JPS60202358A - Ultrasonic diagnosis - Google Patents

Abstract

PURPOSE:To make it possible to detect the shape and position of a flaw even if said flaw is present at the central part of an object to be examined, by calculating the modulation point of a graph based on a measured ultrasonic wave propagation time value by ultrasonic probes at plural positions of the outer periphery of a tomographic surface. CONSTITUTION:The ultrasonic wave from the probe provided to the fixed point P1 of the outer periphery of the cross-sectional area A of a wooden utility pole having a flaw H at the central part thereof is received by the other probes at plural points P2, P3 going away from the point P1 along the outer periphery to measure an ultrasonic wave propagation time. If the modulation point of a graph based on said propagation time and the distance between the fixed point and the measuring point is calculated, the position F1 of the flaw H is determined and, if the fixed point is altered and similar operation is repeated, the shape of the flaw H is determined. By this method, the shape and position of the flaw can be detected by using an ultrasonic wave even if said flaw is present at the central part of an object to be examined.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an ultrasonic meter fJJi method for diagnosing the shape J3 and position of a defective part inside an object to be measured using ultrasonic waves.

[Prior art]

An ultrasonic diagnostic method for relatively easily determining the location and shape of internal defects in large materials such as wood and plastic deck, which are susceptible to ultra-8-wave AR and large materials.
(There was a method shown in 1 (I57-'I15255 Bow).

For example, this method will be explained using the case of detecting a rotten part (defective part) of a wooden electric company. [Normal electricity I] Pine trees that are used for a long time have decayed parts 1-1 along the annual rings, as shown in Figure 1. Here, if the ultrasonic propagation time is measured with the probe in contact with position 1] 1 and Pl-, the propagation time between the diameters in the healthy area (for example, the measurement time can be obtained at a distance of 1 m or more from the ground) is approximately equal to On the other hand, when measuring the propagation time by touching the probe to Ps and Ps', there is a decayed part on the line connecting both probes, so the propagation of the ultrasonic wave goes around the decayed part. Therefore, the propagation time is longer than that of a healthy part, and the existence of a decayed part can be detected thereby.

However, the type of decay seen in Japanese pines is different from that in cedar; as shown in Figure 2, the center of the pine is rotten, but in many cases there is decay even in areas that are more than 100m above the ground. Therefore, with the conventional method, it was not possible to measure the ultrasonic propagation time in the healthy part C, and error 1 occurred where the propagation time at a location where the 111MJTJ part was located was determined to be the value of the healthy part.

Furthermore, in the case of the water column shown in Figure 2, P+ and P+-
Since the ultrasonic wave propagation times between , Ps, and Ps are equal (J), if the ultrasonic propagation time at all R is incorrectly measured, it may lead to a misjudgment even if it is a completely healthy part. There were some drawbacks.

[Purpose of the invention]

This invention was made in view of the above circumstances, and even if there is a defect in the center of the object to be measured, it is possible to detect both the shape and position of the defect using ultrasonic waves. The purpose is to provide a diagnostic method.

[Structure of the invention]

゛This invention radiates ultrasonic waves from one point to another point on the outer periphery of the object to be measured, and detects defects in the object based on the ultrasonic propagation between transmission and reception. In the ultrasonic diagnostic method that covers detection, the position of the probe is fixed,
The ultrasonic propagation time is measured at multiple positions while the other probe is kept away from the probe along the outer circumference, and the changes in the graph showing the relationship between the distance between the probes and the ultrasonic propagation time are calculated. It is characterized by detecting the position and shape of the defect by finding the curved point.

〔Example〕

FIG. 3 is an external view of a diagnostic device to which the method according to the present invention is applied;
2a and 2b are a transmitting probe and a receiving probe each using a normal Langevin type vibrator; 3 is a transmitting/receiving section; 2a, 2
b is a transmitting contact and a receiving probe each using a normal Langevin type transducer, and 3 is an ultrasonic wave emitted from the transmitting probe 2a until it is received by the receiving probe 2b. A digital display that displays the propagation time; 4 a digital display that displays the propagation time ratio of previous and subsequent measurements; 5G; 1 an image display that displays the shape and position of the defective part in the object to be measured; 6; is a minicomputer, and 7 is a power supply equipment. J3, digital table; J(:÷H3,/l
a; and both image displays 5 are liquid crystal displays.

Next, this super j'Ji wave diagnosis r (diagnosis W using the 71 device rl)
One method will be explained using an example of detecting a rotten part (defective part) of a wooden utility pole.

Figure 11 shows a wooden telephone pole with a rotten part in the center.
P+ is the position where the outer circumference is divided into '1G.

1)2. ...P+s and J-ru. First, the transmitting probe 2a is placed in position 1〕1 and the receiving probe 2b is brought into contact with position P2 to measure the distance between the propagations 11 and 1. Place only child 2b @1]
3, measure the propagation time again. As described above, the transmitting probe 2a remains fixed in position and only the receiving probe 2b is moved to position P4. Ps, P6 and 1]7 (measure the propagation time. At this time, the straight path 11f between both probes
ltL and Den 416 Hours 13! ” is shown in Figure 5. In Fig. 5, the receiving probe positions correspond to P++, P2, 3, P4, Ps, P6, P7, and Ps. As a result, P5 to 1] When moving to 6, 1 m Jtliu5 (you can see that it suddenly becomes 1). This is P1 and P6
This is because there is a decayed part 1 in the middle of the ultrasonic transmission path that connects the two. (As shown in Figure 1, the point that touches the decayed part is approximately 6ゎ'jan' (J.) at the midpoint F1 of the line connecting midpoints Q1 and P! of P5 and P6. , Similarly, 1) Set 3 as the transmitting probe 2a, and measure 1i'ill during propagation while changing the position of the receiving probe 211. Since the inflection point can be found in the same way as in Figure 15, the approximate point F2 that touches the H'S rotten part can be found.
s, P7, P9, pH, P+3, when measuring from one IS, Fl, F2..., 1:8 becomes 11
1, so if you connect them with an n line, the result in Figure 6 becomes 4.
Tl will be done.

As can be seen from the comparison between FIG. 4 and FIG. 6, according to the present invention, the position and shape of the rotten part of the building located in the center of the headquarters can be detected by a relatively simple method.

It is not always necessary to have 8 transmitting probe positions, and it is known that in the case of a Japanese pine tree that rots in the center, it rots within the center, so the number of approximation points 1. The measurement time can be shortened by reducing the number and approximating a curve between them.

〔Effect of the invention〕

As explained above, the method according to the present invention detects the position where the ultrasonic propagation path reaches the defective part by finding the inflection point in the relationship between the ultra-U wave probe distance Fil and the propagation time. As a result, the position and shape of the defective portion can be detected together, and as a result, the image jΦ can be reduced to 11 times. Therefore, there are 1 [16 advantages] in that repairs, nail rests, etc. can be carried out accurately after defects are discovered. Also,
According to the present invention, since it is possible to use ultrasonic waves with a frequency of 11 (comparatively), it is possible to obtain an advantage that the diagnostic device can be configured easily and inexpensively.As a result of the above, the method according to the present invention It is extremely effective in detecting defects in trees, houses, etc., and detecting defects in castings.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a workpiece such as cedar wood that has defects on its outer periphery, Figure 2 is a cross-section of a workpiece that has defects in the center such as Japanese pine, and Figure 3 is a method according to the present invention. Fig. 4 is an explanatory diagram of a method for diagnosing the rotten part of a wooden telephone pole using the apparatus shown in Fig. 3, and Fig. 5 shows the distance between the probes and the propagation. FIG. 6, a graph showing the relationship over time, is a diagram showing the state in which the decayed part of the wood shrine shown in FIG. 4 is imaged by the apparatus shown in FIG. 3. 1...Ultrasonic transmitting/receiving section, 2a...Transmitting probe, 2b...Receiving probe, 33, 4...
...Digital display, 5...Image display,
6...Mini]umpikota. Figure 1 b Figure 2 5

Claims (1)

[Claims] A measurement cross section is set in the object to be measured, and from a point on the outer periphery of this measurement cross section, point inward of the measurement cross section (with the lft1 wave as a rule, and the measured cross section In the ultrasonic diagnostic method of detecting a defective part in the object to be measured based on the ultrasonic propagation time between the transmitter and the receiver at another point on the outer circumference of the probe, By fixing the position and measuring the ultrasonic wave propagation time at multiple positions while avoiding other probes along the outer circumference, we determined the relationship between the distance between the probes and the ultrasonic propagation time. An ultrasonic diagnostic method characterized by detecting the position and shape of the defect by finding an epidemiological point in the graph shown.