Post on 27-Jul-2020
transcript
www.thermalwave.com
Dr. Steven Shepard
President
Thermal Wave Imaging. Inc.
Mr. Paul Kulowitch,
NDI Engineer Team Leader
Naval Air Warfare Center,
Patuxent River
Automated, Rapid Non-Destructive Inspection
(NDI) of Large Scale Composite Structures
www.thermalwave.com
Early diagnosis and repair of
structural problems based on
Nondestructive Inspection (NDI)
is essential for optimum platform
performance and readiness
NAVAIR NDI
www.thermalwave.com
Current Problem
• Traditional methods used in metals ineffective (visual, coin tap)
• Point inspection methods time consuming for large structures
• Special coatings and structures may complicate inspection
• Disassembly for inspection undesirable
• Composite inspections
– Impact damage
– Water entrapment
– Delamination
– Disbonding of joined structures
– Heat damage
The increasing use of composites in Navy aircraft presents
numerous challenges to current NDI capability
www.thermalwave.com
Fleet Requirements
• Decrease inspection time during scheduled maintenance
of large aircraft structures
• Aid inspector in discriminating between flaw indications
and normal variations
• Provide quantitative metric for operator decision
• Simplify operator training
www.thermalwave.com
Current Approaches
Method Advantages Issues
Coin tap Low-cost Large, near surface features only
Ultrasound Excellent penetration
Well-established standards and
procedures
Point inspection or scanning required
Requires contact, couplant
Radiography Area inspection
Excellent crack detection
Insensitive to many voids or
delaminations
Thermography Area inspection
Provides information about flaw type
Operates in close proximity to aircraft
Limited depth range
Shearography Area inspection Limited depth range
Issues at edges and corners
www.thermalwave.com
• Aggressive support of new and emerging NDI technologies through SBIR /
STTR programs
– Portable imaging ultrasound (Imperium)
– MWM Array Eddy Current (Jentek Sensors)
– Portable and quantitative thermography (Thermal Wave Imaging)
• High success rate of commercialization and transition to fleet
Advanced NDI Development
www.thermalwave.com
• Long history of support and development of thermography for NDI
– Flash thermography
– Modeling
– Vibrothermography
– Thermographic Signal Reconstruction (TWI)
– Portable systems
NAVAIR and Thermography
www.thermalwave.com
• Non-contact
• Single side access (no disassembly required)
• Flat or curved surfaces (no critical alignment required)
• Area inspection
• Image result
Thermography Advantages
www.thermalwave.com
• High end cameras required
– expensive, large, delicate
• Limited operation in close proximity to aircraft
• Advanced signal processing required
• Training
• Time consuming for large area
Deployment Issues
An operator in close
proximity to the aircraft
inspects a small area with
flash thermography.
www.thermalwave.com
NAVAIR Phase II SBIR
• Large area thermography at a large working distance from aircraft
• Apply advanced signal processing to non-standard signal
• Simplify / automate inspection and interpretation
Automated, Rapid Non-Destructive Inspection
(NDI) of Large Scale Composite Structures N092-097 Cherry Point
www.thermalwave.com
Remote NDI: A New Paradigm
• NDI of large structures typically requires a fixed installation to scan a
point inspection device that is in close proximity to the surface over
a large area.
• We have developed a solution that is capable of inspecting a large
area quickly, and a distance from the target, while offering sensitivity
comparable to existing technologies.
Conventional
scanning TWI Large Standoff
< 50 ft
www.thermalwave.com www.thermalwave.com
LASLAT Projection NDI
• Rapid inspection of large structures
– Noncontact
– Results archived as single image
– Quantitative flaw analysis
• Fixed or portable implementation
– No fixed gantry or infrastructure required
– Mount on tripod, cart, truck, boat etc.
– Truck or boat mounted
• Performance comparable to close proximity methods
– Detection of subsurface voids, delamination, moisture, corrosion
• Inspection of inaccessible or hazardous components
Large Standoff / Large Area
Thermography (LASLAT)
< 50 ft
LASLAT uses TWI Thermographic Signal
Reconstruction to provide laboratory quality
results in a far-field system
www.thermalwave.com
LASLAT
An operator in close
proximity to the aircraft
inspects a small area with
flash thermography.
IR camera
heat
projector
Baseline Approach
NDI system positioned far from
aircraft to inspect large area.
LASLAT Projection Thermography
www.thermalwave.com
Thermographic Signal
Reconstruction (2000)
U.S. Patent 6,516,084
reconstructed
raw
0.000 5.781
1.182
6.208
2.363
6.635
3.545
7.063
4.726
7.490
5.908
7.918
ln (frame num)
ln (
T –
T0)
Fit raw log-log data with a
smooth function and use the
replica for analysis and
further processing.
• Excellent fitting
• Conversion < 5 sec
• Temporal noise reduction
• Store coefficients of fit
equation only
• Smaller file size
• Faster processing
www.thermalwave.com
TSR Derivatives
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
0 1 2 3 4 5
ln (T
)
ln (t)
0.150 sec
TSR
2nd derivative
TSR
TSR
1st derivative
0.150 sec
-0.60
-0.50
-0.40
-0.30
-0.20
-0.10
0.00
0 1 2 3 4 5
d[ln
(T)]
/ d
[ln
(t)]
ln (t)
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
0 1 2 3 4 5
d^2
[ln
(T)]
/ d
[ln
(t)]
^2
ln (t)
www.thermalwave.com www.thermalwave.com
Thermographic Signal
Reconstruction
Raw thermography data TSR processed
TTU
X-ray Conventional Flash Thermography
TSR
Disbond
www.thermalwave.com
Extended Pulse Heating
heating period
t0
Early behavior of signals of interest
may be masked during heating period.
Heating and cooling occur simultaneously during extended heating
www.thermalwave.com
Performance
Features Advantages Benefits
Large standoff distance Access to large structures
without fixed installation
Reduced cost and
adaptation to multiple
inspections
Operation in fuel vapor
areas
Large inspection area No fixed scanning apparatus
required
Reduced installation
cost
Reduced inspection time
TSR signal processing Improved detection
sensitivity
Meet/exceed existing
requirements
Verify/assist operator in
flaw detection
www.thermalwave.com
TSR Processing
Proprietary Thermographic Signal Reconstruction processing extracts subsurface features that are undetectable in raw data.
TSR
Unprocessed
Time sequence of carbon fiber honeycomb panel acquired with LASLAT system at 50’.
Skin-to-core disbond
Inter-ply delamination
skin Al core
www.thermalwave.com
System Performance
• Operating range 5-50 ft from inspection surface
• Instantaneous coverage area: ~2 ft2
• Total coverage area: ~ 400 ft2
Comparison of LASLAT at 45’ and close proximity commercial
thermography system on a composite panel with hidden flaws.
45’ projection Close proximity flash
Comparison of projection system at 45’ and close proximity commercial
flash thermography system on a composite panel with hidden flaws.
www.thermalwave.com
Large Area Inspection
• Instantaneous coverage area: ~4 ft2
• Total coverage area: ~ 400 ft2
• 81 shots, 3-4 hr inspection time
• Software controlled: creates full area image and flaw detection
System area coverage at 50 ft. stand-off
23’
18’
2.5’
2’
System software automatically combines far-
field data into a single image.
6’
2’
www.thermalwave.com
Current State of Development
• Current state: TRL 3-4
– Working prototype in lab environment
• Field demo scheduled Q1 2013
– Target state: TRL 5
Imaging
and
excitation
Signal
processing
Application
specific
hardware
Software
www.thermalwave.com
Questions?