High energy, low frequency, ultrasonic transducer

Patent · Sat Jan 01 00:00:00 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 (United States)
• 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

energy
frequency
ultrasonic
transducer
wide
bandwidth
generate
nondispersive
extensional
pulsed
acoustic
pressure
waves
concrete
reinforced
rods
tendons
wave
propagation
distance
limited
double
length
rod
impedance
matched
maximum
transfer
efficiency
approximately
60
percent
depending
type
active
elements
input
example
mj
reflections
occur
changes
wavelength
diameter
reduction
reflect
phase
reversed
echo
compared
reflection
incremental
increase
signal
processing
stored
waveform
permits
reconstruction
echoes
image
inspection
40
foot
architectural
reinforcements
structural
supporting
bridges
dams
wide band
acoustic pressure
wave propagation
pressure waves
structural support
acoustic impedance
signal processing
ultrasonic transducer
acoustic energy
active element
pressure wave
active elements
input energy
propagation distance
signal process
wide bandwidth
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