NONDESTRUCTIVE MONITORING OF
OFFSHORE WIND TURBINE BLADES
Offshore wind turbine blades are large composite structures that operate in harsh
marine environments under highly cyclic loading. Their integrity drives safety, avail-
ability, and lifetime energy production. Few recent US patents have focused on
the development of nondestructive inspection and monitoring solutions that allow
inspection inside the blade, capture high-resolution surface conditions on rotating
blades, and further track deflection in real time. The three patents summarized
below illustrate complementary directions in this area.
These patents demonstrate how nondestructive ultrasonic scanning, synchronized
optical inspection of rotating blades, and continuous deflection monitoring can be
integrated into comprehensive inspection and structural health monitoring strate-
gies for offshore wind. Such multimodal methods facilitate risk-based maintenance,
extend asset life, and lower costs across large offshore wind fleets.
US20250305994A1 ULTRASONIC
INSPECTION MACHINE
FOR PERFORMING
NONDESTRUCTIVE
ULTRASONIC
INSPECTIONS ON WIND
TURBINE BLADES
(Ivan Castro Casas, Iratxe Aizpurua
Maestre, and Hector Gutierrez)
This patent details a self-contained ultra-
sonic inspection machine mounted on an
automatically guided vehicle. A six-axis
robotic handling device carries a robot
head equipped with a scanning head, an
array of ultrasonic transducers, a blade-
marking device, a machine vision camera,
illumination, and a distance sensor. The
system marks “working windows” on the
blade surface, locates them with vision,
and then scans each window using
programmed horizontal and vertical
passes. At the same time, a water-film
couplant maintains acoustic coupling.
The result is high-coverage, repeatable
ultrasonic testing (UT) inspection of the
full blade surface with minimal manual
intervention, suitable for both onshore
and offshore blades in manufacturing or
maintenance settings.
US12073547B1 SYSTEM AND A METHOD
FOR INSPECTION
OF ROTATING WIND
TURBINE BLADE
(Janis Putrams)
This invention allows high-resolution
visual inspection of blades while they
remain in rotation, using a camera
mounted on a controllable rotating
mechanism that works together with
one or more laser distance sensors or
dynamic vision sensors and a computer
system to capture high-resolution images
of selected spots on the leading edge,
trailing edge, and suction and pressure
sides without stopping the turbine. The
computer continuously estimates blade
tip speed and phase, synchronizing the
camera motion and shutter timing with
the targeted blade area. In this way, the
system reduces downtime compared to
rope-access or parked-blade inspections
and supports frequent inspections for
erosion, cracks, and lightning damage in
offshore wind farms.
US11639712B2 SYSTEM AND METHOD
FOR MONITORING
BLADE DEFLECTION
OF WIND TURBINES
(Vincent David, Daniel Cantin, Robert
Guillemette, and Jonathan Cloutier)
This patent describes a system that
measures the deflection of turbine
blades toward or away from the tower
during operation. The system detects
abnormal loading or excessive deflection
using a position-detection apparatus
mounted on the turbine. Each apparatus
includes multiple detection components,
each monitoring a field of detection
associated with a blade segment or
blade tip. A deflection controller uses
presence/absence or distance data from
these components to infer the distance
between each blade segment and the
tower, providing a real-time estimate of
blade deflection and minimum clearance.
When abnormal or excessive loading is
detected, the system triggers alarms and
informs lifetime and fatigue assessments
for offshore turbines.
PATENTS EDITOR
Samir Mustapha, PhD: American
University of Beirut, Beirut, Lebanon
sm154@aub.edu.lb
SCANNER
|
PATENTSROUNDUP
Patents Roundup provides a review of recent
patents of interest to the NDT community. If you’ve
been granted a patent and would like to see it
featured in an upcoming issue, please email Patents
Editor Samir Mustapha at sm154@aub.edu.lb.
ASNT REWIND
Join us online on 18 March for a recap of
the top presentations and most impactful
insights from ASNT 2025! REWIND
sessions earn contact hours and can be
converted into recertification points for
ASNT NDT Level III. Registration informa-
tion coming soon.
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SOCIETYNOTES
18
M AT E R I A L S E V A L U AT I O N • J A N U A R Y 2 0 2 6

J3277/1_202501: LIQUID LEAK TIGHTNESS
STANDARDS FOR PROPULSION BATTERY
PACKS RECOMMENDED PRACTICE
The rapid rise of electrified propulsion
systems has intensified the demand for
safe, reliable, and watertight battery packs.
Responding to this need, the Society of
Automotive Engineers (SAE) has issued
J3277/1_202501, a new recommended
practice that establishes nondestructive
in-line production test methods for eval-
uating liquid leak tightness in propulsion
battery packs. The standard addresses
a critical gap by defining robust qualifi-
cation, verification, and validation proce-
dures that meet industrial expectations for
safety, durability, and energy security.
A STANDARD FOR
MODERN EV SAFETY
Water ingress is one of the most signifi-
cant threats to the performance of elec-
tric vehicles (EVs). Moisture intrusion can
lead to electrical shorts, thermal runaway,
corrosion, and latent failures that jeopar-
dize both safety and product warranty.
The new SAE J3277/1 standard formal-
izes best practices for nondestructive
leak testing at scale, delivering a clear
framework for manufacturers of automo-
tive, marine, aerospace, and stationary
energy storage systems.
The practice is built around a
production-friendly philosophy, enabling
high-speed, repeatable testing during
assembly without exposing packs to liquid
or causing damage. It introduces perfor-
mance evaluation tools for qualifying test
equipment and methods, ensuring that
leak detection remains consistent, trace-
able, and quantifiable over time.
NDT AT THE CORE:
THE EQUIVALENT
CHANNEL METHOD
A significant contribution of this standard
is its promotion of nondestructive testing
(NDT) rather than destructive evaluation.
Among the recommended approaches,
the equivalent channel (EC) method
stands out as an efficient solution for
detecting leakage paths. Instead of
flooding the pack with fluids, the method
measures pressure decay or flow char-
acteristics through engineered channels.
These channels mimic actual leak paths,
allowing the system to determine sensi-
tivity and reliably detect defects.
By using controlled channels, manufac-
turers can:
Ñ Evaluate test system responsiveness
Ñ Verify the minimum detectable leak
rate
Ñ Benchmark equipment performance
and calibration stability
Ñ Avoid handling of hazardous liquids
or thermal cycling
This system enables high-volume
production verification without inter-
rupting manufacturing flow.
STRENGTHENING
RELIABILITY THROUGH
NONDESTRUCTIVE
TECHNIQUES
Leak tightness is directly tied to safety,
warranty cost, and regulatory compli-
ance. SAE J3277/1 provides a struc-
tured methodology to examine battery
enclosures, seals, welds, gaskets, coolant
passageways, and venting systems. NDT
allows inspection teams to locate failure
points early, preventing moisture intru-
sion during service.
Applications extend across:
Ñ Passenger EVs and commercial
transport
Ñ Electric buses and fleet vehicles
Ñ Marine propulsion battery
systems
Ñ Off-road and industrial
electrification
Ñ Energy storage in harsh
environments
In each case, nondestructive leak
testing supports long-term asset integrity,
enabling compliance with OEM, fleet,
and regulatory requirements.
IMPACT ON QUALITY
AND RISK REDUCTION
The publication of SAE J3277/1_202501
helps unify industry practice by defining
consistent acceptance criteria and cali-
bration requirements for leak detection
systems. Manufacturers now have a
shared metric for evaluating seal quality,
reducing false positives, and minimizing
field failures. Standardization improves
transparency and accelerates supplier
qualification, while nondestructive
approaches cut waste, cycle time, and
rework.
CONCLUSION
SAE J3277/1_202501 marks an important
milestone for battery safety. By enabling
reliable, repeatable, and nondestruc-
tive assessment of liquid leak tightness,
the standard helps ensure that propul-
sion battery packs remain sealed and
protected throughout their service life.
With the electrification trend driving new
applications in transportation and energy
systems, the adoption of this recom-
mended practice will support safer vehi-
cles, stronger supply chains, and more
resilient designs, delivering confidence to
manufacturers and users alike.
STANDARDS EDITOR
Hossein Taheri, PhD: Georgia Southern
University, Statesboro, GA
htaheri@georgiasouthern.edu
STANDARDSUPDATE
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SCANNER
J A N U A R Y 2 0 2 6 • M AT E R I A L S E V A L U AT I O N 19