JP4631055B2 - Stress evaluation method and apparatus using surface acoustic waves - Google Patents
Stress evaluation method and apparatus using surface acoustic waves Download PDFInfo
- Publication number
- JP4631055B2 JP4631055B2 JP2005243512A JP2005243512A JP4631055B2 JP 4631055 B2 JP4631055 B2 JP 4631055B2 JP 2005243512 A JP2005243512 A JP 2005243512A JP 2005243512 A JP2005243512 A JP 2005243512A JP 4631055 B2 JP4631055 B2 JP 4631055B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- surface acoustic
- acoustic wave
- stress
- measured
- 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.)
- Active
Links
Landscapes
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Description
本発明は、弾性表面波の伝播により逆磁歪効果で生じた振動磁界とバイアス磁界とにより磁性体表面から漏洩する磁界を検知することにより、磁性体に生じている応力を評価する、表面弾性波による応力評価方法および装置に関する。 The present invention evaluates the stress generated in a magnetic material by detecting a magnetic field leaking from the surface of the magnetic material by an oscillating magnetic field and a bias magnetic field generated by the inverse magnetostriction effect due to propagation of the surface acoustic wave. The present invention relates to a stress evaluation method and apparatus.
非破壊検査の代表的な方法として、超音波探傷法がある。この方法は材料表面や内部の傷を発見するには有効な手段ではあるものの、傷の発生原因となる残留応力の存在を推定することはできないことから非破壊検査において残留応力の存在も測定できることが望まれている。その中で、Ｘ線による方法やバルクハウゼン雑音を観察する方法もあるが使用上の難点がある。 As a typical method of nondestructive inspection, there is an ultrasonic flaw detection method. Although this method is an effective means to detect scratches on the material surface and inside, it is impossible to estimate the presence of residual stress that causes scratches, so it can also measure the presence of residual stress in nondestructive inspection. Is desired. Among them, there are a method using X-rays and a method for observing Barkhausen noise, but there are difficulties in use.
特許文献１には、寿命応力診断部位の残留応力を、Ｘ線法、磁歪法、超音波法、コアドリル法、センタードリル法の何れかの方法で定期的に測定し、寿命診断部位の温度や圧力や遠心力等により計算される応力値に残留応力分を補正することで、精度の高い寿命診断を行う方法が開示されている。
特許文献２には、鋼板の表面にバイアス磁界を印加すると共にこのバイアス磁界と同一平面内で直交し互いに逆行するように誘導磁界を印加させることで磁歪を生じさせ、この磁歪により生じる表面波の二方向への伝播速度の違いから、内部応力を評価することが開示されている。
特許文献３および非特許文献１には、磁性体一端の弾性波発生器からの入射弾性波と磁性体の他端からの反射弾性波とで定在波を形成し、この定在波の節に応力が生じることを利用して、該応力の逆磁歪効果で生じる異方性磁界の振動磁界から磁性体の残留歪みを測定することが開示されている。
In Patent Document 1, the residual stress at the life stress diagnosis site is periodically measured by any of the X-ray method, magnetostriction method, ultrasonic method, core drill method, center drill method, There is disclosed a method for performing a life diagnosis with high accuracy by correcting a residual stress component to a stress value calculated by pressure, centrifugal force, or the like.
In Patent Document 2, a bias magnetic field is applied to the surface of the steel sheet, and an induced magnetic field is applied so as to be orthogonal to and opposite to each other in the same plane as the bias magnetic field, thereby generating magnetostriction. It is disclosed that the internal stress is evaluated from the difference in propagation speed in two directions.
In Patent Document 3 and Non-Patent Document 1, a standing wave is formed by an incident elastic wave from an elastic wave generator at one end of a magnetic body and a reflected elastic wave from the other end of the magnetic body. It is disclosed that the residual strain of a magnetic material is measured from an oscillating magnetic field of an anisotropic magnetic field generated by the inverse magnetostriction effect of the stress using the fact that stress is generated in the magnetic field.
しかしながら、特許文献２に開示された方法は、鋼板等の生産現場では有用であるが、疲労した被測定物の残留応力を測定する場合には、疲労によって被測定物の硬度が高くなり、硬度が高くなると一般に弾性率が大きくなるために表面波の伝搬速度が大きくなる。また、疲労個所は表面全体に亘って一様ではないので、残留応力のみに基づく表面波の二方向への伝播速度の違いを正確に測定することは困難である。従ってこの様な場合には、この測定方法では正確に測定することが困難であるという課題がある。また、誘導磁界により表面波を発生させるため、その発生効率が良くない。また、特許文献３の方法は、超音波を印加するために被測定物の断面を必要とし、測定が簡便に行えないという課題がある。
このように、従来は、疲労等の被測定物の状態によらず、また、簡便に、残留応力を測定できる方法及び装置が知られていなかった。
However, the method disclosed in Patent Document 2 is useful in production sites such as steel sheets, but when measuring the residual stress of a measured object that has been fatigued, the hardness of the measured object increases due to fatigue. Generally, the elastic modulus increases as the value increases, so that the propagation speed of the surface wave increases. In addition, since the fatigue location is not uniform over the entire surface, it is difficult to accurately measure the difference in the propagation speed of the surface wave in two directions based only on the residual stress. Therefore, in such a case, there is a problem that it is difficult to measure accurately with this measurement method. Moreover, since the surface wave is generated by the induced magnetic field, the generation efficiency is not good. Moreover, the method of patent document 3 requires the cross section of a to-be-measured object in order to apply an ultrasonic wave, and there exists a subject that a measurement cannot be performed simply.
Thus, conventionally, there has been no known method and apparatus that can easily measure the residual stress regardless of the state of the measured object such as fatigue.
そこで、本発明は、上記課題に鑑み、磁性体表面に弾性表面波を伝播させることで生じる振動磁界を利用して、磁性体内部に生じている応力を、正確、且つ、簡便に評価することができる、弾性表面波による応力評価方法および装置を提供することを目的とする。 Therefore, in view of the above problems, the present invention makes it possible to accurately and easily evaluate the stress generated in the magnetic body by using the oscillating magnetic field generated by propagating the surface acoustic wave to the surface of the magnetic body. An object of the present invention is to provide a stress evaluation method and apparatus using surface acoustic waves.
上記課題を解決するために、本発明の弾性表面波による応力評価方法は、磁性体に弾性表面波を伝播させると共にこの弾性表面波の伝播方向に平行にバイアス磁界を印加し、この弾性表面波による逆磁歪効果で振動磁界を生じさせると共に磁性体表面から磁界を漏洩させ、この漏洩した磁界を測定することにより、磁性体内部に存在する応力を評価することを特徴とする。
特に、弾性表面波の伝播方向を前記バイアス磁界の方向と同一方向および逆方向にした各漏洩磁界を比較することにより、磁性体内部に存在する応力を評価する。
または、弾性表面波の伝播方向を一定とし、バイアス磁界の方向を弾性表面波の伝播方向と同一方向および逆方向にした各漏洩磁界を比較することにより、磁性体内部に存在する応力を評価しても良い。
好ましくは、磁性体表面に対して所定の入射角度で超音波を入射させることにより、磁性体に弾性表面波を生じさせる。
In order to solve the above problems, the stress evaluation method using surface acoustic waves according to the present invention propagates a surface acoustic wave to a magnetic material and applies a bias magnetic field parallel to the propagation direction of the surface acoustic wave. An oscillating magnetic field is generated due to the inverse magnetostrictive effect of, and a magnetic field is leaked from the surface of the magnetic material. By measuring the leaked magnetic field, the stress existing in the magnetic material is evaluated.
In particular, the stress existing in the magnetic material is evaluated by comparing each leakage magnetic field in which the propagation direction of the surface acoustic wave is the same direction as that of the bias magnetic field and in the opposite direction.
Alternatively, the stress existing in the magnetic material can be evaluated by comparing each leakage magnetic field with the propagation direction of the surface acoustic wave constant and with the bias magnetic field direction the same and opposite to the propagation direction of the surface acoustic wave. May be.
Preferably, an ultrasonic wave is incident on the magnetic material surface at a predetermined incident angle to generate a surface acoustic wave in the magnetic material.
上記構成により、磁性体に伝播させた弾性表面波による磁性体各部の圧縮および伸長による逆磁歪効果で生じる振動漏洩磁界に基づいて磁性体に存在する応力を評価するので、被測定物の表面状態によらずに、例えば、被測定物の表面が不均一に硬化していても、残留応力を測定できる。特に、弾性表面波の伝播方向をバイアス磁界の方向と同一にした場合と逆向きにした場合で各漏洩磁界を測定し、測定データを比較することで、容易に磁性体に生じている応力の有無を判別することができる。また、弾性表面波の伝播方向を一定とし、バイアス磁界の方向を弾性表面波の伝播方向と同一方向および逆方向にした各漏洩磁界を比較することによっても、磁性体内部に存在する応力を評価することができる。 With the above configuration, the stress present in the magnetic body is evaluated based on the vibration leakage magnetic field generated by the inverse magnetostriction effect caused by the compression and expansion of each part of the magnetic body by the surface acoustic wave propagated to the magnetic body. Regardless of this, for example, even if the surface of the object to be measured is hardened unevenly, the residual stress can be measured. In particular, by measuring each leakage magnetic field when the propagation direction of the surface acoustic wave is the same as the direction of the bias magnetic field, and by comparing the measured data, the stress generated in the magnetic material can be easily compared. The presence or absence can be determined. Also, the stress existing in the magnetic material can be evaluated by comparing each leakage magnetic field with the propagation direction of the surface acoustic wave constant and with the bias magnetic field in the same direction as the propagation direction of the surface acoustic wave. can do.
本発明の弾性表面波による応力評価装置は、被測定物上に配置される弾性表面波発生器と、弾性表面波発生器により被測定物表面に励起され、被測定物表面を伝播する弾性表面波の伝播方向に平行なバイアス磁界を印加する磁界印加コイルと、磁界印加コイルによるバイアス磁界と上記弾性表面波により被測定物に生じる振動磁界とにより被測定物表面から漏洩する磁界を検知するセンサーと、を備えたことを特徴とする。
好ましくは、弾性表面波発生器が、超音波振動子と、超音波振動子からの超音波を被測定物表面に斜め上方より照射するように、超音波振動子を斜めに保持する保持台と、を含む。
A surface acoustic wave generator according to the present invention includes a surface acoustic wave generator disposed on a measurement object, and an elastic surface that is excited by the surface acoustic wave generator and propagates through the measurement object surface. A magnetic field application coil that applies a bias magnetic field parallel to the wave propagation direction, and a sensor that detects a magnetic field leaking from the surface of the object to be measured by the bias magnetic field generated by the magnetic field application coil and the oscillating magnetic field generated in the object by the surface acoustic wave. And.
Preferably, the surface acoustic wave generator includes an ultrasonic vibrator, and a holding table that holds the ultrasonic vibrator diagonally so that the ultrasonic wave from the ultrasonic vibrator is irradiated to the surface of the measurement object obliquely from above. ,including.
上記構成により、被測定物に弾性表面波発生器を載置し、弾性表面波発生器により被測定物表面に弾性表面波を励起すると共に磁界印加コイルにより弾性表面波の伝播方向に平行なバイアス磁界を印加し、弾性表面波の伝搬によって生じる振動漏洩磁界を磁界をセンサーにより測定することで、応力を評価することができる。 With the above configuration, a surface acoustic wave generator is mounted on the object to be measured, and the surface acoustic wave is excited on the surface of the object to be measured by the surface acoustic wave generator, and a bias parallel to the propagation direction of the surface acoustic wave is applied by the magnetic field application coil. Stress can be evaluated by applying a magnetic field and measuring the vibration leakage magnetic field generated by the propagation of the surface acoustic wave with a sensor.
本発明は、弾性表面波が磁性体を伝播することにより生ずる磁性体表面の振動漏洩磁界を、弾性表面波の伝播方向、または、バイアス磁場の方向を変えて比較することにより、磁性体内部に存在する応力を評価することができるので、磁性体からなる各種構造物の応力を正確に、しかも簡便に測定することができる。 In the present invention, the vibration leakage magnetic field on the surface of the magnetic material generated by the surface acoustic wave propagating through the magnetic material is compared by changing the propagation direction of the surface acoustic wave or the direction of the bias magnetic field. Since the existing stress can be evaluated, the stress of various structures made of a magnetic material can be accurately and easily measured.
以下、図面を参照して本発明を実施するための最良の形態を説明する。
先ず、本発明の原理を説明する前提として、逆磁歪効果について説明する。
図１は、磁性体の磁気歪み特性曲線である。図において横軸は磁性体に印加する磁界を示し、縦軸は磁気歪みλを表している。図に示すように、バイアス磁界ＨDCを動作点として、周波数ωの応力σ（ω）を磁性体に加え、磁性体に機械的歪みε（ω）を加えると、ε（ω）は磁気歪みλ（ω）に等価な歪みを伴い、その結果、異方性磁界Ｈe （ω）が生じる。この効果は、磁界を印加して磁性体を機械的に歪ませることの逆であるので、逆磁歪効果という。
次に異方性磁界Ｈe の大きさと方向を説明する。応力σの印加により、磁性体の応力場には、磁気弾性エネルギーＫe が発生する。この効果は、逆磁歪効果と呼ばれ、等方性磁性体の場合には、（１）式で表される。
Ｋe ＝−（３／２）λσｃｏｓ2 θ （１）
ここで、λは磁気歪み量、θは応力σと磁化Ｉとのなす角である。異方性磁界Ｈe の大きさは次式（２）によって表される。
Ｈe ＝２Ｋe ／Ｉ （２）
異方性磁界Ｈe の方向は、（１）式の磁気弾性エネルギーＫe が最小となる方向であり、単位体積当たりの磁気モーメント、すなわち磁化Ｉが、Ｋe が最小となる方向に回転し、回転した磁化Ｉの方向が異方性磁界Ｈe の方向となる。
The best mode for carrying out the present invention will be described below with reference to the drawings.
First, the inverse magnetostriction effect will be described as a premise for explaining the principle of the present invention.
FIG. 1 is a magnetostriction characteristic curve of a magnetic material. In the figure, the horizontal axis represents the magnetic field applied to the magnetic material, and the vertical axis represents the magnetostriction λ. As shown in the figure, when a stress σ (ω) at a frequency ω is applied to a magnetic material with a bias magnetic field HDC as an operating point, and mechanical strain ε (ω) is applied to the magnetic material, ε (ω) with an equivalent strain in λ (ω), as a result, the anisotropic magnetic field H e (ω) occurs. Since this effect is the opposite of mechanically distorting a magnetic material by applying a magnetic field, it is called an inverse magnetostriction effect.
Next will be described the magnitude and direction of the anisotropic magnetic field H e. By applying the stress σ, magnetoelastic energy Ke is generated in the stress field of the magnetic material. This effect is called an inverse magnetostriction effect, and is expressed by equation (1) in the case of an isotropic magnetic material.
K e = − (3/2) λσcos 2 θ (1)
Here, λ is the amount of magnetostriction, and θ is the angle between the stress σ and the magnetization I. The magnitude of the anisotropy field H e is expressed by the following equation (2).
H e = 2K e / I (2)
Direction of the anisotropic magnetic field H e is (1) a direction magnetoelastic energy K e is the smallest, magnetic moment per unit volume, i.e. the magnetization I is rotated in the direction of K e is minimized , the direction of the rotated magnetization I becomes the direction of the anisotropic magnetic field H e.
次に、これを前提に弾性表面波による漏洩磁界の発生原理について説明する。
一般に弾性体表面付近にエネルギーを集中して伝播する音波を称して、弾性表面波（Surface Acoustic Wav:SAW）と呼んでいる。
図２は、弾性表面波による漏洩磁界の発生原理を模式的に示した図で、（ａ）は、被測定物体の弾性表面波伝播による応力分布を、（ｂ）は被測定物体の逆磁歪効果による磁気モーメントの変化を、（ｃ）はさらにバイアス磁界を印加した時の被測定物体の内部磁界の状態を示している。なお、（ａ）に於ける矢印は応力σの大きさと方向を表し、（ｂ）及び（ｃ）に於ける矢印は磁気モーメント（磁化）の大きさと方向を表す。
図２（ａ）に示すように、磁性体に弾性表面波が図の矢印Ａの方向に伝播しているときには、波の山や谷の部分には応力１が加わっている。すなわち、波の山に当たる部分（図のＢの部分）には張力が働いて伸びており、正の応力が働いている。逆に波の谷に当たる部分（図のＣの部分）には圧力が加わって縮んでおり、負の応力が働いている。すると、前述のように、圧力や張力が加わっている部分には、逆磁歪効果で、弾性エネルギーＫe が発生する。
Next, the generation principle of the leakage magnetic field due to the surface acoustic wave will be described on the premise of this.
Generally speaking, sound waves that propagate energy concentrated near the surface of an elastic body are called surface acoustic waves (SAW).
2A and 2B are diagrams schematically showing the principle of generation of a leakage magnetic field caused by surface acoustic waves. FIG. 2A shows the stress distribution due to surface acoustic wave propagation of the object to be measured, and FIG. 2B shows the inverse magnetostriction of the object to be measured. (C) shows the state of the internal magnetic field of the object to be measured when a bias magnetic field is further applied. The arrows in (a) represent the magnitude and direction of the stress σ, and the arrows in (b) and (c) represent the magnitude and direction of the magnetic moment (magnetization).
As shown in FIG. 2A, when a surface acoustic wave propagates through the magnetic material in the direction of arrow A in the figure, stress 1 is applied to the peak and valley portions of the wave. That is, tension is applied to the portion corresponding to the peak of the wave (portion B in the figure), and positive stress is applied. On the contrary, the portion that corresponds to the valley of the wave (the portion C in the figure) is contracted by pressure, and negative stress is acting. Then, as described above, elastic energy Ke is generated in the portion where pressure or tension is applied due to the inverse magnetostriction effect.
磁気歪み量λが負である磁性体、すなわち、逆磁歪効果によって磁界が増加する磁性体の場合には、図２（ｂ）に示すように、応力σが正の部位、即ち、張力が働いて伸びている部位（波の山の部位、例えばＢ）では、（１）式より、磁気弾性エネルギーＫe が最小となる応力σと磁気モーメント２とのなす角θは、π／２または３π／２であるから、図のように、磁気モーメント２は波の伝播方向に垂直になる。一方、応力σが負の部位、即ち、圧力が働いて縮んでいる部位（波の谷の部位、例えばＣ）では、（１）式より、磁気弾性エネルギーＫe が最小となる応力σと磁気モーメント２とのなす角θは、０又は２πであるから、図のように、磁気モーメント２は波の伝播方向に平行になる。
上記とは逆に、磁気歪み量λが正の磁性体、すなわち、逆磁歪効果によって磁界が増加する磁性体の場合には、（１）式から同様に、応力σが負の部位、即ち谷の部位の磁気モーメント２が弾性表面波の進行方向に対して垂直になり、応力σが正の部位、即ち山の部位の磁気モーメントは弾性表面波の進行方向に対して水平になる。
In the case of a magnetic body having a negative magnetostriction amount λ, that is, a magnetic body in which the magnetic field increases due to the inverse magnetostriction effect, as shown in FIG. From the equation (1), the angle θ between the stress σ at which the magnetoelastic energy K e is minimum and the magnetic moment 2 is π / 2 or 3π. Therefore, as shown in the figure, the magnetic moment 2 is perpendicular to the wave propagation direction. On the other hand, in a portion where the stress σ is negative, that is, a portion where the pressure is applied and the portion is contracted (portion of the wave valley, for example, C), the stress σ and the magnetism at which the magnetoelastic energy Ke is minimum are obtained from the equation (1). Since the angle θ formed with the moment 2 is 0 or 2π, the magnetic moment 2 is parallel to the wave propagation direction as shown in the figure.
Contrary to the above, in the case of a magnetic material having a positive magnetostriction amount λ, that is, a magnetic material in which the magnetic field increases due to the inverse magnetostriction effect, similarly to the equation (1), the portion where the stress σ is negative, that is, the valley The magnetic moment 2 of the part is perpendicular to the traveling direction of the surface acoustic wave, and the magnetic moment of the part where the stress σ is positive, that is, the mountain part is horizontal to the traveling direction of the surface acoustic wave.
さらに、隣り合う山と山、或いは谷と谷の磁気モーメントは、これらの磁気モーメントが形成する磁気エネルギーが最小になるように互いに反対方向を向くようになる。従って、例えば、図２（ｂ）に示すように、磁気モーメント３が、θ＝π／２、で上向きであるとすれば、隣り合う山の磁気モーメント３’は、θ＝３π／２、となって下向きとなる。このため、被測定物体の表面近傍に、被測定物体内部から漏れだした磁界、すなわち、揺曳磁界Φが発生する。
ところで、逆磁歪効果により発生する磁界の大きさは、磁気歪み曲線の傾斜に依存するため、より大きな磁界を発生させるためには、外部からバイアス磁界を印加することが有効である。
図２（ｃ）に示すように、弾性表面波の伝播方向に平行にバイアス磁界ＨDEを印加すると、磁性体内部では、磁気モーメント２は、印加したバイアス磁界ＨDEの方向に揃う。一方、磁性体表面では、バイアス磁界ＨDEは逆磁歪効果で発生する磁界と合成され、例えば、上向き磁気モーメント３はバイアス磁界ＨDEと合成されて角度Ｈ+ のやや上向き方向の磁気モーメント４となり、隣り合う山の下向き磁気モーメント３’はバイアス磁界ＨDEと合成されて角度Ｈ- のやや下向き方向の磁気モーメント４’となる。上記と同様に、磁気モーメント４と４’の被測定物体の表面に垂直な成分の符号が反対であることから、漏洩磁界Φが発生する。
Furthermore, the magnetic moments of adjacent peaks and peaks or valleys and valleys are directed in opposite directions so that the magnetic energy formed by these magnetic moments is minimized. Therefore, for example, as shown in FIG. 2B, if the magnetic moment 3 is upward at θ = π / 2, the magnetic moment 3 ′ of the adjacent mountain is θ = 3π / 2. Become downward. For this reason, a magnetic field leaking from the inside of the measured object, that is, a fluctuation magnetic field Φ is generated near the surface of the measured object.
By the way, since the magnitude of the magnetic field generated by the inverse magnetostriction effect depends on the gradient of the magnetostriction curve, it is effective to apply a bias magnetic field from the outside in order to generate a larger magnetic field.
As shown in FIG. 2 (c), it is applied parallel to the bias magnetic field H DE the propagation direction of the surface acoustic wave, the internal magnetic, magnetic moment 2, aligned in the direction of the applied bias field H DE. On the other hand, on the surface of the magnetic material, the bias magnetic field H DE is combined with the magnetic field generated by the inverse magnetostriction effect. For example, the upward magnetic moment 3 is combined with the bias magnetic field H DE to become the slightly upward magnetic moment 4 of the angle H + . The downward magnetic moment 3 ′ of the adjacent mountain is combined with the bias magnetic field HDE to become a slightly downward magnetic moment 4 ′ of the angle H − . Similarly to the above, since the signs of the components perpendicular to the surface of the measured object of the magnetic moments 4 and 4 ′ are opposite, the leakage magnetic field Φ is generated.
以上のように、磁性体に弾性表面波を伝播することで、磁性体表面には漏洩磁界が発生するが、この漏洩磁界は弾性表面波の伝播に伴って、時間的に変動する。よって、この変動する漏洩磁界による磁束Φの時間変化を、例えば、漏洩磁界を取り巻くコイルにより、誘導起電力として検出することができる。 As described above, the surface acoustic wave is propagated to the magnetic material to generate a leakage magnetic field on the surface of the magnetic material. This leakage magnetic field varies with time as the surface acoustic wave propagates. Therefore, the time change of the magnetic flux Φ due to the changing leakage magnetic field can be detected as an induced electromotive force by, for example, a coil surrounding the leakage magnetic field.
次に、磁性体に弾性表面波を伝播して生じる漏洩磁界により磁性体内部の応力が評価できることを説明する。
磁性体に内部応力が作用していることで、逆磁歪効果により磁気弾性エネルギーが生じるが、この磁気弾性エネルギーは弾性表面波を伝播させて生じさせた磁気弾性エネルギーとは異なり、時間的変動のない静的なものである。しかしながら、機械的歪みは磁気歪を伴い、また逆に、磁気歪は機械的歪みを伴うので、弾性表面波による高周波磁界と磁性体内部の応力による静的磁界とが相互作用し、内部応力の大きさによって誘導起電力が変化すると考えられる。例えば、物体のヤング率は一般に定数ではなく、内部応力の大きさによって変化するので、弾性表面波が伝播して生じる漏洩磁界の大きさは、内部応力の大きさによって異なってくる。従って、磁性体表面の漏洩磁界の相違により、磁性体の応力状態を評価することができる。
Next, it will be described that the stress inside the magnetic body can be evaluated by a leakage magnetic field generated by propagating the surface acoustic wave to the magnetic body.
Magnetoelastic energy is generated by the inverse magnetostriction effect due to the internal stress acting on the magnetic material, but this magnetoelastic energy is different from the magnetoelastic energy generated by the propagation of the surface acoustic wave, and it is subject to temporal fluctuations. There is no static thing. However, mechanical strain is accompanied by magnetostriction, and conversely, since magnetostriction is accompanied by mechanical strain, the high-frequency magnetic field due to the surface acoustic wave interacts with the static magnetic field due to the stress inside the magnetic material, and the internal stress It is considered that the induced electromotive force changes depending on the magnitude. For example, since the Young's modulus of an object is generally not a constant and varies depending on the magnitude of internal stress, the magnitude of a leakage magnetic field generated by propagation of a surface acoustic wave varies depending on the magnitude of internal stress. Therefore, the stress state of the magnetic body can be evaluated based on the difference in the leakage magnetic field on the surface of the magnetic body.
次に、弾性表面波による応力評価装置の具体的な構成について説明する。
図３は、弾性表面波による応力評価装置１０の構成を示す模式図である。応力評価装置１０は、被測定物体２０の表面に弾性表面波Ｗを発生させる弾性表面波発生器１１と、印加磁界ＨDCを生じさせる印加磁界用コイル１２と、弾性表面波と印加磁界ＨDCにより生じた漏洩磁界を検出するための検出用コイル１３と、を備える。弾性表面波発生器１１は、例えば、超音波振動子１１ａと、超音波振動子１１ａを保持する保持台１１ｂとからなり、保持台１１ｂを被測定物２０上に載置した際に、超音波振動子１１ａの発生する超音波Ｗ0 を被測定物体２０の表面に所定の角度で入射するように、該保持台１１ｂに超音波振動子１１ａが保持されて構成されている。
Next, a specific configuration of the stress evaluation apparatus using surface acoustic waves will be described.
FIG. 3 is a schematic diagram illustrating a configuration of the stress evaluation apparatus 10 using surface acoustic waves. Stress evaluation apparatus 10 includes a surface acoustic wave generator 11 for generating a surface acoustic wave W on the surface of the object to be measured 20, the applied magnetic field H and the applied magnetic field coil 12 to produce a DC, applied a surface acoustic wave magnetic field H DC And a detection coil 13 for detecting the leakage magnetic field generated by the above. The surface acoustic wave generator 11 includes, for example, an ultrasonic transducer 11a and a holding table 11b that holds the ultrasonic transducer 11a. When the holding table 11b is placed on the object to be measured 20, ultrasonic waves are generated. ultrasonic W 0 generated by the oscillator 11a to be incident at a predetermined angle to the surface of the object to be measured 20, the ultrasonic transducer 11a is constituted held in the holder 11b.
弾性表面波発生器１１はパルス発信器１４と接続され、パルス発信器１４からの駆動パルスを受けて超音波Ｗ0 を発生する。また、印加磁界用コイル１２は、励磁コイル用電源装置１５と可変抵抗器１５ａと電流計１５ｂとに直列接続され、可変抵抗器１５ａにより励磁コイル用電源装置１５からの電流値を調整することで印加磁界の大きさを可変にすることができるように回路構成されている。検出用コイル１３は、必要により増幅器１６を介して測定器１７に接続され、検出用コイル１３で検出した誘導起電力を測定し、データ処理が行えるようになっている。なお、計測器１７はパルス発信器１４とも接続されており、弾性表面波発生器１１への駆動パルスの信号波形が取り込めるようになっている。 The surface acoustic wave generator 11 is connected to a pulse transmitter 14 and receives the drive pulse from the pulse transmitter 14 to generate an ultrasonic wave W 0 . The applied magnetic field coil 12 is connected in series to the exciting coil power supply 15, the variable resistor 15a, and the ammeter 15b, and the variable resistor 15a adjusts the current value from the exciting coil power supply 15. The circuit is configured so that the magnitude of the applied magnetic field can be made variable. The detection coil 13 is connected to a measuring instrument 17 through an amplifier 16 as necessary, and the induced electromotive force detected by the detection coil 13 is measured and data processing can be performed. The measuring instrument 17 is also connected to the pulse transmitter 14 so that the signal waveform of the driving pulse to the surface acoustic wave generator 11 can be taken in.
ここで、以上のように構成された応力評価装置１０による応力の測定評価の手順について説明する。
被測定対象物表面の任意の位置に検出用コイル１３を載せ、この検出用コイル１３の近傍に印加磁界用コイル１２を配置してバイアス磁界を印加する。被測定物２０の表面に、検出用コイル１３から所定の距離Ｌ0 離して、弾性表面波発生器１１を配置する。そして、印加磁界用コイル１２に所定の電流を流してバイアス磁界ＨDCを発生させ、被測定物表面から漏洩した磁界を検出用コイル１３により誘導起電力に変換して測定する。
Here, the procedure of the stress measurement evaluation by the stress evaluation apparatus 10 configured as described above will be described.
A detection coil 13 is placed at an arbitrary position on the surface of the object to be measured, and an applied magnetic field coil 12 is disposed in the vicinity of the detection coil 13 to apply a bias magnetic field. The surface acoustic wave generator 11 is disposed on the surface of the object to be measured 20 at a predetermined distance L 0 from the detection coil 13. Then, by supplying a predetermined current to the applied magnetic field coil 12 to generate a bias magnetic field H DC, measured by converting the induced electromotive force by the detecting coil 13 a magnetic field leaked from the workpiece surface.
図４は、弾性表面波発生器１１と検出用コイル１３との位置関係を模式的に示す図である。先ず、図４（ａ）に示すように、弾性表面波発生器１１を検出用コイル１３の向って左側に配置し、弾性表面波を左側から伝播させた場合の、各印加磁界に対する誘導起電力を測定する。次に、（ｂ）に示すように、弾性表面波発生器１１を検出用コイル１３の向って右側に配置して、弾性表面波を右から伝播させた場合の、各印加磁界に対する誘導起電力を測定する。つまり、弾性表面波の伝播方向に平行にバイアス磁界ＨDCを印加するが、バイアス磁界ＨDCの方向と弾性表面波の伝播方向とが同一方向の場合と、逆方向の場合とで、各印加磁界による誘導起電力を測定する。 FIG. 4 is a diagram schematically showing the positional relationship between the surface acoustic wave generator 11 and the detection coil 13. First, as shown in FIG. 4A, the induced electromotive force for each applied magnetic field when the surface acoustic wave generator 11 is arranged on the left side of the detection coil 13 and the surface acoustic wave is propagated from the left side. Measure. Next, as shown in (b), the induced electromotive force for each applied magnetic field when the surface acoustic wave generator 11 is disposed on the right side of the detection coil 13 and the surface acoustic wave is propagated from the right. Measure. That is, although applying a parallel bias magnetic field H DC the propagation direction of the surface acoustic wave, and if the propagation direction of the direction and the surface acoustic wave of the bias magnetic field H DC is in the same direction, in the case of reverse, the applied Measure the induced electromotive force due to the magnetic field.
バイアス磁界ＨDCの方向と弾性表面波の伝播方向とが同一方向の場合と、逆方向の場合とで、各印加磁界による誘導起電力を測定する理由を以下に説明する。
下記の実施例に示すように、バイアス磁界ＨDCの方向と弾性表面波の伝播方向とが同一方向の場合と、逆方向の場合とで、磁性体に残留応力が存在する場合には、その誘導起電力に大きな差が現れ、一方、磁性体に残留応力が存在しない場合には、その誘電起電力に差がない。このメカニズムは、現在までのところ十分解明されていないが、以下のように推定される。
すなわち、磁性体内部の応力による静的磁界とバイアス磁界ＨDCの方向が同じである場合には、静的磁界とバイアス磁界ＨDCとが合成されて大きな磁界となるので、磁性体の磁歪は増大され、磁気歪み曲線の勾配の大きな部位が動作点となって弾性表面波と相互作用するので誘導起電力は大きくなる。一方、磁性体内部の応力による静的磁界とバイアス磁界ＨDCの方向が逆向きである場合には、静的磁界とバイアス磁界ＨDCとが合成されて小さな磁界となるので、磁性体の磁歪は縮小され、磁気歪み曲線の勾配の小さな部位が動作点となって弾性表面波と相互作用するので誘導起電力は小さくなる。さらに、磁性体内部に応力が存在しない場合には、バイアス磁界ＨDCと合成される内部磁界は存在しないので、動作点の変動はなく、従って、誘導起電力の変化が生じない。
上記の効果は、バイアス磁界の方向が互いに逆である場合の効果であるが、同様の効果は、バイアス磁界ＨDCの方向に対する弾性表面波の伝播方向の違いによっても生じると推定される。以下に実施例を用いてこの事実を説明する。
And if the propagation direction of the direction and the surface acoustic wave of the bias magnetic field H DC is in the same direction, in the case of reverse, it explains why measuring the induced electromotive force by each applied magnetic field below.
As shown in the Examples below, and if the propagation direction of the direction and the surface acoustic wave of the bias magnetic field H DC is in the same direction, in the case of reverse direction, if there is residual stress in the magnetic body, that A large difference appears in the induced electromotive force. On the other hand, when there is no residual stress in the magnetic material, there is no difference in the dielectric electromotive force. Although this mechanism has not been sufficiently elucidated so far, it is presumed as follows.
That is, when the direction of the static magnetic field and the bias magnetic field H DC due to stress of the magnetic body portion are the same, since the static magnetic field and the bias magnetic field H DC is a major magnetic field are combined, the magnetostriction of the magnetic material The induced electromotive force is increased because the region where the gradient of the magnetostriction curve is increased becomes an operating point and interacts with the surface acoustic wave. On the other hand, if the direction of the static magnetic field and the bias magnetic field H DC due to stress of the magnetic body portion are opposite, because the static magnetic field and the bias magnetic field H DC is small magnetic field are combined, the magnetostriction of a magnetic material Is reduced, and a portion having a small gradient of the magnetostriction curve serves as an operating point and interacts with the surface acoustic wave, so that the induced electromotive force is reduced. Furthermore, when there is no stress inside the magnetic material, there is no internal magnetic field combined with the bias magnetic field HDC , so there is no fluctuation of the operating point, and therefore no change in induced electromotive force occurs.
The above effect is the effect of the direction of the bias magnetic field are opposite to each other, the same effect is also estimated to be caused by differences in the propagation direction of the surface acoustic wave with respect to the direction of the bias magnetic field H DC. This fact will be described below using examples.
印加磁界用コイル１２として、磁心にパーマロイを用い、電流１Ａ当たり６４００Ａ／ｍの磁界を発生できるＵ字型のコイルを用いた。検出用コイル１３には直径１ｍｍ、厚み８ｍｍのフェライトコアに、７００ターンの環状コイルを用いた。表面弾性波発生装置１１は、超音波振動子１１ａで発生した超音波を被測定物２０の表面の法線方向から角度ψ＝６５°傾斜させて入射するように構成し、被測定物２０の表面に達した縦波がレイリー波に変換されて、被測定物２０の表面を伝搬するようにした。
被測定物２０として、厚み５ｍｍ、幅７５ｍｍ、長さ３００ｍｍのフェライト系ステンレス鋼の市販試料と、同ステンレス鋼を８００℃で１時間熱処理して残留応力を除去した試料とを用いた。
As the applied magnetic field coil 12, a U-shaped coil that uses a permalloy for a magnetic core and can generate a magnetic field of 6400 A / m per current of 1 A was used. As the detection coil 13, a 700-turn annular coil was used for a ferrite core having a diameter of 1 mm and a thickness of 8 mm. The surface acoustic wave generator 11 is configured so that the ultrasonic wave generated by the ultrasonic transducer 11 a is incident at an angle ψ = 65 ° with respect to the normal direction of the surface of the object 20 to be measured. The longitudinal wave that reached the surface was converted to a Rayleigh wave and propagated on the surface of the DUT 20.
As the DUT 20, a commercially available ferritic stainless steel sample having a thickness of 5 mm, a width of 75 mm, and a length of 300 mm and a sample obtained by heat-treating the stainless steel at 800 ° C. for 1 hour to remove residual stress were used.
図４は実施例で用いた検出用コイルと弾性表面波発生器との位置関係を示す図である。図を見やすくするため、印加磁界用コイルは図示を省略している。
被測定物２０である平板試料の一端（図４では左端）を基準点（ｘ＝０）とし、その長手方向（図４の向って右方向）を＋ｘ方向と定義し、検出用コイル１３から弾性表面波発生器１１の一端までの距離Ｌ0 （図４参照）を固定して、弾性表面波の伝播方向をｘ方向と、逆向きの−ｘ方向の二方向で行った。なお、検出用コイルの位置を、平板試料の両端からの反射波の影響を考慮し、ｘ＝１１０ｍｍ〜１９０ｍｍまで１０ｍｍ刻みで、変化させて、誘導起電力の測定を行った。
FIG. 4 is a diagram showing the positional relationship between the detection coil and the surface acoustic wave generator used in the example. In order to make the drawing easier to see, the applied magnetic field coil is not shown.
One end (left end in FIG. 4) of the flat plate sample to be measured 20 is defined as a reference point (x = 0), and the longitudinal direction (right direction in FIG. 4) is defined as the + x direction. The distance L 0 (see FIG. 4) to one end of the surface acoustic wave generator 11 was fixed, and the propagation direction of the surface acoustic wave was performed in two directions, the x direction and the opposite −x direction. The induced electromotive force was measured by changing the position of the detection coil in increments of 10 mm from x = 110 mm to 190 mm in consideration of the influence of the reflected waves from both ends of the flat plate sample.
図５〜図７は、市販試料における誘導起電力の印加磁界依存性の測定結果を示すグラフで、図５の（ａ）〜（ｃ）はそれぞれ検出用コイルの位置が１１０ｍｍ、１２０ｍｍ、１３０ｍｍの各位置での測定結果、図６の（ａ）〜（ｃ）はそれぞれ検出用コイルの位置が１４０ｍｍ、１５０ｍｍ、１６０ｍｍの各位置での測定結果、図７の（ａ）〜（ｃ）はそれぞれ検出用コイルの位置が１７０ｍｍ、１８０ｍｍ、１９０ｍｍの各位置での測定結果を示している。各図において、縦軸は誘導起電力の大きさ（ｐｅａｋ−ｐｅａｋ，（ｍＶ））で、横軸は印加磁界の大きさ（Ａ／ｍ）である。実線（○）は、弾性表面波を＋ｘ方向に伝播させた時の誘導起電力の印加磁界依存性のグラフであり、点線（●）は弾性表面波を−ｘ方向に伝播させた時の誘導起電力の印加磁界依存性のグラフである。
各図から、検出用コイル１３の位置が何れの場合においても、印加磁界を大きくすると誘導起電力が生じており、被測定物の表面から漏洩した磁界が時間的に変化していることが分かる。また、市販試料においては、弾性表面波を＋ｘ方向に伝播させた時と−ｘ方向に伝播させた時の誘導起電力には大きな違いが生じていることが分かる。
5 to 7 are graphs showing measurement results of applied magnetic field dependence of induced electromotive force in commercially available samples. FIGS. 5A to 5C show the positions of the detection coils of 110 mm, 120 mm, and 130 mm, respectively. The measurement results at each position, (a) to (c) in FIG. 6 are the measurement results at the positions where the position of the detection coil is 140 mm, 150 mm, and 160 mm, respectively, and (a) to (c) in FIG. The measurement results at positions where the position of the detection coil is 170 mm, 180 mm, and 190 mm are shown. In each figure, the vertical axis represents the magnitude of the induced electromotive force (peak-peak, (mV)), and the horizontal axis represents the magnitude of the applied magnetic field (A / m). The solid line (◯) is a graph of the applied magnetic field dependence of the induced electromotive force when the surface acoustic wave is propagated in the + x direction, and the dotted line (●) is the induction when the surface acoustic wave is propagated in the −x direction. It is a graph of the applied magnetic field dependence of an electromotive force.
From each figure, it can be seen that, regardless of the position of the detection coil 13, an induced electromotive force is generated when the applied magnetic field is increased, and the magnetic field leaked from the surface of the object to be measured changes with time. . In addition, it can be seen that there is a great difference in the induced electromotive force between the surface acoustic wave propagated in the + x direction and the −x direction when the surface acoustic wave is propagated in the −x direction.
図８〜図１０は、熱処理して残留応力を除去した試料における誘導起電力の印加磁界依存性の測定結果を示した図で、図８の（ａ）〜（ｃ）はそれぞれ検出用コイルの位置が１１０ｍｍ、１２０ｍｍ、１３０ｍｍの各位置での測定結果、図９の（ａ）〜（ｃ）はそれぞれ検出用コイルの位置が１４０ｍｍ、１５０ｍｍ、１６０ｍｍの各位置での測定結果、図１０の（ａ）〜（ｃ）はそれぞれ検出用コイルの位置が１７０ｍｍ、１８０ｍｍ、１９０ｍｍの各位置での測定結果を示している。各図において、縦軸は誘導起電力の大きさ（ｐｅａｋ−ｐｅａｋ，（ｍＶ））で、横軸は印加磁界の大きさ（Ａ／ｍ）である。実線（○）は、弾性表面波を＋ｘ方向に伝播させた時の誘導起電力の印加磁界依存性を示すグラフであり、点線（●）は弾性表面波を−ｘ方向に伝播させた時の誘導起電力の印加磁界依存性のグラフである。
各図から、検出用コイル１３の位置が何れの場合においても、印加磁界を大きくすると誘導起電力が生じており、被測定物２０の表面から漏洩した磁界が時間的に変化していることが分かる。また、熱処理した試料において、弾性表面波を＋ｘ方向に伝播させた時と−ｘ方向に伝播させた時の各誘導起電力は、例えば、図７（ｃ）のように、略同じであることが分かる。このことから、この試料の残留応力はいずれの位置に置いても小さいと、評価することができる。
8 to 10 are diagrams showing measurement results of the applied magnetic field dependence of the induced electromotive force in the sample subjected to the heat treatment to remove the residual stress. FIGS. 8A to 8C show the detection coils respectively. The measurement results at positions 110 mm, 120 mm, and 130 mm, FIGS. 9A to 9C are the measurement results at positions 140 mm, 150 mm, and 160 mm, respectively. a) to (c) show the measurement results when the positions of the detection coils are 170 mm, 180 mm and 190 mm, respectively. In each figure, the vertical axis represents the magnitude of the induced electromotive force (peak-peak, (mV)), and the horizontal axis represents the magnitude of the applied magnetic field (A / m). The solid line (◯) is a graph showing the applied magnetic field dependence of the induced electromotive force when the surface acoustic wave is propagated in the + x direction, and the dotted line (●) is the graph when the surface acoustic wave is propagated in the −x direction. It is a graph of applied magnetic field dependence of the induced electromotive force.
From each figure, it can be seen that, regardless of the position of the detection coil 13, an induced electromotive force is generated when the applied magnetic field is increased, and the magnetic field leaked from the surface of the DUT 20 changes with time. I understand. Moreover, in the heat-treated sample, each induced electromotive force when the surface acoustic wave is propagated in the + x direction and when propagated in the −x direction is substantially the same as shown in FIG. 7C, for example. I understand. From this, it can be evaluated that the residual stress of this sample is small at any position.
また、図５〜７と図８〜１０とをそれぞれ比較すると、弾性表面波の伝播方向を＋ｘ方向にした時と−ｘ方向にした時の各誘導起電力の差が、熱処理した試料の方が小さいことが分かる。 Further, comparing FIGS. 5 to 7 and FIGS. 8 to 10 respectively, the difference in each induced electromotive force when the propagation direction of the surface acoustic wave is in the + x direction and in the −x direction is that of the heat-treated sample. Is small.
以上の実施例から分かるように、残留応力が存在すると、バイアス磁界ＨDCの方向に対する弾性表面波の伝播方向の違いによる誘導起電力の差は大きくなり、残留応力が無い場合には、この差は小さくなることが分かる。また、弾性表面波の伝播方向は一定とし、バイアス磁界ＨDCの方向を反転させても同様の結果が得られることを確認した。 As can be seen from the above examples, the residual stress is present, the difference between the induced electromotive force due to the difference in the propagation direction of a surface acoustic wave with respect to the direction of the bias magnetic field H DC is increased, if the residual stress is not, the difference It turns out that becomes small. Further, the propagation direction of a surface acoustic wave is kept constant, it was confirmed that the same results can be obtained by reversing the direction of the bias magnetic field H DC.
上記説明から理解されるように、本発明によれば、磁性体表面に弾性表面波を伝播させることで生じる漏洩振動磁界を利用して、磁性体内部に生じている応力を、正確、且つ、簡便に評価することができるので、各種の非破壊検査に利用すれば極めて有用である。 As can be understood from the above description, according to the present invention, the stress generated inside the magnetic body can be accurately determined using the leakage oscillating magnetic field generated by propagating the surface acoustic wave to the surface of the magnetic body. Since it can be easily evaluated, it is extremely useful if used for various nondestructive inspections.
１ 応力
２ 磁気モーメント（磁化）
３、３’ 隣り合う山の部分の磁気モーメント（磁化）
４，４’ バイアス磁界と磁気モーメントによる磁界との合成磁界
１０ 応力評価装置
１１ 弾性表面波発生器
１１ａ 超音波振動子
１１ｂ 保持台
１２ 印加磁界用コイル
１３ 検出用コイル
１４ パルス発信器
１５ 励磁コイル用電源装置
１５ａ 可変抵抗器
１５ｂ 電流計
１６ 増幅器
１７ 測定器
２０ 被測定物
1 Stress 2 Magnetic moment (magnetization)
3, 3 'Magnetic moment (magnetization) of adjacent mountain parts
4, 4 ′ Combined magnetic field of bias magnetic field and magnetic field by magnetic moment 10 Stress evaluation device 11 Surface acoustic wave generator 11a Ultrasonic vibrator 11b Holding base 12 Applied magnetic field coil 13 Detection coil 14 Pulse transmitter 15 Excitation coil Power supply device 15a Variable resistor 15b Ammeter 16 Amplifier 17 Measuring instrument 20 Device under test
Claims (6)
この漏洩振動磁界を測定することにより、磁性体内部に存在する応力を評価することを特徴とする、弾性表面波による応力評価方法。 A surface acoustic wave is propagated through the magnetic body and a bias magnetic field is applied in parallel to the propagation direction of the surface acoustic wave. A leakage oscillating magnetic field is generated by the inverse magnetostriction effect of the surface acoustic wave.
A stress evaluation method using a surface acoustic wave, characterized by evaluating a stress existing in a magnetic body by measuring the leakage oscillating magnetic field.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005243512A JP4631055B2 (en) | 2005-08-24 | 2005-08-24 | Stress evaluation method and apparatus using surface acoustic waves |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005243512A JP4631055B2 (en) | 2005-08-24 | 2005-08-24 | Stress evaluation method and apparatus using surface acoustic waves |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2007057397A JP2007057397A (en) | 2007-03-08 |
| JP4631055B2 true JP4631055B2 (en) | 2011-02-16 |
Family
ID=37921020
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005243512A Active JP4631055B2 (en) | 2005-08-24 | 2005-08-24 | Stress evaluation method and apparatus using surface acoustic waves |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4631055B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114659540B (en) * | 2022-03-29 | 2024-02-06 | 电子科技大学 | High-sensitivity surface acoustic wave vector magnetic field sensing system based on magnetic bias structure |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03205557A (en) * | 1989-05-12 | 1991-09-09 | Hitachi Constr Mach Co Ltd | Probe of ultrasonic microscope |
| JPH06313739A (en) * | 1993-03-31 | 1994-11-08 | Sakai Tekkosho:Kk | Sensor for measuring sound elastic stress using surface sh wave |
| JP2003279546A (en) * | 2002-03-26 | 2003-10-02 | Chuo Seisakusho Ltd | Inspection method for lap resistance welding part and device therefor |
| JP2003287565A (en) * | 2002-01-28 | 2003-10-10 | Japan Science & Technology Corp | Method for generating vibration magnetic field in magnetic substance, method for measuring distribution of effective magnetic field using the method, method for measuring magnetic body constant, and method for measuring residue strain in magnetic body |
-
2005
- 2005-08-24 JP JP2005243512A patent/JP4631055B2/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03205557A (en) * | 1989-05-12 | 1991-09-09 | Hitachi Constr Mach Co Ltd | Probe of ultrasonic microscope |
| JPH06313739A (en) * | 1993-03-31 | 1994-11-08 | Sakai Tekkosho:Kk | Sensor for measuring sound elastic stress using surface sh wave |
| JP2003287565A (en) * | 2002-01-28 | 2003-10-10 | Japan Science & Technology Corp | Method for generating vibration magnetic field in magnetic substance, method for measuring distribution of effective magnetic field using the method, method for measuring magnetic body constant, and method for measuring residue strain in magnetic body |
| JP2003279546A (en) * | 2002-03-26 | 2003-10-02 | Chuo Seisakusho Ltd | Inspection method for lap resistance welding part and device therefor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2007057397A (en) | 2007-03-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Hirao et al. | Electromagnetic acoustic transducers | |
| Kim et al. | Review of magnetostrictive patch transducers and applications in ultrasonic nondestructive testing of waveguides | |
| KR101073686B1 (en) | Segmented Magnetostrictive patch array transducer, apparatus of diagnosing structural fault having the same and method of operating the same | |
| KR100561215B1 (en) | Magnetostrictive Transducer for Generating and Sensing Elastic Ultrasonic waves, and Apparatus for Structural Diagnosis Using It | |
| Cho et al. | Megahertz-range guided pure torsional wave transduction and experiments using a magnetostrictive transducer | |
| JP6362533B2 (en) | Residual stress evaluation method and residual stress evaluation apparatus | |
| KR100573736B1 (en) | Transducer for Generating and Sensing Torsional Waves, and Apparatus and Method for Structural Diagnosis Using It | |
| Ma et al. | Excitation and detection of shear horizontal waves with electromagnetic acoustic transducers for nondestructive testing of plates | |
| JP6248183B2 (en) | Ultrasonic inspection apparatus and ultrasonic inspection method | |
| Sun et al. | Point-focusing of shear-horizontal wave using fan-shaped periodic permanent magnet focusing coils EMAT for plate inspection | |
| JP4203045B2 (en) | Magnetic deformation transducer using tail patch and elastic wave measuring device using it | |
| Dixon et al. | Texture measurements of metal sheets using wideband electromagnetic acoustic transducers | |
| JP2005077298A (en) | Electromagnetic ultrasonic probe, damage progression degree evaluation method and damage progression degree evaluation device of conductive material, and axial force measuring method and axial force measuring device of fastening bolt or rivet | |
| Ivanova et al. | Comparative measurements of the stress state in a rolled carbon steel using magnetic Barkhausen noise and ultrasonic method | |
| JP4631055B2 (en) | Stress evaluation method and apparatus using surface acoustic waves | |
| JP3299505B2 (en) | Ultrasonic flaw detection method using magnetostriction effect | |
| Hao et al. | Multi-belts coil longitudinal guided wave magnetostrictive transducer for ferromagnetic pipes testing | |
| Cobb et al. | Nonlinear ultrasonic measurements with EMATs for detecting pre-cracking fatigue damage | |
| Xu et al. | Research on the lift-off effect of generating longitudinal guided waves in pipes based on magnetostrictive effect | |
| Murayama | Non-Contact Stress Measurement during Tensile Testing Using an Emat for SH0-Plate Wave and Lamb Wave. | |
| Cai et al. | Nonlinear electromagnetic acoustic testing method for tensile damage evaluation | |
| KR101253965B1 (en) | Uni-directional ultrasonic transducer | |
| Tong et al. | Fabrication of a piezoelectric impact hammer and its application to the in-situ nondestructive evaluation of concrete | |
| JP4378019B2 (en) | Method of detecting deterioration of metal material by ultrasonic | |
| Zhang et al. | Improved Dynamic Magnetostriction measurement method based on M-EMAT for the characterization of residual strain |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20071005 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20091126 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20101019 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |