Phase Array Ultrasound Basics
What’s this????
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Amplitude
Amplitude
Traditional UT A-scan - straight beam
measures time (sound path): Depth
Time (depth)
Time (depth)
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Traditional UT angle beam –
measures time (sound path-S) – wedge creates mechanical delay
Trigonometry can also reveal depth (d) and surface distance index (I)
I
S
d
Resulting
Shear Wave
Play video link
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Phased Array UT uses electronic delays on groups of
elements call Virtual Probes to create the desired
sound angle and shape (focal point)
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We use a combination of focused angle beams
Focal Point
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Each Virtual Probe has an A-scan
A-Scan
VPA #36
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Several Virtual Probes can be used
in a single transducer to maintain
optimum inspection coverage over the weld zone
Virtual Probe
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Phase Array Ultrasound Uses Material Velocity
and the Sound Angle to generate a 3D image
by compiling all A-Scans together into a colour map
S-Scan Cross Section
(width x depth)
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Phased Array Data Presentation
Full Length Scan
C-Scan Top View (width x length)
S-Scan Cross Section (width x depth)
A-Scan
(amplitude + Time)
B-Scan Side view (depth x length)
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B-Scan presentation – Side View (depth)
Play video link
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C-Scan presentation – Top View (index)
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Beam focusing and increased Megahertz
improves resolution
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The Price of High Resolution / Acquisition
small
defects)
Scan SPEED!!!!
(finding
Missed DATA
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Phased Array True Depth Sensitivity Calibration
Normalizes identical flaw signals
across all beams at a constant depth.
Un-calibrated : Lower signal from red
arrow due to sound path distance
Calibrated :
equal amplitude across all beams
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Time Corrected Gain (TCG) Calibration
Normalizes identical flaw signals
across all beams at varying range (depth).
Un-calibrated : Lower signal received
due to increased sound path distance
Calibrated :
equal amplitude across all depth within TCG
=
= Reject Level
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SpaceX NDE PAUT report
A typical report shows equipment setting and calibration data on
the first page,
with full length scans and close-up views of individual defects
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Reporting
Header and User Fields
WO # / intended flight or S/N
part name
Probe placement (Root/Crown) and
scan start location (Q4/AFT/FWD)
Transducer S/N
to be included
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Reporting
Setup/TCG
Time Corrected Gain – 3 points minimum
required across an area
double the thickness or 1 full skip
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Reporting
Indication Table
Indication location
(from zero datum/Q4)
Index from
centerline
Amplitude
Depth
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Reporting
Screen Shot B-Scan
Side view
Depth
Max Amplitude
within Pink Box
Scan location from start point
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Reporting
Index -/+ of center
Screen Shot C-Scan
Top View
Scan location from start point
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Reporting
Screen Shot S-Scan
Cross Section View
Distance between
measurement cursors
(indication/hook height)
Depth
Red and blue
measurement cursors
Index -/+ of center
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PHASED ARRAY UT BASICS
If you think that is easy?
TRY THE ADVANCED VERSION
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