DE3017389A1 - Ultrasonic transducer with time variable magnetisation - has laminated yoke core generating magnetic field lines parallel to test specimen surface - Google Patents

Ultrasonic transducer with time variable magnetisation - has laminated yoke core generating magnetic field lines parallel to test specimen surface

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Publication number
DE3017389A1
DE3017389A1 DE19803017389 DE3017389A DE3017389A1 DE 3017389 A1 DE3017389 A1 DE 3017389A1 DE 19803017389 DE19803017389 DE 19803017389 DE 3017389 A DE3017389 A DE 3017389A DE 3017389 A1 DE3017389 A1 DE 3017389A1
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DE
Germany
Prior art keywords
magnetic field
field lines
generation
waves
ultrasonic transducer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
DE19803017389
Other languages
German (de)
Other versions
DE3017389C2 (en
Inventor
Gerhard Dipl.-Ing. 6630 Saarlouis Hübschen
Wilhelm Dipl.-Ing. 6638 Dillingen Repplinger
H.Jürgen Dipl.-Ing. 6680 Neunkirchen Salzburger
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Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
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Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
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Application filed by Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Priority to DE19803017389 priority Critical patent/DE3017389C2/en
Publication of DE3017389A1 publication Critical patent/DE3017389A1/en
Application granted granted Critical
Publication of DE3017389C2 publication Critical patent/DE3017389C2/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/22—Details, e.g. general constructional or apparatus details
    • G01N29/24—Probes
    • G01N29/2412—Probes using the magnetostrictive properties of the material to be examined, e.g. electromagnetic acoustic transducers [EMAT]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/042—Wave modes
    • G01N2291/0421—Longitudinal waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/042—Wave modes
    • G01N2291/0422—Shear waves, transverse waves, horizontally polarised waves

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

The ultrasonic transducer is used generating ultrasonic waves electrodynamically or magnetostrictively use most mostly static premagnetising of horizontal or vertical direction relative to the specimen surface. For the electromagnetic ultrasonic wave generation for material testing purposes is used a magnetic yoke and an ultrasonic transducer. The yoke has a laminated core and the generated magnetic field is time adjustable. The magnetic yoke is of such an arrangement that the magnetic field lines extend parallel to the testing specimen surface. The transmission and receiving of the ultrasonic waves is synchronised with the timing of the magnetic field. For generation of longitudinal waves by electrodynamic method and for generation of transverse waves by magnetostriction the wires of the ultrasonic transducer are arranged horizontal to the surface and perpendicular to the magnetic field lines.

Description

Ultraschallwandler mit zeitlich verarderlicher Magnetisierung zur Erzeugung bestimmter Wellenarten Bei Ultraschalllwandlern, die auf elektrodynamische oder magnetostriktive Art und Weise Ultrasihall (US) erzeugen, wird meist horizontal oder vertikal zur Prüflingsober@läche gerichtete statische Vormagnetisierung benutzt /1-7/. In einigen Fällen ist ein horizontales Maynetfeld über größere Entfernungen besonders interessant (magnetostriktive Anregung von SH-Wellen, elektrodynamische Anregung von Normalkräften). Bisher werden zur Erzeugung von horizontalen Magnetreldern Dauermagnete oder Elektromagnete mit Gleichstromspeisung bzw. gepulster Gleichspannung benutzt.Ultrasonic transducers with temporally verarderlicher magnetization for Generation of certain types of waves In ultrasonic transducers that rely on electrodynamic or magnetostrictive way of generating ultrasound (US) is mostly horizontal or static premagnetization directed vertically to the test object surface is used / 1-7 /. In some cases there is a horizontal Maynet field over longer distances particularly interesting (magnetostrictive excitation of SH waves, electrodynamic Excitation of normal forces). So far, the generation of horizontal magnetic fields Permanent magnets or electromagnets with direct current supply or pulsed direct voltage used.

Statische Magnetfelder parallel zur Oberlfläche sind jedoch bei großem Verhältnis von Prüfstückdicke zu Pol abstand schlecht zu realisieren und führen zu einen geringen Wirkungsgrad.Static magnetic fields parallel to the surface are, however, at large The ratio of test piece thickness to pole spacing is difficult to implement and manage too low efficiency.

Die Magnetfelder dringen dann tiei in das Material ein. Die Feldstärke an der Oberfläche des Prüflings ist daher ralativ gering.The magnetic fields then penetrate deeply into the material. The field strength on the surface of the test object is therefore relatively low.

Zur Ultraschallanregung ist jedoch nur dds Feld an der Oberfläche von Interesse.For ultrasonic excitation, however, there is only dds field on the surface of interest.

Wandler mit statisches Magnetfeld, insbesondere Wandler mit Dauermagneten können bei hohen Feldern kauiii bewegt werden und erschweren damit die Handhabung der Prüfköpfe. Al weiterer Nachteil kann sich die eventuelle Magnetisierung der Prüfkörper erweisen.Converters with a static magnetic field, especially converters with permanent magnets can be moved kauiii in high fields and thus make handling more difficult of the probes. Al further disadvantage can be the possible magnetization of the Prove test specimen.

Zur Anregung bestimmter US-Wellen iii leirfähigen Prüfkörpern wird daher erfindungsgemtiß ein horizontales Magnetfeld an der Oberfläche durch die Verwendung eines zeitlich verandert @@ Magneteldes erzeugt.For the excitation of certain US waves iii conductive test bodies is therefore, according to the invention, a horizontal magnetic field on the surface through the use a temporally changed @@ magnetic field generated.

Durch die .fortwährende-Anderung des Magnetfeldes werden die Magnetfeldlinien an die Oberfläche gedrängt (Skin-Effekt).Due to the continuous change in the magnetic field, the magnetic field lines become pushed to the surface (skin effect).

Der Prüfkopf läßt sich nun auch bei hohen Oberflächenfeldstärken gut bewegen. Weiterhin kann das Prüfkopfvolumen bei gleicher Oberflächenfeldstärke verrringert werden.The test head can now be operated well even with high surface field strengths move. Furthermore, the test head volume can be reduced with the same surface field strength will.

Das zeitlich veränderliche Magnetfeld kann mit Luftspulen, in direkter elektrischer Durchströmung des Prüfkörpers oder mit einem Magnetjoch erzeugt werden. Das Magnetjoch mu-R für geringe Magnetisierungsverluste aus magnetisch leitenden Blechen bestehen, die elektrisch gegeneinander is.oliert sind.The time-varying magnetic field can be made with air coils, in direct electrical flow through the test body or with a magnetic yoke. The magnet yoke mu-R for low magnetization losses from magnetically conductive There are metal sheets that are electrically ins.oliert against each other.

Die Blechdicke wird nach den Regeln der Wechselstromtransformatoren bestimmt.The sheet thickness is determined according to the rules of alternating current transformers certainly.

Zum Empfangen und Senden von US-Wellen ist es erfindungsgemäß notwendig, das Senden und Empfangen mit der Magnetisierung zu synchronisieren. Es wird bei elektrodynamischen Wandlern dann gesendet und empfangen, wenn die Oberflächenfeldstärke ein Maximum besitzt.To receive and transmit US waves, it is necessary according to the invention, synchronize sending and receiving with magnetization. It will be at electrodynamic transducers are then sent and received when the surface field strength has a maximum.

Bei magnetostriktiven Wandlern wird dann gesendet und empfangen, wenn die änderung der Magnetostriktion mit der Magnetisierungsfeldstärke am größten ist. Die Synchronisierung kann mit Hilfe des Erregerstromes des Magneten durchgeführt werden. Die Zeitdauer, die für das Senden und Empfangen benötigt wird (Schalllaufweg), bestimmt die maximale Frequenz der Magnetisierung. Man ist bestrebt, bei'möglichst konstanten (quasistatischem) Feld zu senden und zu Empfangen. Das bedeutet, daß während der US-Prüfung die änderung der Feldstärke (Induktion) relativ langsam vonstatten geht.In the case of magnetostrictive converters, it is sent and received when the change in magnetostriction is greatest with the magnetization field strength. The synchronization can be carried out with the help of the excitation current of the magnet will. The time required for sending and receiving (sound path), determines the maximum frequency of magnetization. One strives to do as much as possible send and receive constant (quasi-static) field. It means that the change in field strength (induction) occurs relatively slowly during the US test goes.

Beispiel: Schallaufweg 400 mm, Zeitdauer ca. 125 ps (bei Schubwelle in Stahl), Erregerfrequenz 20 Hz Sinus, Magnetfeld-änderung während der US-Prüfung ca. 0,1 °/oo US Wiederholungsfrequenz 40 Hz.Example: sound travel 400 mm, duration approx. 125 ps (with shear wave in steel), excitation frequency 20 Hz sine, magnetic field change during the US test approx. 0.1 ° / oo US repetition frequency 40 Hz.

Wird mit Wechselstrom als Erreyung gearbeitet, sind die Anordnungen zur Ultraschallanregung gleichzeitig geeignet, magnetinduktiv Barkhausen-Rauschen aufzunehmen (nur bei ferromagnetischen Materialien) Literatur /1/ R.B. Thompson Noncontact transducers 1973 Ultrasonics Symposium Proceedings, IEEE, New York 1973 /2/ R.E. Beissner Electromagnetic-Acoustic transducers. A survey of the state-ofthe-art.If alternating current is used as the Erreyung, the arrangements are suitable for ultrasonic excitation at the same time, magnetic induction Barkhausen noise record (only for ferromagnetic materials) Literature / 1 / R.B. Thompson Noncontact transducers 1973 Ultrasonics Symposium Proceedings, IEEE, New York 1973/2 / R.E. Beissner Electromagnetic-Acoustic transducers. A survey of the state-of-the-art.

Nondestructive Testing Information Analysis Center (NTIAC), San Antonio, Texas, Januar 1976 /3/ C.F Vasile, R.B. Thompson Periodic magnet non-contact electromagnetic acoustic wave transducer - therory and application. Nondestructive Testing Information Analysis Center (NTIAC), San Antonio, Texas, January 1976/3 / C.F Vasile, R.B. Thompson Periodic magnet non-contact electromagnetic acoustic wave transducer - therapy and application.

1977 Ultrasonics Symposium Proceedings, IEEE, New York, Cat. 1977 Ultrasonics Symposium Proceedings, IEEE, New York, Cat.

# 77 CH1264-1SU /4/ H. Shimizu, A.J. Bahr Improved design for non-contacting electromagnetic acoustic transducers. # 77 CH1264-1SU / 4 / H. Shimizu, A.J. Bahr Improved design for non-contacting electromagnetic acoustic transducers.

1977 Ultrasonics Symposium Proceedings, IEEE, New York, Cat. 1977 Ultrasonics Symposium Proceedings, IEEE, New York, Cat.

tt77 CH1264-lSU /5/ R.B. Thompson A model for the electromagnetic generation of ultrasonic gui ded waves in ferromagnetic metal polycrystals. tt77 CH1264-ISU / 5 / R.B. Thompson A model for the electromagnetic generation of ultrasonic gui ded waves in ferromagnetic metal polycrystals.

IEEE Trans. Sincs &Ultrasonics, 25 (1), Jan. 1978 /6/ R.B. Thompson New config'urations for the electromagnetic generation of SH-waves in ferromagnetic materials. IEEE Trans. Sincs & Ultrasonics, 25 (1), Jan. 1978/6 / R.B. Thompson New configurations for the electromagnetic generation of SH-waves in ferromagnetic materials.

1978 Ultrasonics Symposium Proceedings. IEEE, New York, Cat. 1978 Ultrasonics Symposium Proceedings. IEEE, New York, Cat.

+ 78 CH1344-lSU /7/ W. Mohr, W. Repplinger Elektrodynamische berührungslose Anregung freier Ultraschallwelle Materialprüfung, 20 (1978), 4 Materialprüfung, ?° (1978), 6 L e e r s e i t e + 78 CH1344-lSU / 7 / W. Mohr, W. Repplinger Electrodynamic contactless Excitation of free ultrasonic waves Materialprüfung, 20 (1978), 4 Materialprüfung, ? ° (1978), 6 L e r s e i t e

Claims (4)

PATENTANSPRUCHE 1. Verfahren zum Erzeugen eines Magnetfeldes für die elektromagneti sche Ultraschall erzeugung für Materialprüfung mittels US unter Verwendung eines Magnetjoches und eiries Uitraschal lwandlers dadurch gekennzeichnet, daß a) ein lammel lierter Jochkern verwendet wird b) das Magnetfeld zeitlich veränderlich erzeugt wird c) das Magnetjoch derart angeordnet ist, daß die Feldlinien parallel zur Prüfkörperoberfläche liegen d) und das Senden und Empfangen der Ultraschallwellen mit dem zeitlichen Verlauf des Magnetfeldes synchronisiert wird. PATENT CLAIMS 1. Method for generating a magnetic field for the electromagnetic ultrasound generation for materials testing using US under Use of a magnetic yoke and egg-shaped Uitraschal converter characterized in that that a) a lated yoke core is used b) the magnetic field is variable over time c) the magnet yoke is arranged in such a way that the field lines are parallel to the test body surface are d) and the sending and receiving of the ultrasonic waves is synchronized with the temporal course of the magnetic field. 2. Verfahren nach Anspruch 1 dadurch gekennzeichnet, daß zur Erzeugung von Longitudinalwellen auf elektrodynamischem Wege sowie zur Erzeugung von Transversalwellen durch Magnetostriktion die Drähte des US-Wandlers horizontal zur Oberfläche und 900 zu den Magnetfeldlinien angeordnet sind (Fig. 1) 2. The method according to claim 1, characterized in that for generation of longitudinal waves by electrodynamic means as well as for the generation of transverse waves by magnetostriction the wires of the US transducer are horizontal to the surface and 900 are arranged to the magnetic field lines (Fig. 1) 3. Verfahren nach Anspruch 1 dadurch gekennzeichnet, daß bei ferromagnetischen Werkstoffen zur Erzeugung von Transversalwellen, die senkrecht zur Einfallsebene polarisiert sind, die Drähte, des Wandlers horizontal zur Oberfläche und parallel zu den Magnetfeldlinien angeordnet sind.3. The method according to claim 1 characterized in that with ferromagnetic materials to the Generation of transverse waves that are polarized perpendicular to the plane of incidence, the wires, of the transducer horizontal to the surface and parallel to the magnetic field lines are arranged. (Fig. 2) (Fig. 2) 4. Verfahren nach Anspruch 1 - 3 unter Verwendung von Wandlern nach Patent Nr. 26 55 804.3-524. The method according to claim 1-3 using transducers according to patent No. 26 55 804.3-52
DE19803017389 1980-05-07 1980-05-07 Method for generating ultrasound Expired DE3017389C2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19803017389 DE3017389C2 (en) 1980-05-07 1980-05-07 Method for generating ultrasound

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Application Number Priority Date Filing Date Title
DE19803017389 DE3017389C2 (en) 1980-05-07 1980-05-07 Method for generating ultrasound

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DE3017389A1 true DE3017389A1 (en) 1981-11-12
DE3017389C2 DE3017389C2 (en) 1984-11-15

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109507280A (en) * 2018-11-12 2019-03-22 中国计量大学 A kind of exchange saturated magnetization device for low frequency electromagnetic detection

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4101942A1 (en) * 1990-01-31 1991-08-08 Mannesmann Ag METHOD AND TESTING DEVICES FOR TESTING FERROMAGNETIC WORKPIECES BY MEANS OF ULTRASONIC WAVES
DE4223470C2 (en) * 1992-07-16 1995-10-05 Fraunhofer Ges Forschung Ultrasonic probe

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2643601C3 (en) * 1976-09-28 1979-03-08 Hoesch Werke Ag, 4600 Dortmund Method for non-destructive material testing with ultrasound using an electrodynamic sound transducer
DE2655804B2 (en) * 1976-12-09 1979-05-10 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V., 8000 Muenchen Electrodynamic ultrasonic wave transducer
DE2652085C3 (en) * 1976-11-16 1979-11-15 Hoesch Werke Ag, 4600 Dortmund

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2643601C3 (en) * 1976-09-28 1979-03-08 Hoesch Werke Ag, 4600 Dortmund Method for non-destructive material testing with ultrasound using an electrodynamic sound transducer
DE2652085C3 (en) * 1976-11-16 1979-11-15 Hoesch Werke Ag, 4600 Dortmund
DE2655804B2 (en) * 1976-12-09 1979-05-10 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V., 8000 Muenchen Electrodynamic ultrasonic wave transducer

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
1978 Ultrasonics Symposium Proceedings, IEEE Cat. No 78CH1344-1SU, S. 374-478 *
DE-Z.: materialprüfung, Bd. 20, 1978, Nr. 4, April, S. 147-154 *
US-Z.: IEEE Transactions on Sonics and Ultrasonics, Vol. SU-25, No. 1, Jan. 1978, S. 7-15 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109507280A (en) * 2018-11-12 2019-03-22 中国计量大学 A kind of exchange saturated magnetization device for low frequency electromagnetic detection

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DE3017389C2 (en) 1984-11-15

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