JPS61286750A - Method for flaw detection by standing wave of ultrasonic wave - Google Patents
Method for flaw detection by standing wave of ultrasonic waveInfo
- Publication number
- JPS61286750A JPS61286750A JP60129190A JP12919085A JPS61286750A JP S61286750 A JPS61286750 A JP S61286750A JP 60129190 A JP60129190 A JP 60129190A JP 12919085 A JP12919085 A JP 12919085A JP S61286750 A JPS61286750 A JP S61286750A
- Authority
- JP
- Japan
- Prior art keywords
- phase difference
- standing wave
- probe
- flaw detection
- ultrasonic waves
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Abstract
Description
【発明の詳細な説明】
(産業上の利用分野)
本発明は木質系材料同複合材料等探傷対象物の内部欠陥
を、探傷対象物の内部に送信した超音波がその内部で自
然に干渉してできた波(以下、本発明で定在波という。[Detailed Description of the Invention] (Industrial Application Field) The present invention detects internal defects in a flaw detection target such as a wood-based material or a composite material by naturally interfering with ultrasonic waves transmitted inside the flaw detection target. waves (hereinafter referred to as standing waves in the present invention).
)を用いて探傷する分野に利用される。) is used in the field of flaw detection.
(従来の技術)
本発明が適用できる木材工業界においては従来、丸太材
内部の欠陥を長年の経験から得られていた勘に基づく目
視検査により推定しでいた。ごく最近、金属材料等の非
破壊検査に利用していた超音波探傷方法が木材の内部欠
陥の探傷に試みられている。この方法では、木材の一万
の端から他方の端に超音波を透過させる透過法か、或い
は一万の端から発信した超音波が内部欠陥により反射し
て戻る波?測定する反射法があるが、これらには次のよ
うな問題点があり箋まだ材料の内部欠陥の探傷に利用す
ることは難しい現況である。(Prior Art) In the woodworking industry to which the present invention is applicable, defects inside logs have conventionally been estimated by visual inspection based on intuition gained from many years of experience. Very recently, ultrasonic flaw detection methods, which have been used for non-destructive testing of metal materials, have been attempted to detect internal defects in wood. In this method, is there a transmission method in which ultrasonic waves are transmitted from one end of the wood to the other end, or is the ultrasonic wave emitted from the end of the wood reflected back by internal defects? There are reflection methods for measuring, but these have the following problems, and it is currently difficult to use them to detect internal defects in materials.
即ち、年輪と木部が共存する木材のような不均質材料で
は、その中をできるだけ減衰しないで伝播させるために
は低周波の超音波を利用する必要がある反面、その指向
性が悪く、波の速変差に基づく差違分区別することに限
界がある。更に、受信波の到達時間を測定する際の受信
波形の立ち上がり時間(正確には到達した瞬間の時間ン
の判定に人為的判断誤差が伴い、この判定の端間が低い
場合には欠陥の探傷が不可能となる。また更に、低周波
を用いた反射法では送信波と反射波の干渉が生じてしま
い、反射波の抽出が困難である。In other words, in a heterogeneous material such as wood, where annual rings and xylem coexist, it is necessary to use low-frequency ultrasonic waves to propagate through the material with as little attenuation as possible. There is a limit to the ability to distinguish differences based on speed variations. Furthermore, when measuring the arrival time of the received wave, there is a human judgment error in determining the rise time (more precisely, the time at the moment of arrival) of the received waveform, and if the end of this judgment is low, it is difficult to detect defects. Furthermore, in the reflection method using low frequencies, interference occurs between the transmitted wave and the reflected wave, making it difficult to extract the reflected wave.
(発明が解決しようとする問題点)
本発明は上記従来の受信した波の時間差を基礎として内
部欠陥の有無を判定する方式の欠陥を、受信した波の形
の位相差により同じく有無を判定する方式により解消し
ようとするものである。(Problems to be Solved by the Invention) The present invention replaces the conventional method of determining the presence or absence of an internal defect based on the time difference between received waves by determining the presence or absence of an internal defect based on the phase difference in the shape of the received waves. This is an attempt to solve this problem through a method.
(問題点を解決するための手段]
本発明は、探傷対象物内部に1個或いは複数個の箇所か
ら発信した超音波が木質系材料の内外面でできる定在波
の位相を測定することによりその目的を達成する。(Means for Solving the Problems) The present invention measures the phase of standing waves generated on the inner and outer surfaces of a wood-based material by ultrasonic waves emitted from one or more locations inside an object to be detected. achieve that purpose.
ここで本発明の原理を第1図に基づいて説明するが、第
1図は定在波の位相が欠陥の存在によりずれることを定
性的に述べるものである。図において1および2は定在
波を受信する探触子、3は超音波を発信する探触子、4
は探傷対象物、5は内部欠陥、aおよびbは探触子6と
探触子1および2との配置間隔を示す。送信用探触子6
より超音波の連続波を送信すると、波は矢印で表す種々
の方向に伝わり、表面波、反射波および透過波の波動が
干渉し合って定在波を形成する。ここで探傷対象物4が
送信用探触子6を中心に材質的にまた彩状的に対称であ
れば、探触子3から等間隔にある探触子1および2から
得られる定在波の波形は同じ位相となる。しかし、図に
示すような欠陥5が対象物4の内に存在するとその欠陥
部分において超音波の屈折および反射が生じ、結果的に
欠陥部分側の定在波に乱れが生じる。この状態のもとで
受信用探触子1および2が受けたそれぞれの波形を比較
すると互いの位相がずれている。このように定在波の位
相の差違から内部欠陥の有無を調べることができる。本
発明は上記の原理を利用したものである。The principle of the present invention will now be explained based on FIG. 1, which qualitatively describes that the phase of a standing wave shifts due to the presence of a defect. In the figure, 1 and 2 are probes that receive standing waves, 3 is a probe that emits ultrasonic waves, and 4 is a probe that transmits ultrasonic waves.
denotes the object to be inspected, 5 denotes an internal defect, and a and b denote the spacing between the probe 6 and the probes 1 and 2. Transmission probe 6
When a continuous wave of ultrasonic waves is transmitted, the waves propagate in various directions indicated by arrows, and the surface waves, reflected waves, and transmitted waves interfere with each other to form a standing wave. Here, if the flaw detection target 4 is symmetrical in material and color with respect to the transmitting probe 6, the standing wave obtained from the probes 1 and 2, which are equally spaced from the probe 3, is The waveforms have the same phase. However, if a defect 5 as shown in the figure exists in the object 4, the ultrasonic waves are refracted and reflected at the defect, resulting in disturbance in the standing waves on the side of the defect. Comparing the respective waveforms received by receiving probes 1 and 2 under this condition, they are out of phase with each other. In this way, the presence or absence of internal defects can be investigated from the difference in the phase of the standing waves. The present invention utilizes the above principle.
(炸 用ン
本発明によれば前記の位相のずれは欠陥の大きさ、位置
および種類等によってその度合いが変るが、秋田着だ杉
丸太材の内部に存在する節欠陥を探傷した場合、その位
相のずれが約90変以上のしきい値を基準にして節欠陥
の存在を定量的に判定できるものである。また、前述の
定在波の測定箇所は2か所間時で穐なくても、1か所ず
つの位の
相を測定し記憶させ、その後で両者の位相へ差違を比較
することによっても欠陥の探傷はできるものである。更
に、本発明では使用した超音波の周波数は探傷対象物の
性状や探傷欠陥により任意に選択することができる。木
質系材料を対象にした場合1〜i Q Kl(Z程度の
周波数が適当である。また、このことは探傷対象物が均
一材料になればなるほど高い範囲の周波数の超音波を用
いることにより微少な内部欠陥をも捕えることが可能で
あムまた更に、本発明では探傷対象物に探触子を密着さ
せる方法として、探触子底面に突き出たピンを介して超
音波を伝える手段を用い、従来の接触媒体の添加或いは
接着材の塗布または機械的密着等の作業性の悪さを改善
するとともに、探触子の位置決め精實を高めることがで
きる。(According to the present invention, the degree of the above-mentioned phase shift varies depending on the size, position, type, etc. of the defect, but when a knot defect existing inside an Akita cedar log is detected, The existence of a node defect can be determined quantitatively based on a threshold value of a phase shift of about 90 degrees or more.In addition, the measurement points of the standing waves mentioned above can be measured at two locations. Alternatively, defects can also be detected by measuring and memorizing the phase of each location, and then comparing the difference between the two phases.Furthermore, in the present invention, the frequency of the ultrasonic waves used is It can be selected arbitrarily depending on the properties of the object to be detected and the defects to be detected.When targeting wood-based materials, a frequency of about 1 to i Q Kl (Z is appropriate.This also means that the object to be detected is uniform It is possible to detect even minute internal defects by using ultrasonic waves with a higher frequency range as the material becomes more sensitive. By using a means of transmitting ultrasonic waves through pins protruding from the bottom of the probe, it improves the poor workability of conventional methods such as adding a contact medium, applying adhesive, or mechanical adhesion, and improves the precision of positioning the probe. can be increased.
(実施例〉
本発明の実施例を図に基づいて詳細に説明すると、まず
、比較的鍵年輪層が薄いといわれているラワン板材の内
部欠陥探傷の実施例を示すと、第2図は探傷対象物4で
あるラワン板材の定在波探傷装置の説明図で、ラワン板
材の探傷面Aの中心に密着させた探触子3を介して信号
発生器6から0.2xaz毎に1KHzからi Q K
Hzまでの正弦波形の超音波?送信する。発生した定在
波は探触子3から60gの等間隔に配置した探触子1お
よび2により受信する。この態様において内部欠陥の有
無にょる定在波の位相差を調べてみると、第3図はラワ
ン板材の定在波が内部欠陥5に代えた切り込み溝5′が
入れていない状態での定在波の位相差を示すグラフであ
りSN4図は切り込みl115′を入れた状態での同じ
くグラフであるが、第3図においては周波数2JKHz
を送信した際110変程度、入’l KHzで60度は
どの位相差をもつ定在波を示す。次に第2図において、
探触子3の位置から底面Bに垂線をおろした点から底面
にそって6cWA右へ離れた点に深さ4備の切り込み構
5′を入れた状態の定在波の位相差は、第4図から明ら
かなように周波数2、f3 KHzgの所で約180度
、7.2KHzテ約110闇であり、いずれの周波数に
おいても切り込み溝が存在することにより約50度はど
位相差が高くなっている。このように無欠陥時の位相差
特性を予め把握し、探傷対象物に応じて設定した位相差
のしきい値を越える位相差が認められた場合には内部欠
陥の存在を推定できるものである。(Example) An example of the present invention will be explained in detail based on the drawings. First, an example of internal defect detection of a lauan plate material, which is said to have a relatively thin key annual ring layer, is shown in Fig. 2. This is an explanatory diagram of a standing wave flaw detection device for a lauan plate material, which is a target object 4, in which a signal generator 6 transmits signals from 1 KHz to i every 0.2xaz via a probe 3 that is brought into close contact with the center of the flaw detection surface A of the lauan plate material. QK
Sine wave ultrasound up to Hz? Send. The generated standing waves are received by probes 1 and 2, which are arranged at equal intervals of 60 g from probe 3. When examining the phase difference of the standing waves depending on the presence or absence of internal defects in this embodiment, Fig. 3 shows that the standing waves of the lauan plate are stable in a state where the notched grooves 5' are not inserted instead of the internal defects 5. This is a graph showing the phase difference of existing waves, and the SN4 diagram is the same graph with a notch 115' added, but in Figure 3, the frequency is 2JKHz.
A standing wave with a phase difference of about 110 degrees when transmitted and 60 degrees at input KHz indicates a standing wave. Next, in Figure 2,
The phase difference of the standing wave when a notch 5' with a depth of 4 is made at a point 6 cWA to the right along the bottom from the point drawn from the perpendicular line from the position of the probe 3 to the bottom surface B is As is clear from Figure 4, the phase difference is about 180 degrees at frequency 2, f3 KHzg, and about 110 degrees at 7.2 KHz, and the phase difference is about 50 degrees high at both frequencies due to the presence of the groove. It has become. In this way, the phase difference characteristics when there are no defects can be ascertained in advance, and if a phase difference that exceeds a phase difference threshold set according to the object to be detected is observed, the presence of an internal defect can be estimated. .
第2の実施例として樹皮つきの造林杉丸太の内部欠陥の
探傷例を示す。第5図は丸太材の定在波探傷装置の説明
図である。図において探傷対傷物4である丸太材の長手
方向(母線)に直角な面(丸太材端面と平行な面)の輪
郭(外周線)にそって探触子6を\まだ等間隔に探触子
1および2を配置する。この例においても探傷対象物か
ら得られる定在波の位相差は丸太材の年輪分布、丸太材
断面の真円度、内部欠陥の大きさ、形状等により異なる
。また、探触子6より送信する超音波の周および2の位
置がある一定の相対的関係になった場合にその定在波の
位相差は大きく変化する。即ち、その相対的関係に近づ
くにつれて位相差は初め大きく増え、その後で急激に減
少する。逆に、その関係から遠のくにつれて位相差は再
び大きくふえるという、いわゆる谷間現象を呈する〇第
7図は予め内部欠陥が知られている丸太材について探傷
した際の材料横断面上での定在波の位相差を円形座標図
で示したもので、内部欠陥は後述の円IN目盛11およ
び32付近に存在することが確められている。図におい
て半径方向の値は位相差の大きさP衷わし、外周線に相
当する半径の位相差は108度を表わす0外周線上の目
盛は探傷時の探触子乙の位置を示すものである。探触子
1および2は探触子3よりそれぞれ2目盛ずつ等間隔に
置かれている。第7図においては、しきい値が90度以
上の位相差をもつ谷間現象を呈する領域は円周目盛11
および32を中心とする2箇所に存在しており、予め測
定しである内部欠陥の存在位置にほぼ対応している。As a second example, an example of detecting internal defects in a silvicultural cedar log with bark will be shown. FIG. 5 is an explanatory diagram of a standing wave flaw detection device for log materials. In the figure, the probe 6 is probed at regular intervals along the contour (circumferential line) of a surface perpendicular to the longitudinal direction (generating line) of the log material (parallel to the end surface of the log material), which is the object 4 to be tested for flaws. Place children 1 and 2. In this example as well, the phase difference of the standing waves obtained from the flaw detection object varies depending on the annual ring distribution of the log, the circularity of the cross section of the log, the size and shape of the internal defect, etc. Further, when the circumference of the ultrasonic wave transmitted from the probe 6 and the position of the ultrasonic wave 2 have a certain relative relationship, the phase difference of the standing wave changes greatly. That is, as the relative relationship approaches, the phase difference initially increases greatly and then rapidly decreases. On the other hand, as the distance from this relationship increases, the phase difference increases again, exhibiting a so-called valley phenomenon. Figure 7 shows standing waves on the cross section of a log material with known internal defects. The phase difference is shown in a circular coordinate diagram, and it has been confirmed that internal defects exist near circle IN scales 11 and 32, which will be described later. In the figure, the value in the radial direction is the magnitude of the phase difference P, and the phase difference in the radius corresponding to the outer circumference line is 108 degrees.The scale on the outer circumference line indicates the position of the probe B during flaw detection. . Probes 1 and 2 are each placed at equal intervals of two scales from probe 3. In FIG. 7, the area where the threshold value exhibits a valley phenomenon with a phase difference of 90 degrees or more is at circumferential scale 11.
and 32, which approximately correspond to the positions of internal defects measured in advance.
(発明の効果)
本発明は以上説明したように従来の超音波探傷方法とは
全く違った新しい原理である定在波の位相差を測定する
ことにより、探傷対象物の種類、寸法および探傷技術の
熟練度等に無関係に内部欠陥を探傷できる効果がある。(Effects of the Invention) As explained above, the present invention measures the phase difference of standing waves, which is a new principle completely different from conventional ultrasonic flaw detection methods, to improve It has the effect of detecting internal defects regardless of the skill level of the person.
図面は本発明の実施fR?r−示し、第1図は本発明の
超音波の定在波探傷方法の説明図、第2図は板材に適用
した本発明の第1実施例の説明図1第6S4図は第1実
施例の探傷効果を示す位相差のグラフ1第5図は第2実
施例として丸太材に適用した探傷装置の説明図、第6図
は第5図のA −A ’断面図、第7図は丸太材内部欠
陥の位置標定の効果を示すグラフである。
図中、1および2は受信用探触子、3は発信用探触子、
4は探傷対象物、5は内部欠陥、6は超音波信号発生器
、7はオシロスコープ。Is the drawing an implementation of the present invention? Fig. 1 is an explanatory diagram of the ultrasonic standing wave flaw detection method of the present invention, Fig. 2 is an explanatory diagram of the first embodiment of the present invention applied to plate materials, Fig. 1, and Fig. 6S4 are the first embodiment. Graph 1 of the phase difference showing the flaw detection effect of Fig. 5 is an explanatory diagram of the flaw detection device applied to log materials as a second embodiment, Fig. 6 is a cross-sectional view taken along line A-A' in Fig. 5, and Fig. 7 is a log It is a graph showing the effect of positioning of defects inside the material. In the figure, 1 and 2 are receiving probes, 3 is a transmitting probe,
4 is an object to be inspected, 5 is an internal defect, 6 is an ultrasonic signal generator, and 7 is an oscilloscope.
Claims (3)
方法において、木質系材料に1個或いは複数個の探触子
から発信した超音波による定在波の位相を測定すること
により、内部欠陥の有無を判定することを特徴とする定
在波探傷方法。(1) A method of non-destructively detecting internal defects using ultrasonic waves, which involves measuring the phase of a standing wave caused by ultrasonic waves emitted from one or more probes into a wood-based material. , a standing wave flaw detection method characterized by determining the presence or absence of internal defects.
して探触子との密着を行うことを特徴とする特許請求の
範囲第(1)項記載の超音波の定在波探傷方法。(2) Ultrasonic standing wave flaw detection according to claim (1), characterized in that a protruding pin is provided on the bottom of the probe, or the probe is in close contact with the probe via the pin. Method.
方法において、木質系材料に1個或いは複数個の探触子
から発信した超音波による定在波の位相を、複数の測定
箇所で同時に或いは別箇に独立して測定し比較すること
により、得られた位相差を探傷対象物に対応したしきい
値を基準として内部欠陥の有無の判定に用いることを特
徴とする超音波の定在波探傷方法。(3) In a method of non-destructively detecting internal defects using ultrasonic waves, the phase of a standing wave generated by ultrasonic waves emitted from one or more probes to a wood-based material is measured multiple times. Ultrasonic waves that are characterized by measuring and comparing the phase differences simultaneously or separately at different locations, and using the obtained phase difference to determine the presence or absence of internal defects using a threshold value corresponding to the object to be detected as a reference. standing wave flaw detection method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP60129190A JPS61286750A (en) | 1985-06-13 | 1985-06-13 | Method for flaw detection by standing wave of ultrasonic wave |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP60129190A JPS61286750A (en) | 1985-06-13 | 1985-06-13 | Method for flaw detection by standing wave of ultrasonic wave |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS61286750A true JPS61286750A (en) | 1986-12-17 |
JPH0431350B2 JPH0431350B2 (en) | 1992-05-26 |
Family
ID=15003367
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP60129190A Granted JPS61286750A (en) | 1985-06-13 | 1985-06-13 | Method for flaw detection by standing wave of ultrasonic wave |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS61286750A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6684705B1 (en) * | 1999-05-07 | 2004-02-03 | U.S. Natural Resources, Inc. | Roller mechanism using an array of ultrasound elements to interrogate wood properties |
KR100604415B1 (en) | 2005-04-04 | 2006-07-25 | 재단법인서울대학교산학협력재단 | Wood deterioration computed tomography inspection method |
JP2008026162A (en) * | 2006-07-21 | 2008-02-07 | Sekisui Chem Co Ltd | Inspection method for inspecting deterioration state of embedded pipe |
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JPS5393886A (en) * | 1977-01-27 | 1978-08-17 | Kansai Electric Power Co | Inspection method of steel pipe materials |
JPS5713351A (en) * | 1980-06-03 | 1982-01-23 | Unisearch Ltd | Method of and apparatus for detecting decomposition in wood |
-
1985
- 1985-06-13 JP JP60129190A patent/JPS61286750A/en active Granted
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JPS5393886A (en) * | 1977-01-27 | 1978-08-17 | Kansai Electric Power Co | Inspection method of steel pipe materials |
JPS5713351A (en) * | 1980-06-03 | 1982-01-23 | Unisearch Ltd | Method of and apparatus for detecting decomposition in wood |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6684705B1 (en) * | 1999-05-07 | 2004-02-03 | U.S. Natural Resources, Inc. | Roller mechanism using an array of ultrasound elements to interrogate wood properties |
KR100604415B1 (en) | 2005-04-04 | 2006-07-25 | 재단법인서울대학교산학협력재단 | Wood deterioration computed tomography inspection method |
JP2008026162A (en) * | 2006-07-21 | 2008-02-07 | Sekisui Chem Co Ltd | Inspection method for inspecting deterioration state of embedded pipe |
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Publication number | Publication date |
---|---|
JPH0431350B2 (en) | 1992-05-26 |
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