Advanced Phased Array Techniques for Defect
Identification & Characterization
Brandon Reitz
NDT TECHNOLOGY MANAGER
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
ADVANCED PHASED ARRAY TECHNIQUES FOR DEFECT IDENTIFICATION & CHARACTERIZATION
Agenda
1
Phased Array &
Conventional UT
2
Advanced
Techniques
3
Case Studies
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Phased Array & Conventional UT
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Phased Array
Ultrasonic Testing
• Originally developed as a
complementary application to
conventional UT
• Utilize time delays to multiple
elements to focus and steer
the sound beam
• Collects and visualizes data
convention UT cannot - weld
inspection, bond testing,
thickness mapping, crack
detection
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Phased Array vs Conventional UT
Phased Array
10 MHz
1.51” coverage (38.4 mm)
Electronically controlled
beam properties
Conventional
7.5 MHz
0.187” coverage (5 mm)
Fixed beam characteristics
2.0”
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Phased Array vs Conventional UT
Phased Array
7.5 MHz – 32 Element
40-75° Sectoral
Full coverage of the weld
Conventional
5 MHz – 0.500”
60°
Requires rastering
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Data Imaging Comparison
1.9” (48 mm) Demonstration Block
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Data Imaging Comparison
Flat Bottom Holes
Round Bottom Holes
Conventional UT
Phased Array UT
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Data Imaging Comparison
Conventional UT
0.375” UT Linear
0.250” x 0.050” Resolution
Phased Array UT
64 Element
0.039” x 0.039” Resolution
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Phased Array Benefits
• Resolution: Quantifiable approach for differentiating between manufacturing
defects and service-related damage
• Speed: Despite the mechanical system used, scanning with phased array is faster
than a single UT probe by offering greater coverage.
• Flexibility: Setups are modular, and typically, more component-gemoetry flexibility
is available.
• Inspection angles: Various angles can be used depending on the requirements and
the array configuration.
• Data imaging: Showing a “true depth” image of defects is much easier to interpret
than a waveform.
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Advanced Techniques
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Tri-Lateral Phased Array
•
Robotic-enabled ultrasonic testing technique
•
On-stream, base metal inspection of carbon steel and low alloy
equipment
•
Identifies and characterizes insidious damage mechanisms in
caustic environments
•
Wet H2S Damage (HIC, SOHIC, SSC), HTHA, environmental
cracking, H blisters
•
Three-beamset configuration
•
Linear: probe with 0Ǎand 30Ǎbeam sets
•
Lateral: probe with 45Ǎfixed steering with passive plane
focalization
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
0° Linear
30° Linear
45° Lateral
TriLateral
Phased
Array
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Advanced Data Acquisition Techniques
Full Matrix Capture (FMC): each element in
the phased array probe is pulsed individually
while all elements receive the signals, creating
a matrix of elementary A-scans
Source: https://www.olympus-ims.com/en/applications/using-the-totalfocusing-method-to-improve-phased-array-ultrasonic-imaging/
Plane Wave Imaging (PWI): all or groups
elements are excited simultaneously (like
conventional phased array) while the returning
signals are “listened to” by all elements
Source: https://pubmed.ncbi.nlm.nih.gov/24402899/
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Advanced Data Imaging Techniques
Total Focusing Method: Reconstructs the
elementary A-scans generated from FMC or
PWI pixel by pixel, differentiating areas of high
amplitude (defect) from areas of low amplitude
Phase Coherence Imaging (PCI): uses the
phase distribution of normalized A-scans to
identify high levels of coherence, advantageous
for identifying small defects in noisy materials
Source: https://www.olympus-ims.com/en/white-papers/phasecoherence-imaging-for-flaw-detection/
Source: https://www.olympus-ims.com/en/insight/tfm-resources/
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Processing PCI Data
In standard TFM both
Phase and Amplitude are
calculated into the
resulting images
Raw data is collected
through the normal FMC
process
Amplitude is removed
leaving only the Phase
information to process
into a TFM image
Amplitude
Delay-and-Sum (TFM)
Raw FMC A-Scan
Phase
(PCI)
Manual UT
Phased Array
Data Imaging
Comparison
ID-connected cracking in a single
V carbon steel weld
TFM
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
PCI
Contains confidential information. Do not distribute.
Advantages of TFM/PCI
•
Increased POD
•
•
High resolution imaging without the need to
configure the focusing or aperture
Improved sizing, sensitivity, and
characterization of defects
•
Basic image is easier to understand
•
Optimal focusing everywhere in the image
•
Better geometric positioning
•
Imaging of stacked defects
HIC - Tri-Lateral – 10 MHz - 64 Element Probe
TFM
PCI
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Disadvantages of TFM/PCI
•
Low production rate
•
Difficult to automate
•
Large data file sizes requiring
significant storage and processing
power
•
Difficult to implement on complex
geometries
•
Flaw detection is very dependent
proper setup
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Case Studies
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Condensate Storage Vessel Shell
Challenge
Out of service vessel, used for technician qualification
• 2002: HIC & H blisters first identified (manual SWUT)
• Annual inspection schedule following FFS
• Slow growth and stepwise cracking found over time
• 2020: Vessel removed from service
Solution
Deployment of TriLat robotically
FMC with TFM and PCI Imaging
Result
No step-wise cracking.
Extensive laminations, but no HIC indications
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Defect 1
Defect: 1
Depth: 4.5mm from OD
Dimension: 13mm x 63mm
Characterization: Lamination
Tri-Lateral PAUT
0°L/30°L/45°S
C-Scans
Defect 2
Defect: 2
Depth: 6.98mm from OD
Dimension: 11mm x 66mm
Characterization: Hydrogen Blister
Defect: 3
Depth: 4.29mm from OD
Dimension: 10mm x 61mm
Characterization: Lamination
Defect 3
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
FMC - TFM
FMC - PCI
Defect: 1
Depth: 4.5mm from OD
Dimension: 13mm x 63mm
Characterization: Lamination
FMC Data
TFM 0° (L-L)
PCI 0° (L-L)
Defect: 2
Depth: 6.98mm from OD
Dimension: 11mm x 66mm
Characterization: Hydrogen Blister
Defect: 3
Depth: 4.29mm from OD
Dimension: 10mm x 61mm
Characterization: Lamination
FMC - TFM
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
FMC - PCI
Amine Recycle Gas Scrubber
Challenge
Non-intrusive inspection pre-TAR to monitor H blistering
Inspection history:
• 2012: Tri-Plex AUT, identified H blistering
• 2018: Tri-Plex AUT, no growth in blistering
• 2021: Tri-Plex AUT, no growth in blistering
Solution
2022: TriLat and PAUT weld inspection deployed robotically
TriLat with TFM and PCI Imaging
Result
Significant HIC and weld-adjacent SOHIC found
2023: Removed from service and replaced
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Amine Recycle Gas Scrubber
Tri-Plex AUT
Tri-Lateral
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Amine Recycle Gas Scrubber
TriLat 0° PA
TriLat 0° TFM
TriLat 0° PCI
Tri-Lateral
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Amine Recycle Gas Scrubber
TriLat 0° PA
TriLat 0° TFM
TriLat 0° PCI
Tri-Lateral
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
TriLat Data
TFM 0° (L-L)
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
TriLat Data
PCI 0° (L-L)
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.
Questions
Brandon Reitz
NDT TECHNOLOGY MANAGER
brandon.reitz@geckorobotics.com
Copyright © 2023. Gecko Robotics, Inc. All Rights Reserved.
Contains confidential information. Do not distribute.