ULTRASONIC TESTING SENSOR AND ULTRASONIC TESTING METHOD

• US 20150122029A1
• Filed: 11/03/2014
• Published: 05/07/2015
• Est. Priority Date: 11/07/2013
• Status: Active Grant

• Current Assignee: Mitsubishi Power Limited (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: mitsubishi hitachi power systems, ltd. (Mitsubishi Heavy Industries, Ltd.)
• Inventors: SUZUKI, Yutaka, CHIBA, Hiroaki, KUDO, Takeshi
• Granted Patent: US 9,435,769 B2
• Time in Patent Office: Days
• US Class Current: 73/620
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/102 one emitter, one receiver
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 29/043 in the interior, e.g. by shear waves
• CPC Class Codes: G01N 29/221 Arrangements for directing or focusing the acoustical waves electronic orientation or focusing G01N29/262; sound directing or focusing G10K11/26; mechanical steering of sound transducers or their beams G10K11/35
• CPC Class Codes: G01N 29/262 by electronic orientation or focusing, e.g. with phased arrays phased arrays per se G10K11/34
• CPC Class Codes: G01N 29/265 by moving the sensor relative to a stationary material

Abstract

The transmission sensor 1T and the reception sensor 1R are disposed so as to sandwich a testing target 301 therebetween. The reception sensor 1R receives a false signal arising from a GL generated upon ML scanning by a scanning angle equal to or greater than a minimum scanning angle Φmin but equal to or smaller than a maximum scanning angle Φmax.

Claims

1. An ultrasonic testing sensor, comprising:

a transmission sensor configured from ultrasonic elements of a parallelepiped arrayed one-dimensionally, the transmission sensor transmitting ultrasonic waves whose center frequency has a wavelength λ

; and

a reception sensor configured from ultrasonic elements of a parallelepiped arrayed one-dimensionally, the reception sensor receiving reflected waves of the ultrasonic waves, wherein

the reception sensor receives a grating lobe in accordance with a main lobe, the grating lobe being reflected within a testing range scanned by the main lobe having a scanning angle equal to or greater than a minimum scanning angle Φ

min but equal to or smaller than a maximum scanning angle Φ

max.

2. The ultrasonic testing sensor according to claim 1, wherein a testing target width W indicative of a width of the testing target, a length L0 of the transmission sensor necessary for flaw detection, a generation angle Δ

φ

indicative of an angle of the grating lobe with respect to the main lobe and a length Lr of the reception sensor satisfy

Lr≧

W{tan(Φ

max+Δ

φ

)−

tan(Φ

min−

Δ

φ

)}+L0

and

the transmission sensor has an element pitch equal to or greater than λ

/2.

3. The ultrasonic testing sensor according to claim 1, wherein a distance h1 between a testing position and a minimum scanning angle outgoing center position, a minimum distance W1 from a transmission sensor installation position to the testing position and a minimum length L1 of the transmission sensor satisfy

Lr=h1−

W1·

tan(Φ

max)+L0

and an element pitch d is equal to or smaller than λ

/2 within a range of ±

L0/2 from the minimum scanning angle outgoing center position while the element pitch in the other range than the range of ±

L0/2 is equal to or greater than λ

/2 and a maximum scanning angle is 55 degrees.

4. An ultrasonic testing method, comprising the steps of:

calculating a generation angle Δ

φ

a grating lobe;

evaluating, on the basis of a shape of a testing target and positions of a transmission sensor and a reception sensor with respect to the testing target, whether there exists a reflection source in a grating lobe generation direction;

measuring a reception position of a reflected wave by the reception sensor; and

comparing the reception position of the grating lobe based on the calculated generation angle Δ

φ and

the measured reception position of the reflected wave with each other to evaluate whether the reflected wave is a reflected wave of the grating lobe.

5. The ultrasonic testing method according to claim 4, further comprising the steps of:

transmitting a main lobe in the grating lobe generation direction; and

determining, when a reflected wave by the main lobe is measured at the reception position of the grating lobe based on the calculated generation angle Δ

φ

, that the reflected wave is noise by the grating lobe.