JP3599672B2 - Ultrasonic detection method and apparatus and signal processing recording medium - Google Patents

Description

また、よこ波の共振振動数ｆd は（β＝０．５９）

である。
【００５５】
これより、３３〜５６KHz 及びその前後の帯域での成分波では、前記１０２の共振波が大きく生じ、割れ１５からの反射波がこの共振波の中に埋もれることになる。図４の比較波は５２．５KHz を中心周波数とする狭帯域成分波である。この振動数は前述の共振振動数の極めて近傍にあることより、割れ１５からの反射波の存在を確認できなくなる。
【００５６】
一方、図１１は、同一の加算平均波Ｇ1(t)およびＧ2(t)より極めて低周波の狭帯域成分波をそれぞれＧ^〜1(t) およびＧ^〜2(t) として取り出したものである。中心周波数を7.3KHzとしている。この周波数帯であれば前記電柱肉厚ｄに依存する共振妨害波は消滅する。
【００５７】
第１の実施例として、後記［数式３］を用いた解析例を示す。
図１１の波の内、太線は図１の探触子１１，１２の端部から割れ１５までの距離ｌを１０cmとしたものであり、細線は単にこの距離ｌを１５cmとしたものである。本電柱は、図５の計測において、No．１の測点の下側にのみ割れ１５があることを前述した。図１１のNo．１に示す波がこの測点での前述のＧ^〜1(t) 波（太線）、Ｇ^〜2(t) 波（細線）である。No．１に示す前記２っの波のみが、その振幅及び位相が大きく変動し、No．２，No．３に示す前記２っの波は振幅及び位相とも、殆ど変化していない。
【００５８】
前述の図１の１０２の妨害波として非共振波も存在する。図１１のNo．１〜No．３の波で最初に大きな振幅で励起している波が、この１０２の非共振妨害波である。
【００５９】
これにより、図１１で太線Ｇ^〜1(t) 波と、細線Ｇ^〜2(t) の波より、［数式３］で示す波を作成すれば、前記非共振妨害波が除去され、若しひび割れ１５があれば、ひび割れ１５からの反射波のみが求められる。
【００６０】
［数式３］ Ｇ^〜2(t) −Ｇ^〜1(t)
図１２で、No．１のＧ^〜2(t) −Ｇ^〜1(t) 波のみでひび割れ１５からの反射波が確認できる。
【００６１】
前述の図１１、１２を得るための分析で用いたＧ1(t)，Ｇ2(t)波（加算平均波）は、前述の図１０（ａ，ｂ）に示す最適な波ではない。単に、ひび割れ１５から、探触子１１，１２の端部までの距離ｌを、Ｇ^〜1(t) 波（太線）で１０cmとし、Ｇ^〜2(t) 波（細線）で１５cmとしたものである。図９（ａ，ｂ）の如く、それぞれひび割れ１５からの反射波強度が最も小さく、また最も大きくなる様に、探触子１１，１２の位置を決めたものではない。
【００６２】
以上により、前述の最適なる探触子位置の選定法（位置の評定）について以降に示す。
［１］ Ｇ1(t)波の収録
１）．まず、電柱１４の地中部のグランドライン１７の近くで、図１に示す如く、探触子１１，１２を配置し、試計測を行う。３２回程度の加算平均波1Ｇ1(t) を収録し、２０KHz 付近を中心周波数とする狭帯域成分波1Ｇ^〜1(t)を作成し、 超音波探知装置２０の表示装置２３の計測画面上に、図１３に示す如く、1Ｇ^〜1(t)波を表示する。
【００６３】
２）．探触子１１，１２の位置を柱軸方向に沿って、下側又は上側へΔｌ＝５mm、または、１０mm程度の間隔で移動する。上記移動が終了し探触子１１，１２の位置を固定した段階で再度試計測を行い、３２回程度の加算平均波2Ｇ1(t) を収録し、前述と同様に２０KHz 付近を中心周波数とする狭帯域成分波2Ｇ^〜1(t)を作成し、超音波探知装置２０の表示装置２３の計測画面上に表示されている1Ｇ^〜1(t) 波の上に、前述の2Ｇ^〜1(t)波をリアルタイムに重ね描きする。
【００６４】
３）．上述した２）の試計測を繰り返して、その都度得られる前述の試計測波iＧ^〜1(t)を前述の1Ｇ^〜1(t)の上にリアルタイムに重ね描きしていくと、ひび割れ１５がある場合、1Ｇ^〜1(t)とiＧ^〜1(t)との波の形状が探触子１１，１２の位置の変動に伴い大きく変動する。（なお、添字のi は移動回数）。
【００６５】
その結果、図１４の点線で示すiＧ^〜1(t)波が得られる。iＧ^〜1(t)の波で、波の後方に大きな振幅の生じない波がある。この時の探触子１１，１２の位置で波を収録する。勿論、1Ｇ1(t) 波は、計測環境からの外乱の除去のために、適切なる加算平均化回数を指定した加算平均波である。
【００６６】
４）．前述の２）の計測を繰り返し、その都度得られる前述の試計測波1Ｇ1(t)の２０KHz 付近を中心周波数とする狭帯域成分波iＧ^〜1(t)を、前述の1Ｇ^〜1(t)の上に重ね描きしていくと、ひび割れ１５がない場合、1Ｇ^〜1(t)とiＧ^〜1(t)との形状及び位相は殆ど変化しない。この場合、適当なi で探触子１１，１２の位置を決めてＧ1(t)なる加算平均波を収録すればよい。
［２］ Ｇ2(t)波の収録
１）．前述のごとく収録された加算平均波Ｇ1(t)より、２０KHz を中心周波数とする狭帯域成分波Ｇ^〜1(t) を作成し、超音波探知装置２０の表示装置２３の計測画面上に、前述のＧ^〜1(t) 波を表示する。図１４の点線波形がこのＧ^〜1(t) に相当する。
【００６７】
２）．前述のＧ1(t)波の収録位置は、［１］の３）および４）でのＧ1(t)波の収録で確定している。そしてＧ2(t)波の収録開始時には、前述の確定位置に探触子１１，１２が配置されている。この位置を始点に、柱軸に沿って下側又は上側へΔｌ＝５mm、または、１０mm程度の間隔で探触子位置を移動させ、その都度iＧ^〜2(t)波を試計測する。iＧ^〜2(t)波は３２回程度の加算平均波である。添字i は探触子１１，１２の移動回数である。この測点でひび割れ１５があれば、この試計測の中で、図１４の実線波形の如きiＧ^〜2(t)波の表示を確認できる。
【００６８】
勿論、iＧ^〜2(t)波は、前記の如く、２０KHz 付近を中心周波数としてiＧ2(t) 波より取り出した狭帯域成分波である。前述の点線波形Ｇ^〜1(t) と実線波形iＧ^〜2(t) を超音波探知装置２０の表示装置３４の計測画面上でリアルタイムに表示することで比較し、図１４に示す如く、Ｇ^〜1(t) とiＧ2(t) との波の形状が大きく変動する探触子１１，１２の位置を前述の如く探し、この探触子位置でＧ2(t)波を収録する。勿論、Ｇ2(t)波は、計測環境からの外乱の除去のために適切なる加算平均化回数を指定した加算平均波である。
【００６９】
３）．前述の２）に示したＧ2(t)波の収録で、その測点でひび割れ１５が存在しない場合、前述のＧ^〜1(t) 波と1Ｇ^〜2(t)波との形状及び位相は殆ど変化しない。この場合、適当なi で探触子位置を決め、Ｇ2(t)なる加算平均波を収録すればよい。
【００７０】
以上説明したごとく、２０KHz 付近の中心周波数の成分波を用いて、図９（ａ）に示すひび割れ１５からのたて波反射波強度が小さくなる加算平均波Ｇ1(t)を計測する方法と、図９（ｂ）に示すひび割れ１５からのたて波反射波強度が大きくなる加算平均波Ｇ2(t)を計測する方法を示した。
【００７１】
なお、Ｇ1(t)の計測を図９（ｂ）の場合にし、Ｇ2(t)の計測を図９（ａ）の場合にしても、一向に構わない。
【００７２】
ところで、前述のＧ^〜1(t) ，Ｇ^〜2(t) の取り出しで、２０KHz 付近の中心周波数を採用した理由を示しておく。日本国内で一般的な電柱１４の肉厚ｄは４０^〜５０mm程度である。これより図１の１０２に示す妨害波の共振振動数成分の下限は、前述の［数式２］に基づいて算出すると、
たて波で ｆd ＝４５００m/sec／２×５０mm＝４５KHz ．
よこ波で ０．５９ｆd ＝ほぼ２４KHz ．
程度である。これより上述の共振振動数を避けて、２０KHz とした。なお、４５KHz 以上の高周波を中心周波数としなかった理由は、散乱波など他の妨害波による共振現象による悪い環境を避けるためであった。
【００７３】
前述の［１］．［２］よるＧ1(t)およびＧ2(t)の波の取得によるひび割れ測定の方法を第２の実施例として、以降に示す。
【００７４】
図１の計測において、電柱１４の外径３０cm、肉厚ｄ＝５０cm、距離ｌ＝２０cm（ひび割れ１５から探触子１１，１２の斜角治具１３の端部までの距離は１５cm程度である）の場合のひび割れ測定である。
【００７５】
探触子１１，１２間の距離ａは１５０mmである。２０KHz 付近を中心周波数とするＧ^〜1(t)と1Ｇ^〜2(t) のリアルタイム表示例を図１５に示す。細線波がＧ^〜1(t) であり、太線がiＧ^〜2(t)である。波形後方で２っの波の形状が大きく変化している。この iの位置でＧ2(t)を収録した。Ｇ1(t)，Ｇ2(t)波共５００回の加算平均波である。
【００７６】
本実施例は前述したリアルタイム計測で、図９（ａ）の如きひび割れ反射経路でＧ1(t)を、図９（ｂ）の如きひび割れ反射経路でＧ2(t)を計測していることより、Ｇ2(t)波に含まれる割れ１５からの反射波強度が大きなものとなっている。これより前述の第１の測定例のように極く低周波でなくとも、高周波成分波でひび割れ１５からの反射波を取出すことが可能である。
【００７７】
当然、高周波成分でひび割れ１５からの反射波を取出せれば、ひび割れ１５と、探触子１１，１２間の距離をより高精度に測定できる。図１６に示すNo．１の２っの波はこの場合の成分波である。９１．６KHz を中心周波数とする狭帯域波である。太線がＧ^〜1(t) 波、細線がＧ^〜2(t) 波である。No．２の２っの波は割れ１５がない場合の同様の比較波形である。
【００７８】
Ｇ^〜1(t) −Ｇ^〜2(t)
なる減算を行った結果を図１７に示す。No．１の減算波でカーソル位置ｔ0 より大きな振幅の波の起生が確認できる。この波の起生時刻は70μ秒より、本実施例でのコンクリートの音速cＧp＝４５００m/sec 、及びａ＝１５０mm、探触子径５５mmを用いて、探触子１１，１２とひび割れ１５までの距離ｌ1 を算出すると、 ｌ1 ＝［（７０×４．５／２）^２−（（１５０−５５）／２）^２］^1/2 ＝ほぼ１５０mm
となる。この値は探触子１１，１２の端部とひび割れ１５までの距離の実値１５０mmと一致する。
【００７９】
一方、図１８は、図１の１０２の電柱肉厚ｄに依存する妨害波が共振現象を起す周波数帯でのＧ^〜1(t)−Ｇ^〜2(t)を示したものである。前述した理由で妨害波が残存し、ひび割れ１５からの反射波の起生とその時刻を確認できない。
【００８０】
前述のＧ^〜1(t) ，Ｇ^〜2(t) において、最初に生ずる大きな振幅の波は、図１の１０２の妨害波であった。
【００８１】
前述の［数式１］で示す周波数ｆ0 より低周波で、かつ［数式２］で示す周波数帯以外の周波数を中心周波数とする狭帯域成分波Ｇ^〜1(t)およびＧ^〜2(t)では、殆どの場合、その波の形、強度は略同一であり、位相ずれも微小である。前述の実施例１及び２は、この様な場合の測定例で、ひび割れ１５からの反射波を、［数式３］を用い、
Ｇ^〜1(t) −Ｇ^〜2(t)
として求めるものであった。
【００８２】
ところで、図１９に示す如く、電柱１４のコンクリート内には柱軸方向に主筋１９ａが、その円周方向には螺旋状フープ筋１９ｂがそれぞれ配されている。
【００８３】
一方、前述のＧ1(t)，Ｇ2(t)波の収録に当って、探触子１１，１２の移動方向は柱軸方向であった。これより、探触子１１，１２の位置によっては、この螺旋状フープ筋１９ｂからの反射波を受信する場合もあれば、受信しない場合もある。
【００８４】
この波は、前述の１０２の妨害波と重畳して起生する。また、図２０に示す如く、探触子１１，１２の配置の近傍に縦方向のフェアクラック５０１等がある場合、図示する如く、探触子１１，１２の位置によっては、１０２の妨害波がこのフェアクラック５０１で遮断されることもある。
【００８５】
この様な場合、前述のＧ^〜1(t)，Ｇ^〜2(t)波の最初に生ずる大きな振幅の波１０２及び螺旋フープ筋１９ｂ等から反射波の重畳波は、その形状及び強度に相違が生じ、かつ位相ずれも生じてくる。
【００８６】
この問題に対処するために、
１）．前述のＧ^〜1(t) ，Ｇ^〜2(t) において、
電柱１４の肉厚ｄとコンクリート音速cＶpで表される１０２の探知妨害波の最初の起生時刻ｔ0 ＝２ｄ／cＶp以降に生ずるＧ^〜1(t) ，Ｇ^〜2(t) の１番目の、及び２番目の、及び３番目の、及び４番目のいずれかの波山及び波谷の時刻ｔw で、Ｇ^〜1(t) ，Ｇ^〜2(t) のいずれか一方の波を時間Δｔだけ前後にずらすことで合致させ、Ｇ^〜1(t) ，Ｇ^〜2(t) の換わりに、それぞれ時間軸が相互に時間Δｔだけ移動した補正波Ｈ1(t) およびＨ2(t) を求め［数式４］に示す波を作成する。
【００８７】
［数式４］ Ｈ1(t)−Ｈ2(t) または、 Ｈ2(t)−Ｈ1(t)
２）．前述のＧ^〜1(t) ，Ｇ^〜2(t) において、
前述の探知妨害波の最初の起生時刻ｔ0 ＝２ｄ／cＶp以降に生ずるＧ^〜1(t) ，Ｇ^〜2(t) の１番目の、及び２番目の、及び３番目の、及び４番目のいずれかの波山及び波谷の時刻ｔw で、Ｇ^〜1(t) ，Ｇ^〜2(t) のいずれか一方の波を時間Δｔだけ前後にずらすことで合致させ、Ｇ^〜1(t) ，Ｇ^〜2(t) の換わりに、それぞれ時間軸が相互に時間Δｔだけ移動した補正波Ｈ1(t) およびＨ2(t) を求め、
前述の時刻ｔw におけるＧ^〜1(t) ，Ｇ^〜2(t) の振幅値の絶対値をそれぞれＷ1 ，Ｗ2 と定義し、［数式５］に示す波を作成する。
【００８８】
［数式５］ Ｗ2 ／Ｗ1 Ｈ1(t)−Ｈ2(t)
または Ｗ1 ／Ｗ2 Ｈ2(t)−Ｈ1(t)
なお、Ｗ2 ／Ｗ1 Ｈ1(t)、Ｗ1 ／Ｗ2 Ｈ2(t)は、修正補正波と称することができる。
【００８９】
前述の［数式４］及び［数式５］で作成される波を用いれば、前述の螺旋状フープ筋１９ｂからの反射波等がＧ1(t)，Ｇ2(t)波の中に含まれる場合であっても、また探触子１１，１２の配置の近傍にフェアクラック５０１等がある場合でもひび割れ１５からの反射波の起生を特定できる。
【００９０】
実施例３として、実施例２で示した電柱外径３０cm、肉厚ｄ＝５０mm、ひび割れ１５から斜角治具１３の端部までの距離１５cm、発信及び受信探触子１１，１２の間隔ａを１５０mmとした時のひび割れ計測に、前述の［数式４］及び［数式５］を適用する。
【００９１】
図１６は、９１．６KHz を中心周波数とする狭帯域成分波であるＧ^〜1(t) とＧ^〜2(t) をそれぞれ太線及び細線で示したものであった。No．１の測点で、探触子１１，１２の端部から１５cm下側に割れ１５があり、No．２の測点では割れのない測定であった。図示するカーソル位置ｔw ＝４１．９μ秒で［数式４］を適用した結果を図２１に、［数式５］を適用した結果を図２２に示す。［数式４］及び［数式５］を適用した相方の結果共、No．１の測点での割れ１５からの反射波を明敏に抽出している。
【００９２】
なお、実施例１、２、３で示した各波は、図４、７、１０、１１、１３、１４、１５、１６を除き、実際の波をｆ(t) と表現したとき、ｆ^２(t)、あるいはｆ^３(t)で表示し、ピーク強張している。
【００９３】
本発明は、電柱、よう壁の地中部及び張紙防止帯の目視し得ぬ位置にあるひび割れの探知のみならず、図２３に示すように、電柱１３のその根入深さｌ3 などの探知に、そのまま適用できる。電柱下側端部からの反射は、割れからの反射と工学的には全く同種のものだからである。
【００９４】
以上は、この発明の一実施例を説明したが、この発明は上述の実施例の構成のみに限定されるものではなく、多くの実施の形態を備える。
【図面の簡単な説明】
【図１】超音波探知の縦断面および横断面で示す模式図。
【図２】超音波探知装置の構成ブロック図。
【図３】探触子の配置説明図。
【図４】探知波の波形図。
【図５】探知時の探触子の配置を示す横断面の説明図。
【図６】広帯域超音波の波形図。
【図７】時系列波の波形図。
【図８】狭帯域成分波のスペクトル形状を示す波形図。
【図９】反射波の状態を縦断面で示す模式図。
【図１０】成分波取出しを模式的に示した波形図。
【図１１】加算平均波から取出した低周波狭帯域成分波の波形図。
【図１２】数式３で作成される探知波の波形図。
【図１３】波1Ｇ^〜1(t)の波形図。
【図１４】波1Ｇ^〜1(t)と試計測波iＧ^〜1(t)とを重ねた波形図。
【図１５】波Ｇ^〜1(t) と1Ｇ^〜2(t)とを重ねた波形図。
【図１６】高周波成分の波形図。
【図１７】減算処理を行った波形図。
【図１８】妨害波が共振現象を起す周波数帯で減算処理を行った波形図。
【図１９】鉄筋を備えた電柱の縦断面図。
【図２０】フェアクラックを持つ電柱の横断面図。
【図２１】数式４で作成される探知波の波形図。
【図２２】数式５で作成される探知波の波形図。
【図２３】他の例の電柱の縦断面図。
【符号の説明】
１１…発信探触子
１２…受信探触子
１３…斜角治具
１４…電柱
１５…割れ
２０…超音波探知装置
２１…パルス発生器
２２…解析装置
２２ｆ…ハードディスク
２３…表示装置
２５…ＣＤ[0001]
TECHNICAL FIELD OF THE INVENTION
This invention uses an ultrasonic wave, for example, an ultrasonic detection method of detecting the presence and location of a crack in an invisible part such as a reinforced concrete electric pole or the underground part of a yoke wall from the ground, and an ultrasonic detection method thereof. The present invention relates to an apparatus and a signal processing recording medium.
[0002]
[Prior art]
For example, assuming that the inside of a concrete material is detected using ultrasonic waves, the following factors have made it impossible to detect the inside in most cases. If you show the cause,
-Ultrasonic waves cause a large scattering phenomenon due to the presence of a large amount of coarse aggregate and bubbles in the concrete.
The detection phenomenon of a large power is generated by the scattering phenomenon, and the detection target wave is buried in the interference wave.
・ Deterioration of the detected object due to aging.
-Countless large and small cracks on the scanning surface.
・ The shape of the object to be detected.
・ Electric noise and disturbance of large power are mixed into the received wave.
And so on.
[0003]
On the other hand, recently, a macroscopic detection theory has been established as a methodology capable of detecting the inside of concrete with high accuracy by eliminating the problems caused by the above factors, and an ultrasonic detection device and an ultrasonic method based on this have appeared. ing.
[0004]
However, it is difficult to detect underground cracks such as electric poles from the surface of the electric poles with the above-mentioned detection apparatus. In the detection under such a theme, the intensity of the reflected wave from the crack is weak, and the reflected wave is buried in the interfering wave whose power is extremely large for the reasons described in 2) and 5) above. It is because.
[0005]
[Problems to be solved by the invention]
1A and 1B, a pair of a transmission probe 11 for transmitting a broadband ultrasonic wave and a reception probe 12 for receiving a reflected wave of the transmitted ultrasonic wave is fixed to a bevel jig 13. An example in which the electric pole 14 made of reinforced concrete is arranged in parallel with the pillar axis is shown.
[0006]
In the case of this example, the vertical ultrasonic wave transmitted toward the center of the electric pole 14 at an angle θ1 through the bevel jig 13 is input into the concrete of the electric pole 14 at an angle θ2 shown in accordance with Huygens' principle. Is done.
[0007]
This input ultrasonic wave is repeatedly reflected on the front surface of the telephone pole 14 and the back surface relating to the wall thickness thereof, and reaches a crack 15 in the underground portion. As shown in the figure, the reflection is repeated in the same direction as described above in the arrangement direction of the probes 11 and 12. Come back. The following problems arise with such transmission.
[0008]
1) The ultrasonic wave (detection target wave) of the above-mentioned reflection path is an attenuation phenomenon caused by the existence of scattering attenuation peculiar to the concrete material of the electric pole 14 and the repetition of many reflections on the front and rear surfaces of the electric pole 14 with respect to the wall thickness. Strength decreases.
[0009]
2) The above-described intensity decrease increases at an accelerated rate as the frequency of the high-frequency ultrasonic wave increases.
[0010]
3) The detection target wave that returns in the arrangement direction of the probes 11 and 12 is not received by the reception probe 12 in the schematic diagram illustrated in FIG. Thus, the reception intensity of the detection target wave greatly changes depending on the position where the transmitting and receiving probes 11 and 12 are arranged (in other words, the positions of the probes 11 and 12 are changed in the column axis direction). Then, the positions of the probes 11, 12 at which the intensity of the detection target wave becomes larger can be selected.)
[0011]
4) As shown in FIG. 1 (a), in the case of a material such as concrete, which has a large scattering phenomenon even when ultrasonic waves 101 are input in an oblique direction at an angle θ2, a super-power having a relatively large power transmitted in the horizontal direction is used. A sound wave 102 is present. This ultrasonic wave 102 generates an interfering wave having a greater power than the detection target wave. FIG. 1A schematically shows the transmission state of the ultrasonic waves 102 within the thickness of the utility pole 14. This is a so-called overlapping reflection. Such a wave causes a resonance phenomenon, and its power becomes large. In addition, the strength greatly changes due to subtle changes in the state of adhesion of the couplant between the surface of the electric pole 14 and the probe and the jig, the state of the electric pole surface, the state of pressing the probe, and the like.
[0012]
Unless the above-mentioned problems 1, 2, 3, and 4 are addressed, cracks 15 in the underground portion of the utility pole 14, cracks in the backing prevention band 16 of the utility pole 14 (see FIG. 1A), and It is impossible to detect cracks in the underground part of the wall.
[0013]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and detects a crack such as a crack in an underground portion of a utility pole, a crack in an underground portion of a wall, and a crack that has occurred in an invisible place in a strapping prevention band. It is an object of the present invention to provide an ultrasonic detection method, an apparatus thereof, and a signal processing recording medium that can be performed with high accuracy.
[0014]
[Means for Solving the Problems]
The present invention is an ultrasonic detection method or an ultrasonic detection method for receiving a reflected wave of an ultrasonic wave transmitted in a diagonal direction from the surface of a detection target object to a detection direction side and detecting a state inside the detection target object, A first detection position for receiving and detecting the transmitted reflected wave of the ultrasonic wave with respect to the detection target object, and moving the predetermined amount from the first detection position to the far side in the detection direction to perform the first detection The averaged waves G1 (t), G2 (t) are evaluated by evaluating the second detection position to be detected in the same manner as the position, and adding the received waves obtained for each ultrasonic output at each position to obtain an average value. Is calculated from each of these averaged waves G1 (t) and G2 (t) with a narrow band component wave G centered on a predetermined frequency.^~1 (t), G^~2 (t), and these narrowband component waves G^~1 (t), G^~It is an ultrasonic detection method or apparatus for detecting a form inside a detected object by comparing the waveform shapes of 2 (t).
[0015]
That is, two narrow-band component waves G^~1 (t), G^~When 2 (t) is compared and a clear difference between the two waveform shapes can be determined, it is possible to recognize a morphological change inside the detected object.
[0016]
In a preferred embodiment, the narrow-band component wave G^~1 (t), G^~2 (t)
G^~1 (t) -G^~2 (t) or G^~2 (t) -G^~1 (t)
, A detection wave is calculated, and the shape inside the detection target object can be detected by the waveform shape of the detection wave.
[0017]
In a preferred embodiment, when a waveform having a large amplitude is generated in the detection wave, an occurrence time tl of the waveform is calculated, and the occurrence time tl and the ultrasonic wave propagation speed cVp of the detected object are calculated. The position of the morphological change can be calculated based on
[0018]
In one preferred embodiment, the narrowband component wave G^~1 (t), G^~When the onset time t0 of the large amplitude wave generated at the beginning of 2 (t) is the thickness d of the detected object and its ultrasonic propagation velocity cVp,
t0 = 2d / cVp
And the narrow band component wave G occurring after the time of occurrence t0.^~1 (t), G^~2 (t) at the time tw of any one of the first to plural wave peaks or troughs, the two narrowband component waves G^~1 (t), G^~Correction waves H1 (t) and H2 (t) are generated by shifting one of the waves of 2 (t) forward and backward of the time axis by Δt time to match the waveforms, and these correction waves H1 (t) and H2 By comparing the waveform shapes in (t), the morphology inside the detected object can be detected.
[0019]
As one of preferred embodiments, the correction waves H1 (t) and H2 (t) are
H1 (t) -H2 (t) or H2 (t) -H1 (t)
, A detection wave is calculated, and the shape inside the detection target object can be detected by the waveform shape of the detection wave.
[0020]
As one preferred embodiment, the narrow-band component wave G at the time tw of the wave crest or wave trough is provided.^~1 (t), G^~The absolute values W1 and W2 of 2 (t) are calculated, and one of the correction waves H1 (t) and H2 (t) is compared with the other by the quotient W1 / W2 or W2 / W1 of these absolute values W1 and W2. So that both waves become corresponding waves, one of the corrected waves W2 / W1 · H1 (t) and W1 / W2 · H2 (t) and the other corrected waves H1 (t) and H2 (t). To
W2 / W1 · H1 (t) -H2 (t) or W1 / W2 · H2 (t) -H1 (t)
, A detection wave is calculated, and the shape inside the detection target object can be detected by the waveform shape of the detection wave.
[0021]
As one of preferred embodiments, the thickness d of the detected object, the ultrasonic wave propagation velocity cVp of the object, the diameter φ of the probe,Person in chargeNumber β,coefficient(Correction value)Based on α, the first frequency f0 at which the intensity of the disturbance wave propagating from the probe in the transverse direction to the detection direction is reduced, and the resonance disturbance frequency fd
f0 = αcVp / φfd = βcVp / 2d
And the narrowband component wave G^~1 (t), G^~2 (t) is defined as the first frequencyf 0Lower frequencyToIs selected, and the above-mentioned resonance frequency fd is removed to remove the narrow band component wave G.^~1 (t), G^~2 (t) can be created.
[0022]
As a preferred embodiment, the arithmetic means for performing the arithmetic processing can be constituted by a personal computer, and a computer-readable disk system such as a CD, HD, or FD, or another computer-readable signal processing program for performing the arithmetic processing. It can be recorded on a recording medium.
[0023]
As one of preferred embodiments, the transmitting probe for transmitting the ultrasonic wave of the ultrasonic generating means and the receiving probe for receiving the reflected wave may be separate bodies or may be of an integrated type. Further, when the transmitting probe and the receiving probe are formed separately, these detection positions may be arranged left and right in parallel, or may be arranged vertically in series. Further, the movement for evaluating the position can be performed by moving both at the same time or by moving one of them.
[0024]
【The invention's effect】
According to the present invention, the intensity of the detection target wave can be increased by removing various interference waves, and the internal state and the position of the detected object can be detected with high accuracy.
[0025]
【Example】
An embodiment of the present invention will be described below with reference to the drawings.
[0026]
The drawings show an ultrasonic detection method and its device, and FIG. 1 shows a schematic diagram of the ultrasonic detection method as described above.
[0027]
FIG. 2 shows an ultrasonic detection device 20, which includes a pulse generator 21, an analysis device 22, and a display device 23.
[0028]
The above-described pulse generator 21 is generated by a pulse generation circuit 21a that generates a pulse of a broadband frequency, a pulse interval change circuit 21b that changes an interval between the generated pulses to a predetermined interval, and a pulse generation circuit 21a. It is formed by a pulse drive circuit 21c that outputs pulses at pulse intervals set by the pulse interval change circuit 21b.
[0029]
The broadband ultrasonic wave of the pulse output from the pulse generator 21 is transmitted from the transmission probe 11 to the telephone pole 14, and the reflected wave is received by the reception probe 12 and amplified by the external amplifier 24. The data is input to the analysis device 22.
[0030]
The above-described analyzer 22 includes an amplifier circuit 22a for amplifying a signal, a filter circuit 22b formed of a filter such as a low-pass filter or a high-pass filter for removing unnecessary signals, an A / D converter 22c, A gate array 22d for adding a received wave to obtain an average value, a CPU 22e for performing drive control and arithmetic processing of each of these circuit devices, and a hard disk 22f for storing programs necessary for performing analysis processing and arithmetic processing It is formed by.
[0031]
The above-described program is recorded on a CD (compact disk) 24, and is installed from the CD 24 to a hard disk 22f and stored.
[0032]
The CPU 22e and the hard disk 22f can be constituted by a well-known personal computer.
[0033]
Further, the display device 23 may be constituted by a liquid crystal or a cathode ray tube.
[0034]
A measurement diagram for detecting cracks 15 and the like in the underground portion of the utility pole 14 is shown in FIG. 1 by the two probe method using the transmission probe 11 and the reception probe 12, but the measurement is limited to this arrangement method. Not something. FIGS. 3A and 3B show two arrangement methods used in the measurement. Further, the measurement as shown in FIG. 3C may be performed by using a probe that is common to transmission and reception.
[0035]
In the probe parallel arrangement and the series arrangement shown in FIGS. 3A and 3B, since the ultrasonic wave input direction to the concrete is inclined only as shown in FIG. Raw is much smaller for series placement measurements than for parallel placement measurements. In the one-probe measurement shown in FIG. 3C, a dead zone due to its mechanical and electrical characteristics is generated in front of the received wave. Although there is a difference, it is equivalent to the case of the parallel arrangement in FIG. 3 (a, b). Hereinafter, the details of the ultrasonic detection apparatus and the detection method will be described by using the probe parallel arrangement measurement of FIG. 3A and measuring the underground crack of the utility pole 14 as an example.
[0036]
FIG. 4 shows the measurement results when the outer diameter φ = 30 cm, the wall thickness d = 4 cm, the distance l between the probe and the crack was 10 cm, and the diameter of the probe diameter was 55 mm in the electric pole cracking model shown in FIG. It is an example. FIG. 8 has a center frequency of 52.5 KHz from a wave obtained by continuously transmitting ultrasonic waves 1000 times at intervals of 5 seconds and averaging automatically the received waves by the gate array 22 d provided in the analyzer 22. The narrow band component wave having the spectrum shape shown in FIG.
[0037]
Also, three measurement waves are shown side by side. As shown in FIG. 5, there is a crack only below the measurement point of No. 1 and No. One of the measurement examples in which there is no crack below No. 3 is a broadband ultrasonic wave shown in FIG. The time series wave (FIG. 7) has a maximum spectrum value of 360 KHz and contains a large amount of components in the low frequency region. Each measurement wave shows two lines, a thick line and a thin line. The bold line wave is obtained by setting the value of the distance 1 to 10 cm in the measurement diagram of FIG. 1. The thin line wave is obtained by setting the value of the distance 1 to 15 cm.
[0038]
As can be seen from FIG. 4, it is impossible to judge that there is a crack under the measurement of No. 1.
[0039]
The reason for this is that the following common problems occur in the probe parallel arrangement and serial arrangement measurement of FIG. 3A and FIG. 3C, and in the measurement of the transmission and reception probe shared in FIG. 3C. It is.
[0040]
1). A wave 103 transmitted between the probes 11 and 12 on the concrete surface of FIG. 1 is generated as an interference wave for crack detection. The power is very large.
[0041]
2). The wave of 102 which is reflected by the thickness of the telephone pole 14 in FIG. This resonance wave is a strong interference wave. Due to the resonance wave, the difference in the fine positions of the probes 11, 12 and the difference in the application of the couplant between the probes 11, 12 and the angled jig 13 and the surface of the utility pole 14, and the difference in the pressing force. The state of occurrence of the resonance wave fluctuates greatly.
[0042]
3). As shown in FIG. 9, the intensity of the reflected wave from the crack included in the received wave greatly varies depending on the installation positions of the probes 11, 12. FIG. 9A shows a state in which the reflected wave is not received and the reflected wave generated by the mode conversion is received, and FIG. 9B is a state in which the reflected wave is received. As described above, depending on the installation positions of the probes 11 and 12, a physical phenomenon that the vertical wave reflection from the crack 15 becomes large at another position, or the intensity of the reflected wave from the crack 15 is extremely small. Physical phenomena such as becoming occur.
[0043]
Unless the problems 1) to 3) are addressed, it is difficult to obtain a reflected wave from the crack 15.
The solution is as follows.
[0044]
According to the macroscopic detection theory, the interference wave shown in the above 1) is a frequency band near the f0 value calculated by [Equation 1] from the diameter φ of the probes 11 and 12 and the concrete sound velocity (propagation velocity) cVp based on the macroscopic detection theory. , Its strength is reduced. Waveform analysis using this phenomenon should be performed.
[0045]
[Equation 1] f0 = αcVp / φ
Here, α is a correction coefficient determined in a measurement experiment.
[0046]
For the above problem 2), the resonance frequency fd of the double reflection wave 102 in FIG. 1 is calculated as in [Equation 2] using the thickness d of the utility pole 13 and the concrete sound speed cVp.
[0047]
[Equation 2] fd = βcVp / 2d
Where β = 1 and 0.59
0.59 is the speed ratio between the concrete wave and the vertical wave.
[0048]
By performing the above calculation, if the narrow-band component wave excluding fd and the frequency spectrum before and after fd is extracted from the averaging wave, the adverse effect of the resonance phenomenon can be avoided.
The following problem 3) will be dealt with as follows.
[0049]
As shown in FIG. 9, the intensity of the reflected wave from the crack 15 of the utility pole 14 included in the averaging wave at the position (a) and the averaging wave at the position (b) greatly differ. On the other hand, the interfering waves 102 and 103 at the position (a) do not significantly change in shape and intensity from the interfering waves at the position (b). Even if the shape and strength slightly change due to the excessive amount of the couplant, the amount of the change decreases as the extraction of the component wave is swept in the low frequency direction. FIG. 10 schematically shows this situation.
[0050]
FIG. 10A shows the interference wave 401 corresponding to the measurement of FIG. 9A and the reflected wave 403 from the crack 15.
FIG. 10B shows the interference wave 402 corresponding to the measurement of FIG. 9B and the reflected wave 404 from the crack 15.
[0051]
Now, let the superimposed wave of 401 and 403 be G^~1 (t), and the superimposed wave of 402 and 404 is G^~Assuming that 2 (t), the interference waves 401 and 402 have almost the same shape as described above.
G^~2 (t) -G^~1 (t)
The wave shown in FIG. 10C becomes as shown in FIG. Although not shown in the figure,
G^~1 (t) -G^~2 (t)
However, the peaks and valleys of the waves only reverse.
[0052]
In FIG. 9, if the positions of the distances l1 and l2 are properly selected, the value of tl in FIG. 10C is the time of occurrence of the reflected wave from the crack 15 in the measurement of FIG. 9B.
The above-mentioned appropriateness means that in the measurement of FIG. 9A, a composite wave G1 (t) (that is, an attenuation wave) of 401 and 403 as shown in FIG. 10A is obtained, and FIG. In the measurement of (a), a probe position where a large amplitude wave is generated behind the wave in the composite wave of 402 and 404 as shown in FIG. 10 (b) is searched, and the averaging wave G2 (t) is measured at this position. It is.
[0053]
Now, in the measurement shown in FIG. 5, a narrow band component wave of 52.5 KHz is obtained from each of the above-mentioned waves G1 (t) and G2 (t), which is obtained as an averaging wave 1000 times at each measurement point, and is compared. In FIG. The reason why a reflected wave from the lower side of the measurement point 1 cannot be found will be described in comparison with the above-mentioned problem.
[0054]
This utility pole model has an outer diameter of 30 cm and a thickness d of 40 mm. Thus, the vertical resonance frequency fd of the interfering wave 102 shown in FIG. 1 is given by the above-mentioned [Equation 2] fd = βcVp / 2d (β = 1) when the propagation velocity cVp is 4500 m / sec.

The resonance frequency fd of the transverse wave is (β = 0.59)

It is.
[0055]
As a result, in the component wave in the frequency band of 33 to 56 KHz and before and after that, the resonance wave 102 is generated largely, and the reflection wave from the crack 15 is buried in the resonance wave. The comparison wave in FIG. 4 is a narrow band component wave having a center frequency of 52.5 KHz. Since this frequency is very close to the above-mentioned resonance frequency, the presence of the reflected wave from the crack 15 cannot be confirmed.
[0056]
On the other hand, FIG. 11 shows that the narrow-band component waves of much lower frequency than the same averaged waves G1 (t) and G2 (t) are^~1 (t) and G^~2 (t). The center frequency is 7.3KHz. In this frequency band, the resonance interference wave dependent on the pole thickness d disappears.
[0057]
As a first embodiment, an analysis example using the following [Equation 3] will be described.
In the wave of FIG. 11, the thick line indicates that the distance 1 from the ends of the probes 11, 12 in FIG. 1 to the crack 15 is 10 cm, and the thin line indicates that the distance 1 is simply 15 cm. In the measurement of FIG. As described above, the crack 15 exists only below the measurement point 1. No. of FIG. The wave shown in FIG.^~1 (t) wave (thick line), G^~It is a 2 (t) wave (thin line). No. Only the two waves shown in FIG. 1 greatly fluctuated in amplitude and phase. 2, No. The two waves shown in FIG. 3 hardly change in both amplitude and phase.
[0058]
A non-resonant wave also exists as the interfering wave 102 in FIG. 1 described above. No. of FIG. 1 to No. The wave that is first excited with a large amplitude in wave 3 is the 102 non-resonant interfering wave.
[0059]
Thereby, the thick line G in FIG.^~1 (t) wave and thin line G^~If the wave represented by [Equation 3] is created from the wave of 2 (t), the non-resonant interference wave is removed, and if there is a crack 15, only the reflected wave from the crack 15 is obtained.
[0060]
[Equation 3] G^~2 (t) -G^~1 (t)
In FIG. 1 G^~2 (t) -G^~The reflected wave from the crack 15 can be confirmed only by the 1 (t) wave.
[0061]
The G1 (t) and G2 (t) waves (averaged waves) used in the analysis for obtaining FIGS. 11 and 12 are not the optimum waves shown in FIGS. 10A and 10B. The distance l from the crack 15 to the ends of the probes 11 and 12 is simply represented by G^~1 (t) Wave (thick line) 10cm, G^~2 (t) wave (thin line) is 15 cm. As shown in FIGS. 9A and 9B, the positions of the probes 11 and 12 are not determined so that the intensity of the reflected wave from the crack 15 becomes the smallest and the intensity becomes the largest.
[0062]
The above-described method of selecting the optimum probe position (evaluation of the position) will be described below.
[1] G1 (t) wave recording
1). First, as shown in FIG. 1, the probes 11 and 12 are arranged near the ground line 17 in the underground of the utility pole 14, and trial measurement is performed. 1G1 (t) is recorded about 32 times, and a narrowband component wave 1G whose center frequency is around 20 KHz^~1 (t) is created, and 1G is displayed on the measurement screen of the display device 23 of the ultrasonic detection device 20 as shown in FIG.^~Display 1 (t) wave.
[0063]
2). The positions of the probes 11 and 12 are moved downward or upward along the column axis direction at intervals of about Δl = 5 mm or about 10 mm. At the stage where the above movement is completed and the positions of the probes 11 and 12 are fixed, a trial measurement is performed again, and an averaged wave 2G1 (t) of about 32 times is recorded, and a center frequency around 20 KHz is set as described above. Narrowband component wave 2G^~1 (t) is created, and 1G displayed on the measurement screen of the display device 23 of the ultrasonic detection device 20 is displayed.^~1 (t) Above the wave, 2G^~Overlay 1 (t) waves in real time.
[0064]
3). By repeating the above-described test measurement 2), the above-described test measurement wave iG obtained each time is obtained.^~1 (t) is 1G^~When overlaid in real time on 1 (t), if there is a crack 15, 1G^~1 (t) and iG^~The shape of the wave 1 (t) greatly fluctuates as the positions of the probes 11 and 12 fluctuate. (The subscript i is the number of movements).
[0065]
As a result, iG shown by a dotted line in FIG.^~1 (t) wave is obtained. iG^~In the wave of 1 (t), there is a wave having no large amplitude behind the wave. Waves are recorded at the positions of the probes 11 and 12 at this time. Needless to say, the 1G1 (t) wave is an averaging wave in which an appropriate number of averaging times is specified in order to remove disturbance from the measurement environment.
[0066]
4). The above measurement 2) is repeated, and the narrowband component wave iG having a center frequency around 20 KHz of the above-described test measurement wave 1G1 (t) obtained each time is obtained.^~1 (t) is converted to the above 1G^~When drawing over 1 (t), if there is no crack 15, 1G^~1 (t) and iG^~The shape and phase with 1 (t) hardly change. In this case, the positions of the probes 11 and 12 may be determined with an appropriate i, and the averaged wave G1 (t) may be recorded.
[2] G2 (t) wave recording
1). From the averaging wave G1 (t) recorded as described above, a narrow band component wave G having a center frequency of 20 KHz is obtained.^~1 (t) is created, and the above-described G is displayed on the measurement screen of the display device 23 of the ultrasonic detection device 20.^~Display 1 (t) wave. The dotted waveform in FIG.^~It is equivalent to 1 (t).
[0067]
2). The recording position of the above-mentioned G1 (t) wave is determined by the recording of the G1 (t) wave in 3) and 4) of [1]. At the start of G2 (t) wave recording, the probes 11 and 12 are arranged at the above-mentioned determined positions. With this position as the starting point, the probe position is moved downward or upward along the column axis at intervals of about Δl = 5 mm or about 10 mm, and each time, the iG^~Measure 2 (t) waves. iG^~The 2 (t) wave is an averaging wave of about 32 times. The subscript i is the number of times the probes 11 and 12 have moved. If there is a crack 15 at this measurement point, during this trial measurement, iG as shown by the solid line waveform in FIG.^~The display of the 2 (t) wave can be confirmed.
[0068]
Of course, iG^~As described above, the 2 (t) wave is a narrow band component wave extracted from the iG2 (t) wave with the center frequency around 20 KHz. The above-mentioned dotted waveform G^~1 (t) and solid line waveform iG^~2 (t) is displayed in real time on the measurement screen of the display device 34 of the ultrasonic detection device 20 and compared, as shown in FIG.^~As described above, the positions of the probes 11 and 12 where the wave shapes of 1 (t) and iG2 (t) fluctuate greatly are searched, and the G2 (t) waves are recorded at the probe positions. Of course, the G2 (t) wave is an averaging wave specifying an appropriate number of averaging times for removing disturbance from the measurement environment.
[0069]
3). In the recording of the G2 (t) wave shown in the above 2), if the crack 15 does not exist at the measurement point, the above G^~1 (t) wave and 1G^~The shape and phase with the 2 (t) wave hardly change. In this case, the probe position may be determined with an appropriate i, and the averaged wave of G2 (t) may be recorded.
[0070]
As described above, a method of measuring the addition average wave G1 (t) in which the strength of the reflected wave from the crack 15 shown in FIG. 9A is reduced using the component wave of the center frequency around 20 KHz, The method of measuring the averaging wave G2 (t) in which the strength of the reflected wave from the crack 15 shown in FIG. 9B is increased is shown.
[0071]
Note that even if the measurement of G1 (t) is performed in the case of FIG. 9B and the measurement of G2 (t) is performed in the case of FIG.
[0072]
By the way, G^~1 (t), G^~The reason why the center frequency around 20 KHz was adopted in extracting 2 (t) will be described. The thickness d of the telephone pole 14 commonly used in Japan is 40^~It is about 50 mm. From this, the lower limit of the resonance frequency component of the interfering wave shown by 102 in FIG. 1 is calculated based on the aforementioned [Equation 2].
Fd = 4500 m / sec / 2 × 50 mm = 45 KHz in a vertical wave.
0.59fd = almost 24KHz in the horizontal wave.
It is about. Thus, the frequency was set to 20 KHz to avoid the above-mentioned resonance frequency. The reason why the center frequency was not set to a high frequency of 45 KHz or more was to avoid a bad environment due to a resonance phenomenon caused by other interfering waves such as scattered waves.
[0073]
The above [1]. A method of measuring cracks by acquiring waves G1 (t) and G2 (t) according to [2] will be described below as a second embodiment.
[0074]
In the measurement of FIG. 1, the outer diameter of the utility pole 14 is 30 cm, the thickness d is 50 cm, and the distance 1 is 20 cm (the distance from the crack 15 to the end of the bevel jig 13 of the probes 11 and 12 is about 15 cm. )) Is a crack measurement.
[0075]
The distance a between the probes 11 and 12 is 150 mm. G with center frequency around 20KHz^~1 (t) and 1G^~FIG. 15 shows a real-time display example of 2 (t). Fine wire wave is G^~1 (t), and the thick line is iG^~2 (t). The shape of the two waves changes greatly behind the waveform. G2 (t) was recorded at the position of i. Both the G1 (t) and G2 (t) waves are 500 averaged waves.
[0076]
The present embodiment measures G1 (t) along the crack reflection path as shown in FIG. 9A and G2 (t) along the crack reflection path as shown in FIG. The intensity of the reflected wave from the crack 15 included in the G2 (t) wave is large. Thus, it is possible to extract a reflected wave from the crack 15 with a high-frequency component wave even if the frequency is not extremely low as in the first measurement example described above.
[0077]
Naturally, if the reflected wave from the crack 15 can be taken out by the high frequency component, the distance between the crack 15 and the probes 11 and 12 can be measured with higher accuracy. No. shown in FIG. The two waves 1 are component waves in this case. This is a narrow band wave having a center frequency of 91.6 KHz. Thick line is G^~1 (t) Wave, thin line is G^~2 (t) waves. No. The two waves 2 are similar comparison waveforms when there is no crack 15.
[0078]
G^~1 (t) -G^~2 (t)
FIG. 17 shows the result of the above subtraction. No. The occurrence of a wave having an amplitude larger than the cursor position t0 can be confirmed by the subtraction wave of 1. The time at which this wave occurred was 70 μs, and the sound speed cGp of concrete in this example was 4500 m / sec, a = 150 mm, and the probe diameter was 55 mm. When the distance l1 is calculated, l1 = [(70 × 4.5 / 2)²-((150-55) / 2)²]^1/2        = Almost 150mm
It becomes. This value matches the actual value of 150 mm of the distance between the ends of the probes 11 and 12 and the crack 15.
[0079]
On the other hand, FIG. 18 shows G in a frequency band in which an interference wave depending on the pole thickness d of 102 in FIG. 1 causes a resonance phenomenon.^~1 (t) -G^~2 (t). For the above-mentioned reason, the interfering wave remains, and the occurrence of the reflected wave from the crack 15 and its time cannot be confirmed.
[0080]
G mentioned above^~1 (t), G^~At 2 (t), the first large amplitude wave that occurred was the jammer 102 in FIG.
[0081]
A narrow-band component wave G having a frequency lower than the frequency f0 shown in the above [Equation 1] and having a center frequency other than the frequency band shown in [Equation 2].^~1 (t) and G^~In 2 (t), in most cases, the shape and intensity of the wave are almost the same, and the phase shift is very small. The above-described first and second embodiments are measurement examples in such a case, and the reflected wave from the crack 15 is obtained by using [Equation 3].
G^~1 (t) -G^~2 (t)
Was what I wanted.
[0082]
By the way, as shown in FIG. 19, the main reinforcement 19a is arranged in the concrete of the electric pole 14 in the column axis direction, and the spiral hoop reinforcement 19b is arranged in the circumferential direction thereof.
[0083]
On the other hand, in the recording of the aforementioned G1 (t) and G2 (t) waves, the moving directions of the probes 11, 12 were in the column axis direction. Thus, depending on the position of the probes 11 and 12, the reflected wave from the spiral hoop muscle 19b may be received or not.
[0084]
This wave is generated by being superimposed on the 102 interfering wave. Also, as shown in FIG. 20, when there is a vertical fair crack 501 or the like near the arrangement of the probes 11 and 12, as shown, depending on the positions of the probes 11 and 12, 102 interfering waves are generated. It may be interrupted by the fair crack 501.
[0085]
In such a case, the aforementioned G^~1 (t), G^~The superimposed wave of the large amplitude wave 102 generated at the beginning of the 2 (t) wave and the reflected wave from the spiral hoop muscle 19b and the like have different shapes and intensities, and also have a phase shift.
[0086]
To address this issue,
1). G mentioned above^~1 (t), G^~At 2 (t),
G occurring after the first occurrence time t0 = 2d / cVp of the 102 detection disturbance wave represented by the thickness d of the telephone pole 14 and the concrete sound velocity cVp^~1 (t), G^~At time tw of any of the first, second, third, and fourth wave peaks and valleys of 2 (t), G^~1 (t), G^~2 (t) is matched by shifting one of the waves back and forth by time Δt.^~1 (t), G^~Instead of 2 (t), the correction waves H1 (t) and H2 (t) whose time axes have moved each other by the time Δt are obtained, and the wave shown in [Equation 4] is created.
[0087]
[Formula 4] H1 (t) -H2 (t) or H2 (t) -H1 (t)
2). G mentioned above^~1 (t), G^~At 2 (t),
G occurring after the first occurrence time t0 = 2d / cVp of the above-mentioned detection interference wave.^~1 (t), G^~At time tw of any of the first, second, third, and fourth wave peaks and valleys of 2 (t), G^~1 (t), G^~2 (t) is matched by shifting one of the waves back and forth by time Δt.^~1 (t), G^~Instead of 2 (t), the correction waves H1 (t) and H2 (t), whose time axes have moved each other by the time Δt, are obtained,
G at time tw^~1 (t), G^~The absolute value of the amplitude value of 2 (t) is defined as W1 and W2, respectively, and a wave shown in [Equation 5] is created.
[0088]
[Formula 5] W2 / W1 H1 (t) -H2 (t)
Or W1 / W2 H2 (t) -H1 (t)
Note that W2 / W1H1 (t) and W1 / W2H2 (t) can be referred to as corrected correction waves.
[0089]
By using the waves created by the above-described [Equation 4] and [Equation 5], the case where the reflected wave from the spiral hoop muscle 19b and the like are included in the G1 (t) and G2 (t) waves. Even if there is, the generation of the reflected wave from the crack 15 can be specified even when there is a fair crack 501 or the like near the arrangement of the probes 11 and 12.
[0090]
As the third embodiment, the outer diameter of the utility pole shown in the second embodiment is 30 cm, the wall thickness d = 50 mm, the distance from the crack 15 to the end of the angled jig 13 is 15 cm, and the distance a between the transmitting and receiving probes 11 and 12 is a. The above [Equation 4] and [Equation 5] are applied to the crack measurement when is set to 150 mm.
[0091]
FIG. 16 shows G which is a narrow band component wave having a center frequency of 91.6 KHz.^~1 (t) and G^~2 (t) is indicated by a thick line and a thin line, respectively. No. At the measurement point of No. 1, a crack 15 was found 15 cm below the ends of the probes 11 and 12. The measurement at point 2 was a measurement without cracks. FIG. 21 shows the result of applying [Equation 4] at the illustrated cursor position tw = 41.9 μsec, and FIG. 22 shows the result of applying [Equation 5]. The results of both sides to which [Equation 4] and [Equation 5] are applied, The reflected wave from the crack 15 at the measurement point 1 is clearly extracted.
[0092]
Each of the waves shown in the first, second, and third embodiments is f (t) when the actual wave is expressed as f (t) except for FIGS. 4, 7, 10, 11, 13, 14, 15, and 16.²(t) or f³Indicated by (t), the peak is intensified.
[0093]
The present invention not only detects cracks in the underground portion of the telephone pole, the wall of the wall, and the paper band preventing band, but also detects the depth of the pole 13 of the telephone pole 13 as shown in FIG. And can be applied as it is. This is because the reflection from the lower end of the utility pole is technically exactly the same as the reflection from the crack.
[0094]
In the above, one embodiment of the present invention has been described. However, the present invention is not limited to the configuration of the above-described embodiment, but includes many embodiments.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a longitudinal section and a transverse section of ultrasonic detection.
FIG. 2 is a configuration block diagram of an ultrasonic detection device.
FIG. 3 is an explanatory view of arrangement of probes.
FIG. 4 is a waveform diagram of a detection wave.
FIG. 5 is an explanatory view of a cross section showing an arrangement of probes at the time of detection.
FIG. 6 is a waveform diagram of a broadband ultrasonic wave.
FIG. 7 is a waveform diagram of a time-series wave.
FIG. 8 is a waveform chart showing a spectrum shape of a narrowband component wave.
FIG. 9 is a schematic diagram showing a state of a reflected wave in a vertical section.
FIG. 10 is a waveform diagram schematically showing extraction of a component wave.
FIG. 11 is a waveform diagram of a low-frequency narrow-band component wave extracted from the averaging wave.
FIG. 12 is a waveform diagram of a detection wave created by Expression 3.
FIG. 13 Wave 1G^~1 (t) is a waveform diagram.
FIG. 14 Wave 1G^~1 (t) and test measurement wave iG^~Waveform diagram with 1 (t) superimposed.
FIG. 15: Wave G^~1 (t) and 1G^~2 (t) is a waveform diagram superimposed.
FIG. 16 is a waveform diagram of a high-frequency component.
FIG. 17 is a waveform chart after a subtraction process is performed.
FIG. 18 is a waveform chart in which a subtraction process is performed in a frequency band in which an interference wave causes a resonance phenomenon.
FIG. 19 is a longitudinal sectional view of a utility pole provided with a reinforcing bar.
FIG. 20 is a cross-sectional view of a utility pole having a fair crack.
FIG. 21 is a waveform diagram of a detection wave created by Expression 4.
FIG. 22 is a waveform diagram of a detection wave created by Expression 5.
FIG. 23 is a longitudinal sectional view of a utility pole of another example.
[Explanation of symbols]
11… Transmitting probe
12 ... Reception probe
13 ... bevel jig
14 ... telephone pole
15 ... crack
20 Ultrasonic detector
21 ... Pulse generator
22 ... Analyzer
22f ... Hard disk
23 Display device
25 ... CD

Claims (15)

An ultrasonic detection method for receiving a reflected wave of an ultrasonic wave transmitted in an oblique direction from the surface of the detected object to the detection direction side, and detecting a state inside the detected object,
A first detection position for receiving and detecting the transmitted reflected wave of the ultrasonic wave with respect to the detection target object, and moving the first detection position from the first detection position to the far side in the detection direction by a predetermined amount to perform a first detection; The averaged waves G1 (t) and G2 (t), which evaluate the second detection position to be detected in the same manner as the detection position and add the received waves obtained for each ultrasonic output at each position to obtain an average value ) is calculated, and these averaged wave G1 (t), G2 (t ) narrowband component wave G ^{~ 1} (t) around a predetermined frequency from each to create a G ~ ^{2 (t),} these narrow An ultrasonic detection method for detecting a form inside a detection target object by comparing waveform shapes of band component waves G ^- 1 (t) and G ^- 2 (t). 2. The method according ^{to claim} 1, wherein a detection wave is calculated by subtracting the narrow-band component waves G 1 ^to 1 (t) and G 2 ^to 2 (t), and a shape inside the detection target object is detected by a waveform shape of the detection wave. Ultrasonic detection method. When a waveform having a large amplitude is generated in the detection wave, the generation time tl of the waveform is calculated, and the position of the morphological change is determined based on the generation time tl and the ultrasonic propagation speed cVp of the detected object. The ultrasonic detection method according to claim 2, wherein the calculation is performed. The narrowband component wave G ^{~ 1} (t), first with calculating a Okoshisei time t0 large amplitude wave Okoshisei, the narrow band Okoshisei this Okoshisei after time t0 of G ~ ^{2 (t)} component wave G ^{~ 1} (t), in the first or a plurality th either wave crests or wave trough of time tw in the G ~ ^{2 (t),} the two narrowband component wave ^{G ~ 1 (t), G} ~ The correction waves H1 (t) and H2 (t) are generated when one of the waves 2 (t) is shifted back and forth on the time axis to match the waveforms, and these correction waves H1 (t) and H2 (t) are generated. The ultrasonic detection method according to claim 1, wherein a shape inside the detected object is detected by comparing the waveform shapes of the ultrasonic waves. 5. The ultrasonic detection method according to claim 4, wherein a detection wave is calculated by subtracting the correction waves H1 (t) and H2 (t), and a shape inside the detection target object is detected by a waveform shape of the detection wave. The wave crests or ^~ narrowband component wave G at time tw of wave trough ¹ (t), absolute value W1, W2 and calculates respective ^{G-2 (t),} the correction wave quotient of these absolute values W1, W2 H1 ( t) and H2 (t) are corrected so that both waves correspond to the other, and one corrected correction wave W2 / W1 · H1 (t) and the other correction wave H2 (t) or 5. The ultrasonic detection method according to claim 4, wherein a detection wave is calculated by subtracting W1 / W2 · H2 (t) and H1 (t), and a form inside the detected object is detected by a waveform shape of the detection wave. . When the thickness of the object to be detected d, said object of the ultrasonic propagation velocity CVP, the diameter of the probe, based on the engagement number, the intensity of the fault wave propagating in a direction transverse to detect the direction from the probe is reduced the first frequency f0, calculates the resonant fault frequency fd, the narrow-band component wave G ^{~ 1} (t), lower than G ~ ^{2 (t)} said first frequency f 0 of a predetermined frequency to create a 7. The method according to claim 1, wherein the frequency is selected, and the resonance frequency fd is removed to create narrowband component waves G ^- 1 (t) and G ^- 2 (t). Ultrasonic detection method. Ultrasonic wave generating means having a probe that transmits ultrasonic waves and receives the reflected waves,
The probe of the ultrasonic wave generating means such that the direction of the probe of the ultrasonic wave generating means is directed obliquely from the surface of the detected object with respect to the detected object, and the direction side is set to the detection direction side. Angle holding means for holding
A first detection position for receiving and detecting the reflected wave of the ultrasonic wave transmitted from the probe with respect to the detection target object, and moving from the first detection position by a predetermined amount to the far side and the near side in the detection direction. Averaged wave G1 (t) that evaluates the second detected position to be detected in the same manner as the first detected position and adds the received waves obtained for each ultrasonic output at each position to obtain an average value calculates the G2 (t), these averaged wave G1 (t), G2 (t ) narrowband component wave G ^{~ 1} (t) around a predetermined frequency from each, create a G ~ ^{2 (t)} An ultrasonic detection apparatus comprising: an arithmetic means for detecting the internal shape of the detection target object by comparing the waveform shapes of the narrow-band component waves G ^- 1 (t) and G ^- 2 (t). It said calculating means narrowband component wave G ^{~ 1} calculated in (t), G ~ ^{2 (t),} calculates the detection wave and subtraction processing, detect object to be detected inside the form at the waveform of該探knowledge wave The ultrasonic detection device according to claim 8, further comprising a calculation unit that performs the calculation. When a waveform having a large amplitude is generated in the detection wave calculated by the calculation means, an occurrence time tl of the waveform is calculated, and based on the occurrence time tl and the ultrasonic wave propagation velocity cVp of the detected object. The ultrasonic detection device according to claim 9, further comprising a calculation unit configured to calculate the position of the morphological change. Said calculating means narrowband component wave G ^{~ 1} calculated in (t), as well as calculating the beginning of the large amplitude waves Okoshisei Okoshisei time t0 in G ~ ^{2 (t),} this Okoshisei after time t0 At the time tw of any of the first to plural wave peaks or troughs on the narrow band component waves G ^to 1 (t) and G ^to 2 (t) occurring, the two narrow band component waves G ^to 1 (t), one of the waves G ^to 2 (t) is shifted back and forth on the time axis to create correction waves H1 (t) and H2 (t) when the waveforms are matched, and these correction waves H1 (t) 9. The ultrasonic detecting apparatus according to claim 8, further comprising a calculating means for detecting a form inside the detected object by comparing the waveform shapes of H2 (t) and H2 (t). A calculating means for calculating a detection wave by subtracting the correction waves H1 (t) and H2 (t) calculated by the calculation means, and detecting a form inside the detection target object by a waveform shape of the detection wave; The ultrasonic detection device according to claim 11. The absolute values W1 and W2 of the narrow band component waves G ^- 1 (t) and G ^- 2 (t) at the time tw of the wave crest or wave trough calculated by the calculating means are calculated, respectively, and the quotient of these absolute values W1 and W2 is calculated. To correct one of the correction waves H1 (t) and H2 (t) so as to be equal to the other, and to correct one of the correction waves W2 / W1 · H1 (t) and the other correction wave H2 ( t) or W1 / W2 · H2 (t) and H1 (t) are subtracted to calculate a detection wave, and a calculation means is provided for detecting the internal shape of the detected object by the waveform shape of the detection wave. 12. The ultrasonic detection device according to item 11. When the thickness of the object to be detected d, said object of the ultrasonic propagation velocity CVP, the diameter of the probe, based on the engagement number, the intensity of the fault wave propagating in a direction transverse to detect the direction from the probe is reduced the first frequency f0, calculates the resonant fault frequency fd, the narrow-band component wave G ^{~ 1} (t), lower than G ~ ^{2 (t)} said first frequency f 0 of a predetermined frequency to create a 14. A method according to claim 8, further comprising calculating means for selecting a frequency and removing the resonance frequency fd to create narrowband component waves G ^- 1 (t) and G ^- 2 (t). The ultrasonic detection device according to claim. g. Ultrasonic detection that transmits an ultrasonic wave and is read by a computer having an ultrasonic wave generating unit that receives the reflected wave, thereby controlling the arithmetic unit of the computer and causing the computer to detect a form inside the object to be detected. A signal processing recording medium recording a computer program to function as an apparatus,
h. The arithmetic means receives the reflected wave of the ultrasonic wave transmitted obliquely from the surface of the detected object to the detection direction side by the ultrasonic wave generating means with respect to the detected object, and changes the state inside the detected object. An evaluation process of evaluating a first detection position to be detected, and a second detection position to be moved by a predetermined amount from the first detection position to the far side in the detection direction and to detect the same as the first detection position;
i. An arithmetic processing for calculating the averaged waves G 1 (t) and G 2 (t) for adding the received waves obtained for each ultrasonic output at each position to obtain an average value ;
j. These averaging wave G 1 (t), G 2 (t) of the narrow-band component wave G ^~ about a predetermined frequency from each ¹ (t), and creation processing for creating a G ~ ^{2 (t),}
k. By comparing the waveform shapes of these narrow-band component waves G ^- 1 (t) and G ^- 2 (t) , an analysis process for detecting the internal shape of the detected object is performed.
Recorded computer program to be executed l. Signal processing recording medium.

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