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  <doc>
    <id>35511</id>
    <completedYear/>
    <publishedYear>2016</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>1</pageFirst>
    <pageLast>8</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>conferenceobject</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Focusing air-coupled ultrasonic transducers based on ferroelectrets</title>
    <abstract language="eng">Rising importance of composite lightweight structures in aircraft and automobile industries increases the demand on reliable non-destructive testing methods for these structures. Air-coupled ultrasonic testing emerged to suit these requirements as it does not require any liquid coupling medium. In conventional air-coupled ultrasonic transducers, matching layers are used in order to decrease the impedance mismatch between transducer and air. Matching layers can be omitted by using ferroelectrets, which are charged cellular polymers having ferroelectric and piezoelectric properties. Especially a low Young’s modulus, low density and low sound velocity of cellular polypropylene (cPP) are properties being required for well-matched air-coupled ultrasonic transducers.&#13;
In our contribution we show recent enhancements of cPP transducers resulting in focused sound fields and thus improved lateral sensitivity. The influence of different transmitter apertures was evaluated using measurements of the emitted sound field. Further we show a transmission of a test specimen of carbon-fiber-reinforced plastic (CFRP) containing artificial damages. Results of focused transducers were compared to planar ferroelectret transducers, as well as to conventional air-coupled transducers.</abstract>
    <parentTitle language="eng">Proceedings 19th World Conference on Non-Destructive Testing</parentTitle>
    <identifier type="urn">urn:nbn:de:kobv:b43-355116</identifier>
    <identifier type="url">http://www.ndt.net/search/docs.php3?showForm=off&amp;id=19453</identifier>
    <enrichment key="eventName">19th World Conference on Non-Destructive Testing 2016</enrichment>
    <enrichment key="eventPlace">München, Germany</enrichment>
    <enrichment key="eventStart">13.06.2016</enrichment>
    <enrichment key="eventEnd">17.06.2016</enrichment>
    <licence>Creative Commons - Namensnennung 3.0</licence>
    <author>Florian Schadow</author>
    <author>Mate Gaal</author>
    <author>Jürgen Bartusch</author>
    <author>E. Dohse</author>
    <author>Enrico Köppe</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Air-coupled ultrasonic testing</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Ferroelectrets</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Cellular polypropylene</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Focused sound fields</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Focused transducers</value>
    </subject>
    <collection role="ddc" number="620">Ingenieurwissenschaften und zugeordnete Tätigkeiten</collection>
    <collection role="literaturgattung" number="">Verlagsliteratur</collection>
    <collection role="fulltextaccess" number="">Datei für die Öffentlichkeit verfügbar ("Open Access")</collection>
    <collection role="unnumberedseries" number="">Wissenschaftliche Artikel der BAM</collection>
    <thesisPublisher>Bundesanstalt für Materialforschung und -prüfung (BAM)</thesisPublisher>
    <file>https://opus4.kobv.de/opus4-bam/files/35511/tu2g1.pdf</file>
  </doc>
</export-example>
