JPH02129544A - Ultrasonic flaw detecting device - Google Patents

Abstract

PURPOSE:To supervise the phase variation of the waveform of an ultrasonic wave reflected at each probe position visually by storing the reflection waveform of the ultrasonic wave from the adhesion surface in a sample which is detected by an ultrasonic wave probe together with position information on the probe. CONSTITUTION:The ultrasonic wave received signal from the sample 3 which is received by an ultrasonic wave transmitter receiver 1 through the ultrasonic wave probe 2 is supplied to a high-speed A/D converter 5 and converted into a digital waveform signal, which is stored in a digital memory 6 together with the probe position information of a position detector 4 for the probe 2. Then the ultrasonic wave data stored in the memory 6 is processed by a signal processor 7 and supplied to a display recorder 8 to display its image. Thus, the phase variation of the reflection waveform from the adhesive surface in the sample can be displayed visually to easily inspect a peeling state with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an ultrasonic flaw detection device that uses ultrasonic waves to inspect peeling conditions on adhesive surfaces of metallic materials, non-metallic materials, and the like.

(Prior Art) Conventionally, in the case of structural members etc. in which metal and plastic or metals of different materials are bonded together, an ultrasonic peel inspection has been carried out to ensure the quality of the bonded surfaces of these members.

By the way, when dissimilar materials are bonded together, there is a relatively large difference in acoustic impedance between the two materials, so even if the bonding is secure, ultrasonic waves may be reflected at the bonded surfaces. be. This means that determining the peeling situation on the adhesive surface only based on the echo height from the adhesive surface would lead to extremely inaccurate results, and therefore could only be applied to a limited number of applications.

Therefore, conventional peeling detection methods have been considered that rely not only on the echo height of the adhesive surface but also on the phase change of the adhesive surface echo due to the difference in acoustic impedance.

This change in phase due to acoustic impedance is, for example,
It is explained in detail on pages 21 to 23 of ``Ultrasonic Testing Technology (Theory and Practice)'' edited by the Japan Management Association.

In other words, if the sound pressure of an ultrasound that is perpendicularly incident on the boundary between a medium 1 with an acoustic impedance Zl and a medium 2 with an acoustic impedance Z2 is Pe and the reflected sound pressure is Pr, then the reflectance of the ultrasound at the interface is is R-Pr/Pe, and the relationship with acoustic impedance is expressed as 22-2°Z2+21.

Here, when Z>22, R becomes a negative value and the phase of the reflected wave is opposite to that of the incident wave.

From this, it can be seen that if ultrasonic waves are incident on the above-mentioned contacting surfaces from a direction such that Z1 minus Z2, the reflected waves will have the same phase as the incident waves when the bond is secure, but if In the case of plagiarism, the boundary is in contact with the air, so the acoustic impedance has a relationship of Zl>22 due to the influence of the air layer, which is close to 0, and the reflected wave has an opposite phase to the incident wave. Therefore, peeling can be detected by utilizing changes in this relationship.

(Problem to be solved by the invention) By the way, whether the phase of the reflected wave is in the same phase as the incident wave can be determined from the comparison result with the incident wave, but what can actually be observed is the shape of the reflected wave. Therefore, it is necessary to make a judgment by indirectly comparing the reflected waveform when the adhesive is firmly adhered and the reflected waveform during peeling.

This requires the operator to be familiar with the phase changes of the waveforms in the adhesion state and in the peeling state.

Moreover, in this case, the judgment is made based on the rising direction of the waveform and the symmetry of the positive and negative sides of the waveform, so it is easily influenced by the subjectivity of the operator, and when the reflected waveform is disturbed, etc. There is a problem that the characteristics may become unclear, leading to incorrect judgments.

The present invention has been made in view of the above-mentioned circumstances, and provides an ultrasonic flaw detection device that can visually display the phase change of the reflected waveform from the adhesive surface of the object and that can easily and highly accurately inspect the peeling situation. The purpose is to

[Structure of the invention] (Means for solving the problem) The present invention uses ultrasonic waves from the adhesive surface inside the object detected by an ultrasonic probe that scans the surface of the object made by bonding different materials. The reflected waveform is stored as an RF waveform together with the position information of the probe, and the ultrasonic RF waveform is stored on a two-dimensional coordinate system based on the ultrasonic probe position and the ultrasound propagation time axis. The image is displayed using color gradation corresponding to the amplitude of the image.

(Function) As a result, the reflected ultrasound waveform data from the adhesive surface of the object recorded according to the scanning position of the ultrasound probe is two-dimensional between the probe position and the time axis of the ultrasound waveform data. The amplitude of the RF waveform of the ultrasonic waveform data described above can be displayed on the display/recorder by associating it with the color gradation on the coordinates, so it is possible to see the phase change of the ultrasonic waveform reflected from the adhesive surface at each probe position. Visual monitoring becomes possible.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the circuit configuration of the same embodiment. In the figure, 1 is an ultrasonic transceiver, and an ultrasonic probe 2 is connected to this ultrasonic transceiver 1. The probe 2 is placed on a subject 3 made of different materials and is configured to transmit and receive ultrasonic waves. Further, a position detector 4 is connected to the ultrasonic probe 2 to detect its position in conjunction with scanning of the probe.

The ultrasonic reception signal from the subject 3 received by the ultrasonic transmitter/receiver S1 via the ultrasonic probe 2 is applied to the high-speed analog-to-digital converter 5, where it is converted into a digital waveform signal and sent to the probe. The probe position information of the second position detector 4 is stored in the digital memory 6. Then, the ultrasonic waveform data stored in the digital memory 6 is subjected to signal processing by a signal processor 7, and is supplied to a display/recorder 8 for image display.

Here, the signal processor 7 calculates the amplitude of the ultrasonic waveform, which is displayed on the two-dimensional coordinates of the probe position and the ultrasonic waveform, from the probe position information and the ultrasonic waveform data stored in the digital memory 6. It has the function of converting the image into an image display signal associated with color gradation, and the function of controlling the operation of the analog-to-digital converter 5 based on the position information from the position detector, and is configured by a microprocessor. are doing. The display/recorder 8 is a color CRT for displaying color images.
Or it consists of a color printer.

Next, the operation of the embodiment configured as described above will be explained. In this case, the object 3 is made of a different material 3a as shown in FIG.
, 3b are bonded together, and a case will be described in which the condition of 71 creases on the bonded surface 3C of the subject 3 is inspected. In this case, the ultrasonic probe 2 is arranged on the flaw detection surface so that the acoustic impedance 21 of the material 3a on the flaw detection surface side is smaller than the acoustic impedance Z2 of the other material 3b.

From this state, while scanning the surface of the subject 3 with the ultrasound probe 2, the reflected waveform from the contact surface 3C of the subject 3 is transmitted to the ultrasound transmitter/receiver 1 at each predetermined probe position. The signal is then converted into a digital signal by a high-speed analog-to-digital converter 5, and then stored in the memory 6 together with the probe position information from the position detector 4. At this time, the analog-to-digital converter 5 converts the ultrasonic reception signal output from the ultrasonic transceiver 1 into a digital signal without changing the RF waveform.

In this way, the ultrasonic waveform data for each probe position is sequentially recorded in the digital memory 6, but at the same time, the ultrasonic waveform data at this time is converted into an image by the signal processor 7 and provided to the display/recorder 8. You will be able to do it. In this case, the signal processor 7 outputs an image display signal that correlates the amplitude of the RF waveform in color on the two-dimensional coordinates of the probe position and the time axis of the ultrasonic waveform, so the display record Vessel 8
A color gradation two-dimensional image is displayed.

In this state, as shown in FIG. 2(a), if there is a partial notch 3d on the adhesive surface 3C of the subject 3, the ultrasonic transmission and reception waveform 10 with respect to the probe position X is as shown in FIG. It changes as shown in b). In other words, the probe position x1.corresponds to the adhesive part that is in reliable contact. At x5, since the relationship between the acoustic impedance Z1 of the material 3a and the acoustic impedance Z2 of the material 3b is z<z2, the reflected wave e from the adhesive surface has the same phase as the incident wave, but At the corresponding probe position It is in opposite phase to the wave. This means that at the probe positions X 1 + X 5 and x 3, the reflected waveform e1
This means that the waveforms are detected with opposite polarity. On the other hand, the probe position X2 at the boundary between the adhesive part and the 71 crevice part 3d,
At X4, the amplitude of the reflected waveform e1 becomes small because waveforms of opposite phases from each are detected in a summed form.

When the received ultrasonic waveform 10 for each probe position X, , X, is recorded in the digital memory 6 in this way, the signal processor 7 Position X and
An image display signal is generated in which the amplitude of the waveform is associated with color gradation 11 on the two-dimensional coordinates of time t of the waveform, and image display 1 is generated.
2 on the display/recorder 8. The reflected waveform e1 from the adhesive surface 3C of the subject 3 according to the image display 12 obtained in this way is displayed as a colored striped pattern in the X-axis direction of the probe position, and the RF waveform is displayed in color gradation. Therefore, the phase change of the waveform with respect to the probe position is clearly displayed. As a result, the boundary position X between the adhesive part and the peeling part 3d
Since the striped pattern is displayed in reverse at 2. In addition, the ultrasonic reflectance of the peeling part 3d is equal to R-1, whereas in the adhesive part, the reflectance is R<1 due to the difference in acoustic impedance, so the color scale is The intensity distribution of the reflected waveform with respect to the probe position can be seen on the product by displaying the image of the ultrasonic wave reflected from the adhesive surface as a scale display, so not only the phase change due to peeling but also the amplitude change can be taken into account. It also becomes possible to detect peeling.

[Effects of the Invention] As described above, according to the present invention, the ultrasonic wave reflected from the adhesive surface inside the object by the ultrasonic probe scanning the surface of the object is digitized in the form of an RF waveform. The ultrasound data recorded by the ultrasound probe is displayed on a two-dimensional coordinate system based on the ultrasound probe position and the time axis of the ultrasound waveform, with the amplitude of the waveform associated with color gradation. Since the color gradation striped pattern is made to correspond to the phase change and amplitude change of the reflected waveform in the child position direction, it is possible to visually inspect the peeling condition of the adhesive surface easily and with high precision.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, and FIG. 2 is a diagram for explaining the operation of the embodiment. 1... Ultrasonic transmitter/receiver, 2... Ultrasonic probe, 3...
...Test, 3a...Material I, 3b...Material ■, 3
C... Adhesive surface, 3d... Peeling part, 4... Position detector, 5... Analog-digital converter, 6...
Digital memory, 7... Signal processor, 8... Display recorder, 10... Ultrasonic reception waveform, 11... Image display, 12... Color gradation level.

Claims (1)

[Claims] An ultrasonic probe scans the surface of an object made by bonding dissimilar materials, and the ultrasonic reflected waveform from the adhesive surface inside the object detected by this ultrasonic probe is shown above in the form of an RF waveform. A storage means for storing the position information of the probe, and the amplitude of the ultrasonic RF waveform on a two-dimensional coordinate based on the ultrasonic probe position and the ultrasonic propagation time axis are mapped in color gradation. An ultrasonic flaw detection apparatus comprising: a signal processing means for outputting an image display signal; and a display recording means for displaying the image display signal produced by the signal processing means.