	US 7,600,442 B2
	Ultrasonic probing method and apparatus therefor utilizing resonance phenomenon
Masayuki Hirose, Tokyo (Japan); Masashi Kameyama, Osaka (Japan); Nobuki Dohi, Osaka (Japan); Mitsuo Okumura, Tokyo (Japan); and Hong Zhang, Tokyo (Japan)
Assigned to H&B System Co., Ltd., Tokyo (Japan); The Kansai Electric Power Co., Inc., Osaka (Japan); and Kozo Keikaku Engineering Inc., Tokyo (Japan)
Appl. No. 11/719,194 PCT Filed Nov. 16, 2004, PCT No. PCT/JP2004/016982 § 371(c)(1), (2), (4) Date Nov. 15, 2007, PCT Pub. No. WO2006/054330, PCT Pub. Date May 26, 2006.
Prior Publication US 2009/0139333 A1, Jun. 04, 2009
Int. Cl. G01N 29/12 (2006.01); G01N 29/26 (2006.01)

U.S. Cl. 73—865.8 [73/579; 73/598; 73/602; 73/606; 73/624]

20 Claims

1. An ultrasonic probing method utilizing a resonance phenomenon, by which:

a step function voltage is applied to a vibrator in a transmission probe; and

a wide band ultrasonic wave is continuously transmitted from the transmission probe and a wide band ultrasonic wave from the probing target is received by a receiving probe;

wherein a measurement is performed in the state where the transmission probe and the receiving probe are located away from each other on a surface of the probing target, the method having:

a receiving function of obtaining a received wave G_j(t) each time the position of each of the probes is changed;

an arithmetic operation function of obtaining a spectrum F_j(f) corresponding to the received wave G_j(t) by Fourier transformation;

a display function of providing a comparative display of the received wave G_j(t) and the spectrum F_j(f) at measurement points j;

a function of generating longitudinal cursors f₁, 2f₁, 3f₁, . . . , n_Af₁on a screen of the comparative display of the spectrum F_j(f), and changing the positions of the longitudinal cursors to match each of all the cursors to a rising spectrum peak having a large value;

a function of performing an arithmetic operation/display of a thickness W of the probing target from the values of the longitudinal cursors and a sonic velocity V_Pof the probing target; and

a function of obtaining a longitudinal cursor f_S1by an arithmetic operation of f_S1=γ₁·f₁using a sonic ratio γ₁between a transverse wave and a longitudinal wave of the probing target, generating longitudinal cursors f_S1, f_S2, f_S3, . . . , n_Af_S1on the screen of the comparative display of the spectrum F_j(f), and changing the positions of the longitudinal cursors by a small amount to match the cursors, which are obtained by multiplying the longitudinal cursor f_S1by an integer, to a rising spectrum peak having a relatively small value;

the method comprising:

a first step of extracting a narrow band spectrum FA_j(f) of a frequency of n_B·f_S1from the spectrum F_j(f) using an integer n_Bof 1 or greater, and obtaining a component wave GA_j(t) corresponding to the narrow band spectrum FA_j(f) by inverse Fourier transformation;

a second step of providing a comparative display of the component wave GA_j(t) using predetermined sizing coefficients n_S1, n_S2and n_S3; and

a third step of determining the position of a flaw inside the probing target right below a line segment connecting the center of the transmission probe and the center of the receiving probe, based on at which of the measurement points a wave can be confirmed to be generated on the screen of the comparative display of the component wave GA_j(t).