High energy, low frequency, ultrasonic transducer

Patent · Sat Jan 01 04:00:00 EST 2000

OSTI ID:873185

Brown, Albert E ^[1]

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1. Hayward, CA

A wide bandwidth, ultrasonic transducer to generate nondispersive, extensional, pulsed acoustic pressure waves into concrete reinforced rods and tendons. The wave propagation distance is limited to double the length of the rod. The transducer acoustic impedance is matched to the rod impedance for maximum transfer of acoustic energy. The efficiency of the transducer is approximately 60 percent, depending upon the type of active elements used in the transducer. The transducer input energy is, for example, approximately 1 mJ. Ultrasonic reflections will occur at points along the rod where there are changes of one percent of a wavelength in the rod diameter. A reduction in the rod diameter will reflect a phase reversed echo, as compared with the reflection from an incremental increase in diameter. Echo signal processing of the stored waveform permits a reconstruction of those echoes into an image of the rod. The ultrasonic transducer has use in the acoustic inspection of long (40+foot) architectural reinforcements and structural supporting members, such as in bridges and dams.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 6109109
• OSTI ID: 873185
• Country of Publication: United States
• Language: English

Related Subjects

/73/367/
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acoustic
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acoustic impedance
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active
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approximately
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signal processing
stored
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supporting
tendons
transducer
transfer
type
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ultrasonic transducer
wave
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wide
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