JPH0324403A - Apparatus for measuring depth of crack - Google Patents
Apparatus for measuring depth of crackInfo
- Publication number
- JPH0324403A JPH0324403A JP16013689A JP16013689A JPH0324403A JP H0324403 A JPH0324403 A JP H0324403A JP 16013689 A JP16013689 A JP 16013689A JP 16013689 A JP16013689 A JP 16013689A JP H0324403 A JPH0324403 A JP H0324403A
- Authority
- JP
- Japan
- Prior art keywords
- crack
- electrodes
- potential difference
- current
- depth
- 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.)
- Pending
Links
- 239000002184 metal Substances 0.000 abstract description 17
- 238000009499 grossing Methods 0.000 abstract description 6
- 230000001360 synchronised effect Effects 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 2
- 238000001514 detection method Methods 0.000 description 27
- 238000000034 method Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 3
- 230000003321 amplification Effects 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 238000004313 potentiometry Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、金属など披４ＩＩｊ定体表而の亀裂の深さを
ａｌ定する（ＪＡ裂深さ測定装置に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a crack depth measuring device for determining the depth of a crack in a solid object such as metal (JA crack depth measuring device).
（従来の技術）
金属の表面に開口している亀裂の深さを非破地でｆｌＦ
ｊ定する方法としては、直流電流又は交流市流による電
位差法が広く使用されている。この電位差法は、金属に
一定の電流が流れているときに、金属表面の任意の２点
間の電位差がこの２点間の距離に比例することを応用し
たものである。(Prior art) Determine the depth of a crack that opens on the surface of a metal without breaking it.
As a method for determining j, the potential difference method using direct current or alternating current current is widely used. This potential difference method applies the fact that when a constant current flows through a metal, the potential difference between any two points on the metal surface is proportional to the distance between these two points.
第４図はかかる電α差法を応用した亀裂深さ測定装置の
構或図である。同図において１は金属であって、この金
属１には亀裂２が生じている。この金属１の表面上には
電流電極３，４が接触しており、これら電流電極３，４
は亀裂２を介して間隔ｇをおいて配置されている。そし
て、これら電流電極３，４の間には直流電源５又は交流
電源６が接続されている。又、これら電流電極３．４の
内側には電位差検出電極７，８が亀裂２を介して金属１
の表面上に間隔Ｐをおいて配置されている。FIG. 4 is a diagram showing the structure of a crack depth measuring device to which such an electro-α difference method is applied. In the figure, 1 is a metal, and a crack 2 has occurred in this metal 1. Current electrodes 3 and 4 are in contact with the surface of this metal 1, and these current electrodes 3 and 4
are arranged at a distance g across the crack 2. A DC power source 5 or an AC power source 6 is connected between these current electrodes 3 and 4. Further, inside these current electrodes 3.4, potential difference detection electrodes 7, 8 are connected to the metal 1 through the crack 2.
are arranged at a distance P on the surface of.
そして、これら電位差検出電極７．８には電位差計９が
接続されている。しかるに、各電流電極３．４に直流？
ｔｉ源５又は交流電源６から直流電流又は交流電流が供
給されると、このとき各電位差検出電極７，８間に現れ
る電位差が電位差計９によって検出され、この電位差か
ら亀裂２の深さｄが求められる。A potentiometer 9 is connected to these potential difference detection electrodes 7.8. However, is there direct current in each current electrode 3.4?
When a direct current or an alternating current is supplied from the ti source 5 or the AC power supply 6, the potential difference appearing between the potential difference detection electrodes 7 and 8 is detected by the potentiometer 9, and the depth d of the crack 2 is determined from this potential difference. Desired.
なお、以上のような装置では亀裂２の深さ測定に先立っ
て較正が行なわれる。この較正は２方法あり、先ず第１
方法は所定深さの人工亀裂が形成された較正用試験片を
用意し、この較正用試験片の亀裂の無い部分（ｄ−０）
及び既知の人工亀裂深さｄでの各電位差検出電極７．８
間のそれぞれの電位差を検出して、これらの電位差の表
示値が亀裂深さ（ｄ−０及びｄ）に対応するようにゲイ
ンを調整の後、亀裂２の深さを測定するものである。次
に第２方法は例えば金属１の亀裂２の無い部分を使用し
て各電位差検出電極７，８間の電位差Ｖ。を求め、この
亀裂深さｄ − ０ ＋ｕ＋の場合の電位差■。を基準
電位差として例えばマイクロコンピュータに記憶させて
おく。そして、この電位差ｖｏは被検査体の電気抵抗率
ρと各電位差検出電極７，８の間隔Ｐに比例するので、
亀裂２の深さ測定時の亀裂深さｄは、各電位差電極７．
８１ｕＪの電位差変化と電位差検出電極７．８の間隔変
化との比例関係からマイクロコンピュータで計算して求
めるものである。Note that in the above-described apparatus, calibration is performed prior to measuring the depth of the crack 2. There are two methods for this calibration.
The method is to prepare a calibration test piece in which an artificial crack of a predetermined depth has been formed, and to detect the crack-free part (d-0) of this calibration test piece.
and each potential difference sensing electrode 7.8 at a known artificial crack depth d.
The depth of the crack 2 is measured after detecting the respective potential differences between them and adjusting the gain so that the displayed values of these potential differences correspond to the crack depths (d-0 and d). Next, the second method uses, for example, a portion of the metal 1 without cracks 2 to measure the potential difference V between each potential difference detection electrode 7, 8. Find the potential difference ■ for this crack depth d − 0 + u+. is stored in, for example, a microcomputer as a reference potential difference. Since this potential difference vo is proportional to the electrical resistivity ρ of the object to be inspected and the distance P between the potential difference detection electrodes 7 and 8,
The crack depth d when measuring the depth of the crack 2 is determined by each potential difference electrode 7.
It is calculated by a microcomputer from the proportional relationship between the change in potential difference of 81 uJ and the change in the distance between the potential difference detection electrodes 7.8.
（発明が解決しようとする課題）
ところで、亀裂深さの測定では浅い亀裂から深い亀裂ま
で精度高く測定する要求があるが、上記直流又は交流に
よる測定では精度高い測定が困難となっている。直流電
流による電位差法では、非常に大きな電流を必要とする
ばかりか、各電位差検出電極７．８間に現れる電位差が
数十μＶ程度と小さいために大きな増幅処理が必要とな
る。ところが、直流電流に対して大きな増幅処理を行う
のは交流電流の増幅に比べて難しく、かつ不安定となり
易い。一方、交流電流による電位差法では被測定体の内
部の深いところに電流が流れにくく、このため深い亀裂
の深さ測定は困難となっている。(Problems to be Solved by the Invention) Incidentally, in measuring crack depth, there is a demand for highly accurate measurement from shallow cracks to deep cracks, but it is difficult to measure with high precision when measuring with the above-mentioned direct current or alternating current. The potential difference method using direct current not only requires a very large current, but also requires a large amplification process because the potential difference appearing between each potential difference detection electrode 7, 8 is small, about several tens of μV. However, performing large amplification processing on direct current is more difficult than amplifying alternating current, and tends to become unstable. On the other hand, in the potentiometric method using alternating current, it is difficult for the current to flow deep inside the object to be measured, making it difficult to measure the depth of deep cracks.
さらに、較正を行う場合、上記各方法とも各電位差検出
電極７，８間の電位差を検出するので、この電位差は各
電位差検出電極７，８と金属１との材質によって発生す
る接触起電力を含んだ値となっている。この接触起電力
は温度変化によって変化し数ｍＶに達することがあるた
め誤差発生の原因となっている。従って、亀裂深さｄを
求める際の較正はその誤差を含んだ状態で行なっており
、亀裂深さ測定の精度が悪くなっている。Furthermore, when performing calibration, each of the above methods detects the potential difference between the potential difference detection electrodes 7 and 8, so this potential difference does not include the contact electromotive force generated by the materials of the potential difference detection electrodes 7 and 8 and the metal 1. It has a value of This contact electromotive force changes with temperature changes and can reach several mV, causing errors. Therefore, the calibration for determining the crack depth d is performed with this error included, resulting in poor crack depth measurement accuracy.
そこで本発明は、深い亀裂から浅い亀裂までの深さを精
度高くかつ接触起電力の影響を受けない正確な測定がで
きる亀裂深さ測定装置を提供することを目的とする。SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a crack depth measuring device that can accurately measure the depth from a deep crack to a shallow crack with high precision and is not affected by contact electromotive force.
（課題を解決するための手段）
本発明は、被測定体の亀裂を介して被測定体表面上に配
置された一対の第１電極と、これら第１電極にパルス状
の直流電流を供給するパルス供給手段と、第１電極の内
側で亀裂を介して被測定体表面上に配置された一対の第
２電極と、これら第２電極間に現れる電位差から亀裂の
深さを算出する深さ算出手段とを備えて上記目的を達成
しようとする亀裂深さ測定装置である。(Means for Solving the Problems) The present invention provides a pair of first electrodes arranged on the surface of the object to be measured through a crack in the object to be measured, and a pulsed direct current is supplied to these first electrodes. A pulse supply means, a pair of second electrodes arranged on the surface of the object to be measured via a crack inside the first electrode, and a depth calculation for calculating the depth of the crack from the potential difference appearing between these second electrodes. This is a crack depth measuring device which attempts to achieve the above object by comprising means.
又、本発明は、被測定体の亀裂を介して被は−１定体表
面上に配置された一対の第１電極と、これら第１電極に
パルス状の直流電流を供給するパルス供給手段と、第１
電極の内側で亀裂を介して被測定体表面上に配置された
一対の第２電極と、第１電極と第２ｍ極との間で亀裂を
介して被測定体表面上に配置された少なくとも一対の第
３電極と、第２電極及び第３電極に現れる各電位差をそ
れぞれ受けて電位差変化に応じた較正値を求める較正手
段と、第２電極間に現れる電位差を受けこの電位差と較
正手段で求められた較正．値とにより亀裂の深さを算出
する深さ算出手段とを備えて上記目的を達成しようとす
る亀裂深さ測定装置である。The present invention also provides a pair of first electrodes disposed on the surface of the -1 constant body through a crack in the body to be measured, and a pulse supply means for supplying a pulsed direct current to the first electrodes. , 1st
a pair of second electrodes disposed on the surface of the object to be measured through a crack inside the electrodes; and at least one pair of second electrodes arranged on the surface of the object to be measured through a crack between the first electrode and the second m-pole. a third electrode, a calibration means that receives each potential difference appearing at the second electrode and the third electrode and calculates a calibration value according to the change in potential difference; calibration. This is a crack depth measuring device that attempts to achieve the above object, and includes a depth calculation means for calculating the depth of a crack based on the above-mentioned values.
（作 用）
このような手段を備えたことにより、被測定体の亀裂を
介して被ｆｌｌｌ＋定体表面上に配置された第１電極に
パルス供給手段からパルス状の直流電流を供給し、この
とき第１電極の内側で亀裂を介して被測定体表面上に配
置された一対の第２電極間に現れる電位差を用いて深さ
算出手段により亀裂の深さを算出する。(Function) With the provision of such a means, a pulsed direct current is supplied from the pulse supply means to the first electrode placed on the surface of the object to be measured through the crack of the object to be measured, and this At this time, the depth of the crack is calculated by the depth calculating means using the potential difference that appears between the pair of second electrodes arranged on the surface of the object to be measured via the crack inside the first electrode.
また、上記手段を備えたこことにより、被測定体の亀裂
を介して被測定体表面上に配置された一対の第１電極に
パルス供給手段からパルス状の直流電流を供給し、この
とき第２電極及び第３ｆｓ極に現れる各電位差を較正手
段は受けてこれら電位差変化に応じた較正値を求め、か
つ第２電極間に現れる電位差を受けこの電位差と較正手
段で求められた較正値とを用いて深さ算出手段により亀
裂の深さを算出する。Further, with the above-mentioned device, a pulsed direct current is supplied from the pulse supply means to the pair of first electrodes arranged on the surface of the object to be measured through a crack in the object to be measured, and at this time, the second The calibration means receives each potential difference that appears between the electrodes and the third fs electrode, and calculates a calibration value corresponding to the change in these potential differences, and receives the potential difference that appears between the second electrode, and uses this potential difference and the calibration value determined by the calibration means. The depth of the crack is calculated using a depth calculating means.
（実施例）
以下、本発明の一実施例について図面を参照して説明す
る。(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.
第１図は亀裂深さ測定装置の構成図である。この測定装
置はプローブ１０及び測定装置本体２０とから構成され
ている。プローブ１０の構成を説明すると、金属１の表
面上には亀裂２を介し間隔ｇをおいて第１電極である一
対の電流電極１】，１２が配置されるとともに、これら
電流電極１１，１２の内側で亀裂２を介して第２電極で
ある電位差検出電極１３．１４と第３電極である電位差
検出電極１５．１６がそれぞれ１対づつ配置されている
。このうち各電位差検出電極１３．１４は間隔Ｐ，をお
いて配置されており、又各電位差検出電極１５．１６は
間隔Ｐ２ （＞ＰＩ）をおいて配置されている。又、
これら電位差検出電極１３，１４と１５．１６とには切
換スイッチ１７の各端子が接続されている。FIG. 1 is a block diagram of a crack depth measuring device. This measuring device is composed of a probe 10 and a measuring device main body 20. To explain the configuration of the probe 10, a pair of current electrodes 1], 12, which are first electrodes, are arranged on the surface of the metal 1 with a gap g apart through a crack 2. A pair of potential difference detection electrodes 13.14 as a second electrode and a pair of potential difference detection electrodes 15.16 as a third electrode are arranged on the inside through the crack 2. Among these, each potential difference detection electrode 13, 14 is arranged with a spacing P, and each potential difference detection electrode 15, 16 is arranged with a spacing P2 (>PI). or,
Each terminal of a changeover switch 17 is connected to these potential difference detection electrodes 13, 14 and 15.16.
一方、測定装置本体２０は次のような構或となっている
。すなわち、パルス供給手段としてのバルス波発振器２
１が設けられ、このノくルス波発振器２１は第２図に示
すようなパルス幅Ａと間隔Ｂとの比Ａ／Ｂが数分の１以
下で、そのピーク電流値が例えば１Ａで平均電流は０．
２Ａ以下となるノくルス状の直流電流（以下、直流パル
ス電流と称する）を発生するものである。このノくルス
波発振器２１の出力電圧は定電流回路２２を制御して電
流電極１１．１２にパルス状電流を供給するように接続
されている。なお、パルス電流は制御ノくルスのピーク
電圧に比例したピーク電流で、ノ＜ルス電圧の正の特間
のみ流れるように制御された定電流回路２２を通して電
流電極１１．１２に供給されている。このパルス電流に
よって電位差検出電極１３．１４に生じた電位差は交流
増幅器２３で増幅され、その出力はパルス波発振器２１
のノくルス電圧で制御される同期検波器２４を通って検
波され、平滑回路２５で平滑化された電圧になる。この
平滑化された出力電圧をマイクロコンピュータ２６に送
るものである。このマイクロコンピュータ２６は平滑回
路２５の平滑出力電圧を受けてこの電圧値から亀裂２の
深さｄを算出する機能を有するものである。なお、この
マイクロコンピュータ２６にはディジタル表示器２７及
び設定器２８が接続されている。この設定器２８は各電
極１３，１４と１５．１６との各間隔Ｐ．，Ｐ２や比例
定数αが設定されており、かつ測定モード及び較正モー
ドとの各モードにセットされるようになっている。On the other hand, the measuring device main body 20 has the following structure. That is, the pulse wave oscillator 2 as a pulse supply means
1 is provided, and this Norms wave oscillator 21 has a ratio A/B of pulse width A and interval B as shown in FIG. is 0.
It generates a pulse-like DC current (hereinafter referred to as DC pulse current) of 2A or less. The output voltage of this Norms wave oscillator 21 is connected to control a constant current circuit 22 to supply a pulsed current to the current electrodes 11, 12. The pulse current is a peak current proportional to the peak voltage of the control pulse, and is supplied to the current electrodes 11.12 through a constant current circuit 22 that is controlled to flow only during the positive pulse voltage. . The potential difference generated between the potential difference detection electrodes 13 and 14 by this pulse current is amplified by the AC amplifier 23, and its output is sent to the pulse wave oscillator 21.
The voltage is detected through a synchronous detector 24 controlled by the Norms voltage, and is smoothed by a smoothing circuit 25 to become a voltage. This smoothed output voltage is sent to the microcomputer 26. This microcomputer 26 has a function of receiving the smoothed output voltage of the smoothing circuit 25 and calculating the depth d of the crack 2 from this voltage value. Note that a digital display 27 and a setting device 28 are connected to this microcomputer 26. This setting device 28 is used for each interval P between each electrode 13, 14 and 15.16. , P2 and a proportionality constant α are set, and are set in each mode of measurement mode and calibration mode.
ところで、この亀裂２の深さｄを算出する場合、マイク
ロコンピュータ２６は較正して深さｄを算出している。By the way, when calculating the depth d of this crack 2, the microcomputer 26 is calibrated to calculate the depth d.
ここで、較正法について説明する。Here, the calibration method will be explained.
この場合、金属１は亀裂２の無いもの、又は金属１の亀
裂２の無い部分に各電位差検出電極１３〜１６が配置さ
れる。そこで、設定器２８は較正モードにセットされて
パルス波発振器２１から各電流電極１１．１２間に直流
パルス電流が供給される。このとき、各電位差検出電極
１３．１４及び各電位差検出電極１５．１６間に現れる
各基準電位差Ｖ。１及びＶ。２は切換スイッチ１７を通
してそれぞれ交流増躯器２３で増都され、次の同期検波
器２４で険波されて平滑回路２５を通してマイクロコン
ピュータ２６に送られる。このマイクロコンピュータ２
６は各基準電位差Ｖ。１とび■。２との偏差を求め、こ
の一差を各電位差検出電極の間隔Ｐ，とＰ２との偏差で
除算して電位差変化率ΔＶｏ／ΔＰ．
＝ （ＶＯ２ Ｖｏｌ） ／ （ Ｐ ２ Ｐ ＋
）を求め、そうして材質に応じて予め設定された比例
定数αを上記変化弔に乗算して較正値を求める。In this case, the metal 1 has no cracks 2, or the potential difference detection electrodes 13 to 16 are arranged in a portion of the metal 1 where no cracks 2 are present. Therefore, the setting device 28 is set to a calibration mode, and a DC pulse current is supplied from the pulse wave oscillator 21 between each current electrode 11, 12. At this time, each reference potential difference V appears between each potential difference detection electrode 13.14 and each potential difference detection electrode 15.16. 1 and V. 2 are multiplied by the alternating current amplifiers 23 through the changeover switches 17, and are further increased by the next synchronous detector 24 and sent to the microcomputer 26 through the smoothing circuit 25. This microcomputer 2
6 is each reference potential difference V. 1 jump■. 2, and divide this difference by the deviation between the interval P of each potential difference detection electrode and P2 to obtain the potential difference change rate ΔVo/ΔP. = (VO2 Vol) / (P 2 P +
) is determined, and the above-mentioned change is multiplied by a proportionality constant α, which is preset according to the material, to determine a calibration value.
すなわち、
α（ＶＯ２ Ｖｏｗ） ／ （Ｐ２ Ｐ ＋ ）一
α・ΔＶＯ／ΔＰｏ ・・・（１）で
ある。そして、マイクロコンピュータ２６は亀裂２の深
さｄを次式から算出する。That is, α(VO2 Vow) / (P2 P + ) - α·ΔVO/ΔPo (1). Then, the microcomputer 26 calculates the depth d of the crack 2 from the following equation.
ｄ − ａ （Ｖ − Ｖ Ｈ）ＸΔＰｏ／ΔＶｏ”（
１／２）・・・（２〉
このように各電位差電極１３．１４及び１５．１６を用
いてΔＶＯ／ΔＰｏが求められるが、これは被測定体の
材質による抵抗率の差を補正するとともに、接触起電力
により生じる誤差も打ち消し合うことになる。ここで、
亀裂２の深さｄの測定により検出した電位？：：．■は
亀裂２が深くなると亀裂深さｄに比例的でなく、第３図
に示すように（’／ Ｖｏｗ） − ｏｏｄ
−（３）のような関係の曲線となる。上記第
〈３〉式の指数ｍは測定電位差Ｖと亀裂深さｄとの関係
を両対数表示するとき、その曲線の傾きから求められる
。d − a (V − V H)XΔPo/ΔVo”(
1/2)...(2> In this way, ΔVO/ΔPo is obtained using each potential difference electrode 13.14 and 15.16, but this is done by correcting the difference in resistivity due to the material of the object to be measured and , the error caused by the contact electromotive force will also cancel out.Here,
Potential detected by measuring depth d of crack 2? ::． ■ is not proportional to the crack depth d as the crack 2 gets deeper, and as shown in Figure 3, ('/Vow) - ood
- A curve with the relationship as shown in (3) is obtained. The index m in the above equation <3> is obtained from the slope of the curve when the relationship between the measured potential difference V and the crack depth d is expressed in logarithm.
従って、被検査体の亀裂深さｄは
ｄ−α（Ｖ Ｖｏｒ）”ＸΔｐｏ／ΔＶＯ−（１／２
）・・・（４）
の関係式を用いてマイクロコンピュータで算出される。Therefore, the crack depth d of the inspected object is d−α(V Vor)”XΔpo/ΔVO−(1/2
)...(4) Calculated by a microcomputer using the relational expression.
なお、αはΔＰ．／Δｖｏの較正により自動的に含んだ
値として求められるので、実際には（２ ｍ ｌとなる
。Note that α is ΔP. /Δvo is automatically included in the calibration, so it is actually (2 ml).
次に上記の如く構成された装置の作用について説明する
。Next, the operation of the apparatus configured as described above will be explained.
亀裂測定に際して設定器２８は掴定モードにセットされ
、又切換スイッチ１７は電位差検出電極１３．１４側に
切換られる。この状態にパルス波発振器２１は第２図に
示すような直流パルス電流を発生する。この直流パルス
電流は定電流回路２２を通して電流電極１１．１２間に
供給される。When measuring a crack, the setting device 28 is set to the gripping mode, and the changeover switch 17 is switched to the potential difference detection electrode 13, 14 side. In this state, the pulse wave oscillator 21 generates a DC pulse current as shown in FIG. This DC pulse current is supplied between the current electrodes 11 and 12 through the constant current circuit 22.
そして、電位差検出電極１３．１４間に現われる電位差
Ｖは切換スイッチ１７を通して測定装置本体２０に送ら
れ、この本体２０の交流増幅器２３で１曽幅されて同期
検波器２４に送られる。この同期検波器２４はパルス波
発振器２１のパルス電１工に同明して各電位差検出電極
１３．１４間の電位差■を取り込む。そして、この電位
差Ｖは平滑回路２５で平滑されてマイクロコンピュータ
２６に送られる。このマイクロコンピュータ２６は′屯
位差Ｖを取り込み、この電位差Ｖから上記第（４）式を
演算して亀裂の深さｄを算出する。Then, the potential difference V appearing between the potential difference detection electrodes 13 and 14 is sent to the measuring device main body 20 through the changeover switch 17, is amplified by 1 in the AC amplifier 23 of this main body 20, and is sent to the synchronous detector 24. This synchronous detector 24 is identical to the pulse generator 1 of the pulse wave oscillator 21 and takes in the potential difference (2) between each potential difference detection electrode 13, 14. This potential difference V is then smoothed by a smoothing circuit 25 and sent to a microcomputer 26. The microcomputer 26 takes in the potential difference V and calculates the crack depth d by calculating the above equation (4) from this potential difference V.
このように上記一実施例においては、金属１の亀裂２を
介して金属表面上に配置された各電流電極１１．１２に
直流パルス電流を供給し、このとき各電位差検出電極１
３．１４間に現れる電位差Ｖから亀裂２の深さｄを算出
するようにしたので、ピーク値が高くかつ平均値の小さ
い直流電流を供給できて深い亀裂２から浅い亀裂２まで
例えば深さ１關未満から５０ｍｍまでの亀裂２を測定で
きる。Thus, in the above embodiment, a DC pulse current is supplied to each current electrode 11, 12 arranged on the metal surface through the crack 2 in the metal 1, and at this time, each potential difference detection electrode 1
Since the depth d of the crack 2 is calculated from the potential difference V that appears between 3.14 and 3.14, it is possible to supply a DC current with a high peak value and a small average value, and from the deep crack 2 to the shallow crack 2, for example, the depth d is 1. It is possible to measure cracks 2 from less than 50mm in diameter.
そして、上記直流パルス電流は平均値が小さいので例え
ば直流パルス電流はピーク電流がＩＡでも０．２Ａ程度
で良く電源が小型にでき、容易に携帯用とすることがで
きる。また、パルス電流としたため、パルス幅が狭いと
き電流は内部まで流れず、表面伝播電流となるので、深
い亀裂でも亀裂深さによって電位差Ｖが大きく変わり、
，精度良く亀裂を７１ｐ１定できる。さらに各電位差検
出電極１３．１４間の電位差を同期検波して取り込んで
いるので、ノイズの影響を大幅に軽減できて安定した深
さＪｌ定ができる。較正は、２対の電位差検出電極１３
〜１６間の各電位差から電位差変化率を求めて行なうの
で、金属１と各電位差検出電極１３〜１６などとの材質
の違いによる接触起電力の影響を受けることがなく、誤
差が発生することがない。Since the DC pulse current has a small average value, for example, even if the peak current of the DC pulse current is IA, it is only about 0.2 A, and the power supply can be made small, and it can be easily made portable. In addition, since the pulse current is used, when the pulse width is narrow, the current does not flow to the inside and becomes a surface propagation current, so even in deep cracks, the potential difference V changes greatly depending on the crack depth.
, 71p1 cracks can be determined with high accuracy. Furthermore, since the potential difference between the respective potential difference detection electrodes 13 and 14 is synchronously detected and captured, the influence of noise can be significantly reduced and stable depth Jl can be determined. Calibration is performed using two pairs of potential difference detection electrodes 13.
Since the rate of change in potential difference is determined from each potential difference between 16 and 16, there is no influence of contact electromotive force due to the difference in material between the metal 1 and each potential difference detection electrode 13 to 16, etc., and errors can occur. do not have.
従って、亀裂深さｄを高精度にｉｌｌｌｌ定できる。Therefore, the crack depth d can be determined with high precision.
なお、本発明は上記一実施例に限定されるものでなくそ
の主旨を逸脱しない範囲で変形してもよい。Note that the present invention is not limited to the above-mentioned embodiment, and may be modified without departing from the spirit thereof.
（発明の効果）
以上詳記したように本発明によれば、深い亀裂から浅い
亀裂までの深さを精度高く測定できる亀裂深さ測定装置
を提供できる。(Effects of the Invention) As described in detail above, according to the present invention, it is possible to provide a crack depth measuring device that can measure the depth from a deep crack to a shallow crack with high accuracy.
第１図乃至第３図は本発明に係わる亀裂深さＤＩ定装置
の一尖施例を説明するための図であって、第１図は構成
図、第２図は直流パルス電流の波形図、第３図は較正時
に用いる定数を説明するための図、第４図は従来装置の
構成図である。
１０・・・ブローブ、１１．１２・・・電流電極、１３
〜１６・・・電位差検出電極、１７・・・切換スイッチ
、２０・・・７Ｎ−１定装置本体、２１・・・パルス波
発振器、２２・・・定電流回路、２３・・・交流増幅器
、２４・・・同期検波器、２５・・・平滑回路、２６・
・・マイクロコンピュータ、２７・・・表示器、２８・
・・設定器。1 to 3 are diagrams for explaining an example of a crack depth DI determining device according to the present invention, in which FIG. 1 is a configuration diagram and FIG. 2 is a waveform diagram of a DC pulse current. , FIG. 3 is a diagram for explaining constants used during calibration, and FIG. 4 is a configuration diagram of a conventional device. 10...Brobe, 11.12...Current electrode, 13
~16... Potential difference detection electrode, 17... Changeover switch, 20... 7N-1 constant device main body, 21... Pulse wave oscillator, 22... Constant current circuit, 23... AC amplifier, 24... Synchronous detector, 25... Smoothing circuit, 26...
...Microcomputer, 27...Display device, 28.
...Setting device.
Claims (2)
置された一対の第１電極と、これら第１電極にパルス状
の直流電流を供給するパルス供給手段と、前記第１電極
の内側で前記亀裂を介して前記被測定体表面上に配置さ
れた一対の第２電極と、これら第２電極間に現れる電位
差から前記亀裂の深さを算出する深さ算出手段とを具備
したことを特徴とする亀裂深さ測定装置。(1) A pair of first electrodes arranged on the surface of the object to be measured through a crack in the object to be measured, a pulse supply means for supplying a pulsed direct current to these first electrodes, and the first electrode a pair of second electrodes disposed on the surface of the object to be measured via the crack inside the device; and depth calculation means for calculating the depth of the crack from the potential difference appearing between the second electrodes. A crack depth measuring device characterized by:
置された一対の第１電極と、これら第１電極にパルス状
の直流電流を供給するパルス供給手段と、前記第１電極
の内側で前記亀裂を介して前記被測定体表面上に配置さ
れた一対の第２電極と、前記第１電極と前記第２電極と
の間で前記亀裂を介して前記被測定体表面上に配置され
た少なくとも一対の第３電極と、前記第２電極及び前記
第３電極に現れる各電位差をそれぞれ受けて電位差変化
に応じた較正値を求める較正手段と、前記第２電極間に
現れる電位差を受けこの電位差と前記較正手段で求めら
れた較正値とにより前記亀裂の深さを算出する深さ算出
手段とを具備したことを特徴とする亀裂深さ測定装置。(2) a pair of first electrodes disposed on the surface of the object to be measured through a crack in the object to be measured, a pulse supply means for supplying a pulsed direct current to these first electrodes, and the first electrode a pair of second electrodes arranged on the surface of the object to be measured through the crack between the first electrode and the second electrode; and a pair of second electrodes arranged on the surface of the object to be measured through the crack between the first electrode and the second electrode at least one pair of third electrodes arranged; a calibration means for receiving each potential difference appearing at the second electrode and the third electrode to obtain a calibration value according to a change in the potential difference; A crack depth measuring device comprising: depth calculation means for calculating the depth of the crack based on the potential difference between the receivers and the calibration value obtained by the calibration means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16013689A JPH0324403A (en) | 1989-06-22 | 1989-06-22 | Apparatus for measuring depth of crack |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16013689A JPH0324403A (en) | 1989-06-22 | 1989-06-22 | Apparatus for measuring depth of crack |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0324403A true JPH0324403A (en) | 1991-02-01 |
Family
ID=15708653
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16013689A Pending JPH0324403A (en) | 1989-06-22 | 1989-06-22 | Apparatus for measuring depth of crack |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0324403A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5217304A (en) * | 1991-08-02 | 1993-06-08 | The United States Of America As Represented By The United States Department Of Energy | Electrical network method for the thermal or structural characterization of a conducting material sample or structure |
| JP2007003436A (en) * | 2005-06-27 | 2007-01-11 | Tokyo Electric Power Co Inc:The | Sensor for crack depth measuring device and crack depth measuring device |
| JP2008083038A (en) * | 2006-08-30 | 2008-04-10 | Atlus:Kk | Method of detecting damage of structure made of conductive material |
| JP2009503467A (en) * | 2005-07-27 | 2009-01-29 | イデント テクノロジー アーゲー | Detection system especially for implementing safety systems |
| CN111006576A (en) * | 2019-12-18 | 2020-04-14 | 戴彬 | Building wall and bridge deck crack monitoring system |
| US10765572B2 (en) | 2014-04-03 | 2020-09-08 | Aplix | Method of assembling at least two units, and a corresponding assembled structure |
-
1989
- 1989-06-22 JP JP16013689A patent/JPH0324403A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5217304A (en) * | 1991-08-02 | 1993-06-08 | The United States Of America As Represented By The United States Department Of Energy | Electrical network method for the thermal or structural characterization of a conducting material sample or structure |
| JP2007003436A (en) * | 2005-06-27 | 2007-01-11 | Tokyo Electric Power Co Inc:The | Sensor for crack depth measuring device and crack depth measuring device |
| JP2009503467A (en) * | 2005-07-27 | 2009-01-29 | イデント テクノロジー アーゲー | Detection system especially for implementing safety systems |
| JP2008083038A (en) * | 2006-08-30 | 2008-04-10 | Atlus:Kk | Method of detecting damage of structure made of conductive material |
| US10765572B2 (en) | 2014-04-03 | 2020-09-08 | Aplix | Method of assembling at least two units, and a corresponding assembled structure |
| CN111006576A (en) * | 2019-12-18 | 2020-04-14 | 戴彬 | Building wall and bridge deck crack monitoring system |
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