JPH06317568A - Ultrasonic flaw detection apparatus - Google Patents

Abstract

PURPOSE:To detect a flaw with high accuracy without being influenced by a plate thickness by a method wherein a plurality of ultrasonic detectors which are adjacent to each other are operated simultaneously, obtained detection signals are compared with a set value and a thick material to be detected such as a composite material or the like can be inspected. CONSTITUTION:Multiplexers 5a to 5d are connected to multiplexers 5a1, 5d1, an oscillator 3 is driven, and ultrasonic impulses are applied simultaneously to the part of a material, to be detected, which is brought into close contact with detectors 6a1 to 6d1. Ultrasonic reflected echo signals from the material 7 to be detected are read out by a memory 21 through a CPU 20 via the multiplexers 5a1 to 5d2, receiving buffers 14a to 14d and analog input devices 12a to 12d. In this manner, the adjacent detectors 6a1 to 6d1 in a plurality are operated simultaneously, and the reflected echo signals from the material 7 to be detected are data-collected and operated by a computer system in this manner. As a result, even the thick plate member of a composite material can be inspected. In addition, since a set value to judge a flaw is made small along the direction of a plate thickness, the accuracy of the title apparatus is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flaw detector for nondestructively inspecting defects in a material to be inspected, and is particularly suitable for inspecting defects in thick materials to be inspected such as composite materials used in aircraft. The present invention relates to an ultrasonic flaw detector.

[0002]

2. Description of the Related Art Conventionally, an ultrasonic flaw detector has been used as a nondestructive inspection for defects in a material to be inspected. Figure 6
FIG. 2 is a block diagram showing an ultrasonic flaw detector that two-dimensionally inspects defects of a composite material used in an aircraft with a plurality of detectors, and 2 is an ultrasonic reception signal and a defect judgment value A
Comparator for comparing with, 3 is an oscillator, 4 is a receiver,
Reference numeral 5 is a multiplexer, 6 is an ultrasonic detector group, 7 is a composite material (test material), and 8 is a measuring instrument such as an oscilloscope.

FIG. 7 shows the arrangement of the ultrasonic detector group 6 and shows that the detectors are two-dimensionally arranged vertically and horizontally. FIG. 8 shows an ultrasonic reception signal.

The impulse signal from the oscillator 3 is applied to one detector 6a in the detector group 6 selectively connected by the multiplexer 5. The detector group 6 is brought into close contact with a test material 7 such as a composite material used in an aircraft, and the impulse signal 8a is converted into ultrasonic impulses by the detector 6a and transmitted to the test material 7. The reflected echo 8f1 from the defect 7f1 and the reflected echo 8b from the plate edge of the test material 7 are input to the receiver 4 again via the detector 6a and the multiplexer 5.

The signal from the receiver 4 is visualized by a measuring instrument 8 such as an oscilloscope and, at the same time, is compared with a defect set value A by a comparator 2 and detected as a defect signal B when the defect set value A is exceeded. . Multiplexer 5
The ultrasonic wave is switched at every time Tb when the reflection echo 8b from the plate end of the test material 7 is detected,
The test material 7 is two-dimensionally detected by sequentially switching the detector group 6 and oscillating and receiving ultrasonic signals.

[0006]

In order to secondarily detect a defect of a composite material used in an aircraft by ultrasonic flaw detection without removing it from the aircraft, it is necessary to detect it by a reflection method. . Further, in order to be able to closely adhere to the curved surface of the composite material, each detector needs to have flexibility.
For a detector that satisfies these conditions, the applicable thickness of the composite material is 6 mm or less, and it is impossible to inspect a thickness greater than this. The application of composite materials to aircraft is increasing, and the plate thickness thereof is also increasing, and it is necessary to inspect about 20 mm, which is a problem.

As a method of automatically detecting a defect in a material to be inspected, conventionally, when the reflected echo signal from the material to be inspected is larger than a defect set value A of a certain level, it is detected that the material to be inspected has a defect. . On the other hand, the sound wave intensity of the ultrasonic impulse applied to the test material is attenuated along the plate thickness direction. Therefore,
The reflection echo from a defect deep in the plate thickness direction is
It is smaller than the echo reflected from a shallow defect. Therefore, if the level of the defect set value A is constant,
There is a problem that defects in deep areas cannot be detected. This will be described with reference to FIG.

FIG. 8A shows a defect 7f1 of the test material 7 in FIG.
It is a recording signal of the measuring instrument 8 when inspected. Figure 8 (a)
Then, since the reflection echo 8f1 from the defect 7f1 is larger than the defect set value A, it is determined to be a defect. Defect 7f2 is 7f1 in FIG.
And the size is the same, but the position is only deep, and the record is shown in FIG. 8 (b). In the same figure, the reflection echo 8f2 from the defect 7f2 is smaller than the defect set value A, so it is not judged as a defect. In this case, if the defect setting value A is reduced to A ', the noise 8n1 is erroneously determined as a defect.
The defect set value cannot be lowered to A '.

The present invention has been made in view of the above circumstances, and an object thereof is to enable the inspection of a thick test material such as a composite material, which is impossible by the conventional method, and the plate thickness. An object of the present invention is to provide an ultrasonic flaw detector capable of highly accurate defect detection that is not affected by

[0010]

In order to solve the above problems, the present invention employs the following configurations. That is, the present invention provides a means for simultaneously operating a plurality of ultrasonic detectors adjacent to each other in an ultrasonic flaw detector for two-dimensionally inspecting a defect of a test material by a plurality of ultrasonic detectors, and a thickness of the test material. A means for reducing a set value for determining a defect along a direction, and a means for comparing the detection signal obtained by the ultrasonic detector with a set value to determine the presence or absence of a defect. To do.

[0011]

In the conventional two-dimensional ultrasonic flaw detector, since only one detector is operated in sequence, it is not possible to utilize the spread of the sound wave to the adjacent portion. In the present invention, by simultaneously operating a plurality of detectors adjacent to each other, the sound wave intensity of the detector portion to be inspected is added due to the spread of the sound waves from the adjacent detectors, so the sound wave intensity becomes strong, and in the conventional method. It enables inspection of thick plate composite materials, which was not possible.

As shown in FIG. 5, ultrasonic waves spread along the direction of the detector axis. Therefore, as shown in FIG. 3, when four adjacent detectors of the detectors 6a1, 6b1, 6c1 and 6d1 are simultaneously operated, the sound wave intensity Ia1 of the test material portion in close contact with the detector 6a1 will be described later.
It becomes like the formula (1). Therefore, it can be seen that by simultaneously operating a plurality of detectors, the sound wave intensity becomes higher than in the case of operating one detector, and it becomes possible to inspect a thick test material.

In the method of automatically judging the defect of the material to be inspected, the set value for judging the defect is constant in the conventional method. In the present invention, considering the attenuation of the ultrasonic wave in the plate thickness direction,
By reducing the set value for determining a defect along the plate thickness direction, it is possible to detect a defect by the same determination standard in the plate thickness direction.

As shown in FIG. 2, the input sound wave intensity is attenuated along the plate thickness direction in the thickness direction as shown in the equation (2) described later. Therefore, by applying this attenuation characteristic to a set value for determining a defect and determining the set value for the defect by the formula (3) described later, the set value for the defect decreases in the plate thickness direction as indicated by Ef in FIG. Therefore, it becomes possible to automatically determine a defect in a deep place.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic flaw detector according to an embodiment of the present invention. This embodiment shows a configuration example in which the ultrasonic flaw detector is system-constructed by a computer.

A memory 21 and a data bus 10 are connected to the CPU 20, and an oscillator controller 11 for controlling the driving of the oscillator 3, a plurality of analog input devices 12a to 12d, and a plurality of multiplexer controllers are connected to the data bus 10. 13a to 13d and the display controller 16 are connected. The detector group 6 is connected to the plurality of multiplexers 5a to 5d, is selected by a selection signal from the multiplexer controllers 13a to 13d, and is received by each of the reception buffer devices 14a to 14d.
4d and the oscillator 3 are connected.

Oscillator 3 and each reception buffer circuit 14a-1
A diode 15 is connected to each of the detectors 4d and 4d so that ultrasonic reception signals are not mixed between different detectors. The display device 17 is connected to the display controller 16 and displays the measurement result as shown in FIG.

Arrangement of detectors and multiplexers 5a ...
When the number of 5d is 4, as shown in FIG. 3, two detectors 6a1 to 6d1 each having a length and a width are provided in the multiplexers 5a to 5d.
It corresponds to 5d. In addition, the detector 6
The next four detectors 6a2 to 6d2 adjacent to a1 to 6d1 are also connected by the multiplexers 5a to 5d.

Similarly, all the detectors are connected to the multiplexers 5a to 5d in groups of four, and can be switched by switching signals from the multiplexer controllers 13a to 13d.
Further, the detector group 6 is closely attached so that a defect of the test material 7 can be inspected.

Next, the operation of the computer system according to this embodiment will be described with reference to FIGS. FIG. 2 shows an ultrasonic reception signal. FIG. 4 shows the detector 6
It shows the defect determination process of the test material portion that is in close contact with a1, and the same method is applied to other detector portions.

First, by selecting and driving the multiplexers (step S1), the four multiplexers 5a to 5d are connected to 5a1 to 5d1 and then the oscillator 3 is driven (step S2), and the four detectors 6a1 to 6a1. An ultrasonic impulse is simultaneously applied to the portion of the material to be intimately adhered to 6d1 (step S3). The ultrasonic wave reflected echo signals from the test material 7 are detected by the detectors 6a1 to 6d1, the multiplexers 5a1 to 5d1, the reception buffers 14a to 14d, and the analog input devices 12a to 12d.
Is read into the memory 21 via the CPU 20 (step S4).

Next, after collecting the ultrasonic reflection echo data up to the plate edge of the test material 7, the total ultrasonic intensity Ia1 of the test material portion in close contact with the detector 6a1 is calculated as follows (step S5). ).

[0023] However, Ia1 is the total of the material to be inspected that is in close contact with the detector 6a1.
Combined sound wave intensity, Ia is the sound wave intensity from the oscillator 3, and ki is the data.
The spread of the sound waves of the detectors 6b1, 6c1, 6d1 is the detector.
6a1 is the ratio that affects the portion of the test material that is in close contact,
0 <ki <1.

Then, using this Ia1, a defect set value in consideration of attenuation of ultrasonic waves in the plate thickness direction is calculated as follows (step S6). That is, the input sound wave intensity Ia1 'is attenuated in the thickness direction as Ia1' = Ia1-{(Ia1-Ib) / Tb} .t (2) along the plate thickness direction. Therefore, this attenuation characteristic is applied to a set value for determining a defect, and Ef = (In / Ib) {Ia1− (Ia1−Ib) t / Tb} + α (3) is determined. However, In is the sound wave intensity of noise, Ib is the reflected sound wave intensity from the plate edge, Ia1 is the total sound wave intensity of the material to be inspected in close contact with the detector 6a1, t is the time after the oscillator is driven,
Tb is the time from the driving of the oscillator until the reflected sound wave from the plate edge reaches the detector 6a1, and α is a defect detection margin.

Then, this Ef is compared with the collected ultrasonic reflection echo data E, and when E> Ef ... (4), it is judged that there is a defect (step S7).

As described above, according to this embodiment, the plurality of detectors 6a1 to 6d1 adjacent to each other are simultaneously operated,
By using the computer system to collect and calculate the reflected echo signal from the test material 7,
It is possible to inspect even thick plate members of about 20 mm, although only composite materials with a thickness of about two dimensions can detect defects. Moreover, since the set value for determining defects along the plate thickness direction is reduced in consideration of the attenuation of ultrasonic waves in the plate thickness direction, it is possible to perform highly accurate automatic defect detection that is not affected by the plate thickness.

The present invention is not limited to the above embodiment. In the embodiment, four adjacent ultrasonic detectors are simultaneously driven, but the number of ultrasonic detectors simultaneously driven is not necessarily limited to four, but may be plural. In addition, within the scope of the present invention,
Various modifications can be implemented.

[0028]

As described above, according to the present invention, a plurality of detectors adjacent to each other are simultaneously operated and the spread of sound waves from the adjacent detectors is utilized, which is impossible with the conventional method. It is possible to inspect thick test materials such as composite materials. Further, by considering the attenuation of the ultrasonic wave in the plate thickness direction, by reducing the set value for determining the defect along the plate thickness direction, it becomes possible to detect the defect with high accuracy without being influenced by the plate thickness.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic flaw detector according to an embodiment of the present invention.

FIG. 2 is a diagram showing input / output signals of ultrasonic waves when an ultrasonic detector is activated.

FIG. 3 is a diagram showing a relationship in which a plurality of detectors are simultaneously operated.

FIG. 4 is a diagram showing calculation and operation contents of a computer system.

FIG. 5 is a diagram showing the spread of sound waves when a plurality of detectors are simultaneously operated.

FIG. 6 is a block diagram showing a schematic configuration of a conventional ultrasonic flaw detector.

FIG. 7 is a diagram showing an arrangement configuration of a conventional ultrasonic detector.

FIG. 8 is a diagram showing an ultrasonic reception signal in a conventional device.

[Explanation of symbols]

2 ... Comparator 3 ... Oscillator 4 ... Receiver 5 ... Multiplexer 6 ... Detector group 7 ... Test material 8 ... Measuring instrument 7f1, 7f2 ... Defect 8a ... Impulse signal 8f1 ... Reflection echo from defect 7f1 8f2 ... Reflection from defect 7f2 Echo 8n1 ... Reflected echo from noise 8b ... Reflected echo from plate edge 10 ... Data bus 11 ... Oscillator controller 12a-12d ...
Analog input device 13a to 13d ... Multiplexer controller 14a to 14d ... Reception buffer 15 ... Diode 16 ... Display controller 17 ... Display device 20 ... CPU 21 ... Memory

Claims (1)

[Claims] 1. An ultrasonic flaw detector for two-dimensionally inspecting defects in a material to be inspected by a plurality of ultrasonic detectors, a means for simultaneously operating a plurality of ultrasonic detectors adjacent to each other, and a thickness of the material to be inspected. And a means for reducing the set value for determining a defect along the depth direction, and a means for determining the presence or absence of a defect by comparing the detection signal obtained by the ultrasonic detector with the set value. Ultrasonic flaw detector characterized by.