Study on the Doppler Method to Detect Metal Fault | Chapter 4 | Advances and Trends in Physical Science Research Vol. 2
The study
deals with the interaction of ultrasound with metals discovered an unusual
phenomenon. Microwave sensor indicates
fluctuations of electric
surface conductivity when
exposed to elastic ultrasonic vibrations in metal
objects. The defective area is by a content of microdefects of the type
"the mouth of the cracks". They are known as the field of
"acoustic activity" the method of Acoustic Emission (AE). The high
coefficient of phase modulation of the reflected field allows you to indicate the Doppler signal is
useful for 6-30
dB over the
noise from a
distance of 70-180
mm. The phenomenon is called "of
Gorbunov effect". It has been successfully used as remote non-destructive
testing method is ultrasonic methods of flaw detection, acoustic emission. A
semiconductor detector responds to the
amount of incident
and reflected waves,
registering the change
in reflection coefficient. When
injected into the area of the surface that differ in conductivity from the
previous one can identify cracks the size of a quarter wavelength. It has been
successfully used as remote non-destructive testing method that replaces the
ultrasonic methods of flaw detection, acoustic emission. While testing a
fragment of the steam-pipe destroyed
during operation due to flooding,
our device allowed to indicate these defects when the external surface
of the steam pipe is excited by ultrasound. The microwave sensor at this time
irradiated the outside surface of the steam. Rrevealing that the new device is
able to reconsider the defectoscopy of the inne-surface of the steam pipe by
chemical etching method of the inner-surface with scrutinizing by a contrast
agent, a microscope, an x-ray flaw detector.
Another
version of the test of the new device relates to the indication of the quality
ofzirconium tubes (used for heat Emitting Elements (TVEL) in thermal nuclear
power plants). Result revealed that the
manufactured tubes should be rejected due to the appearance of
"punctures", "sticking", scratches, micro-cracks. All these
defects can be determined by optical methods using special microscopes with
electronic video recording,
software. The time
taken for this
study takes up
to ten minutes.
The device, reveals the defects in 2-3 seconds.
Biography of author(s)
Kapranov Boris
Tomsk Polytechnic University, Tomsk, Russia.
Tomsk Polytechnic University, Tomsk, Russia.
Sutorikhin
Vladimir
Remote Indicators of Active Defects Ltd., Tomsk, Russia.
Remote Indicators of Active Defects Ltd., Tomsk, Russia.
Read full article: http://bp.bookpi.org/index.php/bpi/catalog/view/25/62/150-1
View Volume: https://doi.org/10.9734/bpi/atpsr/v2
View Volume: https://doi.org/10.9734/bpi/atpsr/v2
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