ¼ , z ´] j Ð ' a
¹
1 Ï ) a AE ñ Ð" f AE\ ¦ & ñ S X y H X < ´ ú § É r # Q 9¹ ¡ § s
É r .
&
³F AE H ´ ú § É r ë H ] j& h s e 6 £ § \ ¸ Ô ¦ ½ ¨ ¦ @ /+ þ A½ ¨
¸Ó ü t õ " é ¶ § 4 í ß \ O õ ° ú É r l ç ß í ß \ O _ î ß $ í S X Ð H 8
£ ¤ \ " f 9 כ ¹ . : £ ¤ y , AEµ 1 ÏÒ q t" é ¶ \ @ /ô Ç & ñ S X ô Ç 6 £ § ¾ Ó :
£ ¤$ í ` ¦ ½ ¨ l 0 AK V , É r Å Ò Ã º @ /% i \ " f =/ B G s \ O
H ò ø Í$ í + þ A` ¦ Ã º ½ + É Ã º e H í6 £ § ¨ 8 l \ @ /ô Ç
½ ¨ 9 כ ¹ . z ´] j Ð AE\ " f H \ -t ¨ 8 ´ òÖ ¦ õ S/N q ß ¼ 9 [ O u ç ß ¼ # ô Ç / B N + þ A PZT[ j b ¨ 8
∗E-mail: [email protected]
l
\ ¦ Å Ò Ð 6 x ÷ & ¦ e Ü ¼ , PZT[ j b ¨ 8 l H Å Ò Ã
º@ /% i s V , t · ú § . Å Ò Ã º @ /% i s V , ¦ ³ ð 0 A\ q Y
V H Y Us $ ç ß [ O > [2], 6 x | ¾ Ó+ þ A ¨ 8 l [3], " é ¶ Æ Ò+ þ A
¨ 8
l [4, 5] 1 p x _ F g @ /% i ¨ 8 l > hµ 1 Ï÷ &# Q 6 x ¦ e t
ë ß , s Qô Ç F g @ /% i ¨ 8 l H z ´+ « > ¸| s -Á º Ð 0
>" f z ´+ « >z ´\ " fë ß 6 x ÷ & ¦ í ß \ O & ³ © \ & h 6 x l j Ë µ[ þ t
.
PZT [ j b ¨ 8 l H 150 kHz\ " f 2 MHz % ò % i _ Å
Ò Ã º @ /% i \ " f 6 x ÷ & ¦ e . s Å Ò Ã º@ /% i _ PZT [
j b ¨ 8 l H ¿ ºa 1 l x ¸× ¼ (thickness mode) ü @\ ¸ 1
l x â ~ ½ Ó ¾ Ó_ 1 l x ¸× ¼ (radial mode) 1 p x s ½ + Ë÷ &# Q4 R ò ø Í
$ í
\ @ /ô Ç 6 £ x ² ú ` ¦ =/ B G r v ¦ e . \ O ¨ 8 â _ 9 כ ¹
\
" f AE ¨ 8 l 9 כ ¹ ¦, s ¨ 8 l H { 9 H ò
ø Í$ í \ @ / # ¿ ºa 1 l x ¸× ¼, 1 l x â ~ ½ Ó ¾ Ó 1 l x ¸× ¼, l
# Q É r ¸× ¼ 1 p x s í6 £ § ñ\ ¦ =/ B G r
.
þ
j H \ > hµ 1 Ï ) a 1−3 · ú 4 ¤ ½ + Ë^ [6–8]ü < PZT[ j b
¨ 8
l \ ¦ q § , 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l H PZT [ j b
¨ 8 l Ð Å Ò Ã º @ /% i s V , ¦, l 6 £ § ¾ Ó ¨ 8 ´ òÖ ¦ s Z
} Ü ¼ 9, 1 l x â ~ ½ Ó ¾ Ó ¸× ¼ Ð ¿ ºa ~ ½ Ó ¾ Ó ¸× ¼\ @ /ô Ç _ > r$ í s
ß ¼ ¦ · ú 94 R e . z ´] j Ð 1−3 · ú 4 ¤ ½ + Ë^ \ ¦ ¨ 8
-368-
Fig. 1. Dimension of the 1−3 piezoelectric composite.
Fig. 2. Block diagram of the AE system during glass capillary breakage.
l
Ð ] j ½ + É â Ä º\ ] j õ & ñ \ " f ´ ú § É r # Q 9¹ ¡ § s e 6 £ §
\
¸ Ô ¦ ½ ¨ ¦ 0 A\ " f / å L ) a © & h M :ë H \ à º× æ' õ A6 £ § l ü <
í6 £ § Ã Ð © 6 x ¨ 8 l Ð > hµ 1 Ï ¦ e .
: r 7 Hë H \ " f H 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l AE ¨ 8 l
Ð" f 6 x 0 p x$ í ` ¦ ¸ % i . · ú [ j b _ ^ & h q
60 % 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l \ ¦ dicing-filling ~ ½ ÓZ O
`
¦ 6 x # ] j # 1−3 · ú 4 ¤ ½ + Ë^ _ l : £ ¤$ í x 9 6 £ §
¾ Ó: £ ¤$ í ` ¦ ¸ % i . Ä »o ¸[ j ' a õ r µ 1 ÏÒ q t÷ & H ò ø Í$ í
\ ¦ ¿ ºa 30 mm y © ó ø Í_ © & h \ " f ] j ) a 1−3 · ú
4 ¤ ½ + Ë^ ¨ 8 l \ ¦ 6 x # 8 £ ¤& ñ x 9 ì r$ 3 % i .
II. ÷ m Ç] M öU ê s0 n É
1−3 · ú 4 ¤ ½ + Ë^ H ì rF G ) a PZT · ú [ j b (PZT-5A)
`
¦ ] X é ß © q \ ¦ 6 x # Fig. 1õ ° ú s kerf 80 µm, pitch 350 µm ÷ & ¸2 ¤ dicing % i . dicing ) a · ú [ j b \ e
¦ o Q\ ¦ G Ä º ¦, 60
◦C & ñ ¸\ " f 4r ç ß 1 l x î ß â or (
. â o ) a 1−3 · ú 4 ¤ ½ + Ë^ _ ¿ ºa H 1.25 mm s ¦ ³ ð
Ê ê Cu-Ni F G` ¦ ë ß [ þ t% 3 .
¨ 8 l _ ü @Â Ò H · ú À Òp ³ o u, Ê ê F H / B N l 8 £ x Ü ¼ Ð
%
i ¦ F H 1−3 · ú 4 ¤ ½ + Ë^ \ 6 x ) a e ¦ o Q Ð" f 0.2 mm ¿ ºa Ð ] j % i . ] j ) a 1−3 · ú 4 ¤ ½ + Ë^
¨ 8
l _ Ó ü t o & h : £ ¤$ í ` ¦ Table 1 \ ? /% 3 . ] j ) a
¨ 8
l _ l : £ ¤$ í ` ¦ l 0 AK IEEE ³ ðï r \ " f ] jr
)
a ~ ½ ÓZ O Ü ¼ Ð / B N Å Ò Ã º Â Ò H \ " f e x ~ Û ¼\ ¦ 8 £ ¤& ñ % i
¦ [9], 6 £ § ¾ Ó: £ ¤$ í É r ` O Û ¼−\ ïZ O ` ¦ 6 x # 8 £ ¤& ñ % i
.
Table 1. Specification of the 1−3 piezoelectric composite.
Diameter(D) (mm) 25 Thickness(T) (mm) 1.25
T / D of PZT 0.05 Volume fraction (%) 60
Ä
»o ¸[ j ' a õ r AEr Û ¼% 7 \ @ /ô Ç ½ ¨$ í ¸\ ¦ Fig.
2 \ ? /% 3 . Ä »o ¸[ j ' a õ \ ¦ 0 Aô Ç indentor H Tungsten Carbide (WC)4 x õ load cell Ð ½ ¨$ í ÷ &# Q e .
WC4 x É r B | 9 y © ó ø Íõ ¨ î ' s ¦ Ä »o ¸[ j ' a õ Ã º f
> 0 Au ¦ e . 6 x ) a Ä »o ¸[ j ' a É r ? / â 0.15 mm, ü @ â 0.25 mms ¦ y © ó ø Í_ ¿ ºa H 30 mm% i . Ä »o
¸[ j ' a õ r µ 1 ÏÒ q t ) a õ ¸ò ø Í$ í y © ó ø Í ? /Â Ò Ð
> ÷ & ¦, © & h \ " f 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l Ð" f AE
\
¦ 8 £ ¤& ñ % i . y © ó ø Í_ 7 á x ü < S 5 Å q ¸ H y y 5,930 m/s ü < 3,240 m/s% i .
III. + s ÇÊ Ý õ m Í Ä Z ØV Ä
1. 1−3 ° q ¹ Š׶ ¥= k ì Åò & ÿM 8 ý ¹ ÅM ¤V R Ë õ m Í Ö ¨] §
¤V R Ë
1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l \ @ / # e x ~ Û ¼ ì r$ 3 #
%
3 # Q ¨ 8 l _ Ó ü t o & h © Ã º H IEEE ³ ðï r \ " f ] jî ß ) a
~
½ ÓZ O \ ½ ¨ % i ¦, õ H Table 2 \ ? /% 3 .
1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l _ Ó ü t o & h © à ºü < s : r ° ú כ` ¦ q §
ç ß _ s e 6 £ §` ¦ · ú Ã º e ¦, s כ É r s : r& h
> í ß \ " f H l : r& h Ü ¼ Ð · ú [ j b õ e ¦ o Q_ ¢ - a# 4 ô
Ç ½ + Ë, ¿ ºa ~ ½ Ó ¾ Ó 1 l x Å Ò Ã º É r 1 l x Å Ò Ã ºü < & ñ
½
+ Ës { 9 # Q t · ú § H H & ñ ` ¦ % i ¦, 1−3 · ú 4 ¤ ½ + Ë
^
\ " f { 9 # Q± ú à º e H % i < Æ& h , · ú & h < Hz ´ 1 p x` ¦ ¸¿ º Á
ºr % i l M :ë H s .
{ 9
ì ø Í& h PZT· ú [ j b _ % i < Æ& h ¾ ¡ §| 9 > Ã º (Q) H 50
∼ 1,000 _ ° ú כ` ¦ ? / ¦, : x õ @ /% i ; ¤ s a % v É r ¨ 8 l H ]
j ½ + É Ã º e Ü ¼ F g @ /% i _ ¨ 8 l Ð ] j l H j Ë µ[ þ t
Fig. 3. (a) Theoretical normal particle velocity and ob- served AE signal(load (b) 12.1 N (c) 16.2 N (d) 19.0 N) of the 1−3 piezoelectric composite transducer.
Fig. 4. Frequency spectrum of the 1−3 piezoelectric com- posite transducer..
[10]. ] j ) a 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l \ @ /ô Ç % i < Æ& h
¾
¡ §| 9 > Ã º (Q) H 18.5 Ð z ¤ .
Fig. 5 É r ` O Û ¼-\ ïZ O \ _ K Ã º ) a ` O Û ¼6 £ x ² ú x 9 Å Ò
à º Û ¼& 7 à Ô! 3 ` ¦ · p כ s . Å Ò Ã º Û ¼& 7 à Ô! 3 ` ¦ Ð
, ¨ 8 l _ / B N Å Ò Ã º H 1.6 MHz Ð z ¤ ¦, ¿ ºa
~
½ Ó ¾ Ó l : r 1 l x Å Ò Ã º_ 6 £ § ¾ Ó\ -t ¿ ºa ~ ½ Ó ¾ Ó l : r 1
l
x Å Ò Ã º_ 3C ÷ & H 1 l x Å Ò Ã º_ 6 £ § ¾ Ó\ -t Ð Z 4 1
p
x y ß ¼l M :ë H \ ¿ ºa ~ ½ Ó ¾ Ó 1 l x \ @ /ô Ç _ > r$ í s ß ¼
Table 2. Electrical characteristics of the 1−3 piezoelec- tric composite transducer.
E 0.58
k
tT 0.64
E 6.71
c
E33[10
10N/m
2]
T 4.25
E 10.11
c
D33[10
10N/m
2]
T 7.19
E 355.8
ε
S33/ε
0T 517.6
E 10.4
e
33[C/m
2]
T 11.6
Z [kg/m
2s] 22.5
C
0+ C1 [nF] 1.7
Q 18.5
E : Measurement data
T : Manufacturer and theoretically calculated data
Fig. 5. (a) Pulse-echo signal and (b) its frequency spec- trum of the 1−3 piezoelectric composite transducer.
¦ K $ 3 ½ + É Ã º e .
2. 1−3 ° q ¹ Š׶ ¥= k ì Åò & ÿM 8 ý Ê Ýy ¢ Ö «« q ¤V R Ë
Fig. 3(a) H © 5 p x r ç ß s 300 nss ¦ 1 N ß ¼l > é ß
< ÊÃ º + þ AI _ j Ë µ\ _ # µ 1 ÏÒ q t ) a ò ø Í$ í \ ¦ © & h \ " f (
É Ó' Ð > í ß ) a s : r& h { 9 5 Å q ¸_ Ã ºf $ í ì r` ¦
?
/ ¦, Ä »o ¸[ j ' a _ õ r ) a j Ë µ_ ß ¼l \
¨ 8
l \ Ã º ) a AE ñ\ ¦ Fig. 3(b) ∼ 3(d) \ ? /% 3
.
1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l Ð ' a ¹ 1 Ï ) a z ´+ « > AE ñ_ 1P, 3P ü < 5P_ ¸² ú r ç ß É r y y 5.09 µs, 14.19 µsü < 15.19 µs s ¦, s : r ñü < ¸ ú { 9 u < Ê` ¦ · ú à º e . Ä »o ¸[ j
'
a õ r ) a j Ë µ_ ß ¼l 7 £ x ¨ 8 l \ Ã º
)
a ; ¤ _ ß ¼l ¸ 7 £ x ¦, 1P, 3P x 9 5P\ @ /6 £ x H AE
ñ_ ; ¤ É r > h| Ä Ì& h Ü ¼ Ð ½ ¨ ü < ° ú s o ] jY L \ ì
ø Íq Y Vô Ç . AE ñ\ " f 1P, 3Pü < 5P\ @ /6 £ x ÷ & H 1−3
· ú
4 ¤ ½ + Ë^ ¨ 8 l \ { 9 H { 9 5 Å q ¸_ Ã ºf $ í ì r \ _
> r ¦, s Ð p À Ò# Q ^ ¦ M : 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l H
¿
ºa ~ ½ Ó ¾ Ó 1 l x ¸× ¼\ ß ¼> _ > r < Ê` ¦ · ú à º e .
¸ 1 p x [11] \ " f ' a ¹ 1 Ï ) a PZT · ú ¨ 8 l \ " f H ring- ing` ¦ ? /t ë ß 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l \ " f H ring- ing s t · ú § ¤ . 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l \ H G 0
> e ¦ o QM :ë H \ ò ø Í$ í y û Z p u Ü ¼ Ð ringings
t · ú § H ¦ Ò q ty ô Ç .
Fig. 4 H 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l _ Å Ò Ã º Û ¼& 7 à Ô! 3
`
¦ · p כ s . 0.5 MHz ∼ 1.5 MHz % ò % i \ " f ¨ î ò ø Íô Ç 6
£
x ² ú : £ ¤$ í ` ¦ f ` ¦ · ú Ã º e .
IV. + s Ç Â ] Ø
· ú
[ j b _ ^ & h q 60 % 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l
(f â : 25 mm, ¿ ºa : 1.25 mm)\ ¦ dicing-filling ~ ½ ÓZ O ` ¦
6 x # ] j % i . 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l _ % i < Æ& h
¾
¡ §| 9 > Ã º (Q)ü < / B N Å Ò Ã º H y y 18.5ü < 1.6 MHz% i
. Ä »o ¸[ j ' a õ r õ ¸ò ø Í$ í \ @ /ô Ç 1−3 · ú 4 ¤
½
+ Ë^ ¨ 8 l _ 6 £ x ² ú : £ ¤$ í É r { 9 ) a { 9 5 Å q ¸_ Ã ºf $ í ì r õ
¸ ú { 9 u % i . 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l _ AE ñ\ ¦
Å
Ò Ã º Û ¼& 7 à Ô! 3 Ü ¼ Ð ' a ¹ 1 Ïô Ç õ , ` O Û ¼+ þ AI _ AE ñ
H ¿ ºa 1 l x ¸× ¼ Ð ç ß Å Ò ) a 1−3 · ú 4 ¤ ½ + Ë^ ¨ 8 l _ 6 £ x
² ú
: £ ¤$ í s ¦ 0.5 MHz ∼ 1.5 MHz % ò % i \ " f ¨ î ò ø Íô Ç 6 £ x ² ú :
£ ¤$ í ` ¦ f ` ¦ · ú Ã º e % 3 .
Y
c p w à U Ø ô
[1] R. W. B. Stephens and H. C. Kim, Ultrasonic Test- ing (John Wiley & Sons LTd., 1982), p. 459.
[2] R. A. Kline, R. E. Green and C. H. Palmer, J.
Acoust. Soc. Am. 64, 1633 (1978).
[3] A. N. Ceranoglu and Y. H. Pao, J. Appl. Mech. 48, 125 (1981).
[4] Y. H. Kim, D. J. Yoon, S. K. Lee and H. C. Kim, Korean Applied Physics 3, 374 (1990).
[5] Thomas M. Proctor, Jr. J. Acoust. Soc. Am. 71, 1163 (1982).
[6] R. Y. Ting and T. R. Howarth, Proc. Int’l, Soc. for Optical Eng. SPIE 3044, 158 (1997).
[7] J. G. Wan and B. Q. Tao, Materials and Design 21, 533 (2000).
[8] R. Marat-Mendes, C. J. Dias and N. Marat-Mendes, Sensorrs and Actuators 76, 310 (1999).
[9] IEEE Standard on Piezoeletricity, IEEE Std 176 (2002).
[10] H. J. McSkimin and W. P. Mason, Physical Acous- tics, (Academic Press, New York, 1964), P. 271.
[11] S. I. Cho, J. K. Lee, D. H. Lee and S. S. Jung,
SAEMULLI (New Phys.) 45, 320 (2002).
Response of a 1−3 Piezoelectric Composite Transducer to Elastic Waves Generated During Glass Capillary Breakage
Seung Il Cho, Sung Boo Kim and Jong Kyu Lee
Department of Physics, Pukyong National University, Pusan 608-737
Woon Ha Yoon and Jong O Lee
Materials Research Institute, Korea Institute of Machinery & Materials, Changwon 641-010 (Received 6 March 2007)
A 1−3 piezoelectric composite transducer with a 60 % volume fraction of PZT-5A was fabricated by using the dicing-filling method. The electrical and the acoustical characteristics of the 1−3 piezoelectric composite transducer were analyzed by using electrical impedance measurements and the pulse-echo method. The mechanical quality coefficient (Q) and the resonant frequency were 18.5 and 1.6 MHz, respectively. Elastic waves generated during glass capillary breakage were observed by using the 1−3 piezoelectric composite transducer. The observed AE signals matched well with the perpendicular component of the particle velocity calculated by computer. The observed AE signal and its frequency spectrum showed that the pulse-type AE signals observed by using the 1−3 piezoelectric composite transducer might depend on the vibration mode of thickness with the plate response of the wide band.
PACS numbers: 81.70.Cv
Keywords: Piezoelectric composite, Acoustic emission, Elastic wave
![Fig. 2. Block diagram of the AE system during glass capillary breakage. l Ð ] j ½+ É â Ä º\ ] j õ &ñ \ " f ´ú §Ér # Q 9¹¡§ s e 6£§ \ ¸ Ô ¦ ½ ¨
¦ 0 A\ " f /å L)a © &h M :ëH \ à º× æ'õ A6£§ l ü< ](https://thumb-ap.123doks.com/thumbv2/123dokinfo/5435309.232838/2.892.465.833.379.467/fig-block-diagram-ae-glass-capillary-breakage-ér.webp)
![Fig. 4. Frequency spectrum of the 1−3 piezoelectric com- com-posite transducer.. [10]](https://thumb-ap.123doks.com/thumbv2/123dokinfo/5435309.232838/3.892.463.830.201.461/fig-frequency-spectrum-piezoelectric-com-com-posite-transducer.webp)
