Lock-in Thermography

A World Class Supplier of IR
Imaging Systems
Non Destructive Testing
by Heat wave detection
Presented by Pierre BREMOND
CEDIP
19 Bld Georges Bidault
F 77183 Croissy Beaubourg
Email: pierre.bremond@cedip-infrared.com
Web: www.cedip-infrared.com
A market leader in innovative IR imaging solutions

Summary
A World Class Supplier of IR
Imaging Systems
• Introduction
• Active thermography
• Pulse Thermography
• Long Pulse Thermography
• Lock-in Thermography
• Heat wave system
• Applications of Heat Wave detection usinf Lockin Thermography
Aluminum Epoxy
CRFP
Carbon Fiber
Polymers
Fatigue limit measurement
• Conclusions
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Introduction
A World Class Supplier of IR
Imaging Systems
Thermal methods in Non Destructive Testing consist of using Infrared camera to detect sub
surface defect thank to Heat Wave.
Thermal Non Destructive Testing allows evaluating Quality of structures during design (R&D),
production (Quality Control) and after use (Maintenance).
Major applications concern :
R & D, characterization of material and improvement of process
QC, Go / No Go during process. Process of welding, gluing, heat traitment, moulding
Maintenance, default detection, impact, crack.
Accurate Thermal Non Destructive methods use:
Active Thermography – Heat wave is sent through material by external or internal
sources (lamps, US, microwaves, hot wind, etc).Internal defects change the thermal
response on surface of structures. Heat waves allow measuring depth, size and thickness
of internal flaws.
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Techniques of Active Thermography
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Imaging Systems
• Pulse Thermography (PT)
– Former method based on a very short time heating 20KJ with Xenon lamps
– Problems:
– Requires uniform heating and processing based on temperature / time analysis
– Recording then processing (time consuming)
– High temperature of controlled surface & limited to IR lamps
– Application: Maintenance
• Long Pulse Thermography (LPT)
– Long heating then Fourier Transform analysis
– Problems:
– Energy spread over every frequency
– Recording then processing (time consuming), S/N limitation
– Limited to IR lamps
– Advantage
– Phase measurement independent of temperature uniformity
– Application: R&D
• Lock-in Thermography (LIT)
– Steady state heating, S/N improvement by frame accumulation
– Advantage:
– Energy concentrated on one single frequency, real time processing
– Phase measurement independent of temperature and uniformity of heating
– Large surface, not sensitive to surrounding by Lock-in
– Ultra Sound, microwave, optical heating can be used
– Note that depth penetration of phase is 2 times greater than amplitude
– Applications: On line quality control, crack detection, R&D and Maintenance.
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Example (steel specimen)
A World Class Supplier of IR
Imaging Systems
Phase measurement versus depth of default for different modulation frequencies
Phase (deg)
35
30
25
20
15
10
5
0.8 Hz
0.7 Hz
0.6 Hz
0.5 Hz
0.4 Hz
0.3 Hz
0.2 Hz
0.1 Hz
0.09 Hz
0. 08 Hz
0
0 0.5 1 1.5 2 2.5
-5
-10
-15
De pth (mm )
A market leader in innovative IR imaging solutions

A World Class Supplier of IR
Imaging Systems
Applications of Lock in
Thermography
• With optical excitation:
– Coatings (thickness of paint on polymer, automotive industry) - high
frequency ~ 5Hz (laser) - accuracy +/-5µm.
– Veneered wood (Lose of adhesion, wood industry)
– Laminates (local disbonding, delamination, impact, integrity of structure)
– Ceramics coating on metals (lose of adhesion)
– Corrosion (aluminium)
– Plates screws fastened (torque)
• With internal excitation (US, mechanical loading, micro- wave)
– Cracks
– Disbonding
– Water
• With internal excitation (US, mechanical loading, micro- wave)
– Cracks
– Disbonding
– Water
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A World Class Supplier of IR
Imaging Systems
Size of order
• Detectable default:
– diameter > depth
• Depth versus material:
– Glass-epoxy ~ 16 mm
– Carbon-epoxy ~ 8 mm
– Steel ~ 5 mm
– Aluminium ~ 4 mm
Composite, image de phase
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Depth of penetration versus
modulation frequency
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Imaging Systems
La profondeur du défaut est
liée à la fréquence
Plus la fréquence est basse
plus le défaut détecté est
profond.
Cette fréquence dépend du
matériau
1Hz to 0.001Hz.
Frequency= 0.100 0.090 0.080 0.070 Hz
A market leader in innovative IR imaging solutions

A World Class Supplier of IR
Imaging Systems
Sketch of setup
JADE MWIR,
Lock in Module
PC + ALTAIR-LI
Halogen Lamps
1KW, 220V
1 cable / lamp
Amplifier for 6 lamps
Function generator
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JADE Cameras
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Imaging Systems
• Absolute measurement of temperature
• Format: 320 x 256 MWIR (3.7 à 5.2µm)
•
• Thermal drift controlled
• Accuracy +/-2°C, +/-2%
• Stirling Cooler
• NETD 20 mK @ 25°C,
• Trigger (300 ns)
• Integration time: 3 µs à 1 ms
• Frame rate & windowing : 200 i/s à 9000 i/s
JADE MWIR
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Workstation
ALTAIR-LI
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Imaging Systems
JADE camera (MWIR ou LWIR)
Lenses: 25mm (FOV 40cm @ 1m) ou 12mm (FOV 80cm @ 1m)
Lockin Module (real time processing)
PC including software ALTAIR-LI & ALTAIR
Heating system:
Lamps (1KW) 6 maximum .
Function generator (sinus or pulse long)
Amplifier (32A).
Frequency: 8 Hz (filament lamps) à 5mHz (measure par Altair-LI)
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A World Class Supplier of IR
Imaging Systems
ALTAIR-LI station
PC with Dockin station
Module Lock-in
Function generator
Amplifier
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IR lamps
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Imaging Systems
JADE MW
Halogen lamps
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ALTAIR-LI software
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Imaging Systems
Click in
image
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A World Class Supplier of IR
Imaging Systems
Phase calculation by ALTAIR-LI
Frequency: 80mHz
Calculation time: 5 periods
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A World Class Supplier of IR
Imaging Systems
Reporting-ALTAIR
Image de phase à 80mHz
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A World Class Supplier of IR
Imaging Systems
Reporting-ALTAIR
Image de phase à 80mHz
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A World Class Supplier of IR
Imaging Systems
Reporting-ALTAIR
A market leader in innovative IR imaging solutions

A World Class Supplier of IR
Imaging Systems
Aluminum- Epoxy structure
Thermal image
Map of defect
Epoxy Aluminum Honeycomb structure
Frame rate : 50Hz Full-frame
Frame accumulation: 1500 frames
Processing Time :
10 seconds
Lock in Frequency :
0.1 Hz
Double click on the B&W image to see the film.
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Honeycomb - Aluminum Epoxy
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Imaging Systems
Lock in Frequency :
Number of periods:
Time processing:
0.1 Hz
1 period
10 seconds
Thermal image
Amplitude image
Phase image Map of defect
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CRFP
A World Class Supplier of IR
Imaging Systems
Lock in Frequency :
Number of periods:
Time processing:
0.2 and 0.1 Hz
3 periods
20 seconds
Amplitude image
Phase image face 1 frequency : 0.2Hz
Phase image face 2 frequency : 0.09Hz
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Carbon fiber specimen
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Imaging Systems
Lock in Frequency :
Number of images:
Time processing:
0.2 Hz
500 images
20 seconds
Thermal image
Amplitude image
Phase image face 2 frequency : 0.09Hz
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CRFP + aluminum honeycomb
A World Class Supplier of IR
Imaging Systems
Lock in Frequency :
Number of periods:
Time processing:
0.08 Hz
5 periods
30 seconds
Thermal image
Amplitude image
Phase image Map of defect
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CRFP + aluminum honeycomb
A World Class Supplier of IR
Imaging Systems
Time processing:
20 seconds
Phase image at frequency : 0.5Hz
Phase image at frequency : 0.2Hz
Phase image at frequency : 0.08Hz
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A World Class Supplier of IR
Imaging Systems
Non Destructive Testing -- Data acquisition
Thermal image
Aluminium + honeycomb in aluminum +aluminium with black paint
Frame rate : 150Hz Full-frame
Frame accumulation: 3000 frames
Processing Time :
20 seconds
Lock in Frequencies : 0.2Hz, 0.1 Hz, 0.05Hz, 0.01Hz
Double click on the image to see the film.
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A World Class Supplier of IR
Imaging Systems
Alum. honeycomb specimen -- Results
Phase image at frequency : 0.5Hz
Phase image at frequency : 0.2Hz
Phase image at frequency : 0.1Hz
Phase image at frequency : 0.05Hz
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Problem:
Quality control during manufacturing
of Carbon Epoxy composite element
for large aircraft.
A World Class Supplier of IR
Imaging Systems
Solution:
Altair-Li with modulated heating using an
infrared lamp at 0.267 Hz.
Amplitude image
Phase image shows different depth
calibrated defect.
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A World Class Supplier of IR
Imaging Systems
Problem:
The industrial environment is thermally
polluted or the emissivity of the
component is not homogeneous.
Solution:
Altair- LI uses Lock-in Thermography to extract
thermal information from the noise and measures
phase angle.
The phase angle is independent
of the local variation of
illumination or of surface
emissivity.
Thermal Image
Amplitude Image
Phase Image
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A World Class Supplier of IR
Imaging Systems
Problem:
Measure the defect depth in ceramics.
Solution:
Altaïr-LI measures the absolute phase
between excitation and thermal response.
2 1
Amplitude image and profiles.
Phase image and profiles.
Absolute Phase is
a function of
defect depth.
The phase image shows clearly that the depth of the calibrated defects is twice the depth in
sample number 2 as in sample number 1. There is no defect in the other samples.
A market leader in innovative IR imaging solutions

A World Class Supplier of IR
Imaging Systems
Problem:
Detection of internal corrosion on
aircraft structure.
Solution:
Altair-Li with modulated heating using an
infrared lamp at 0.240 Hz.
Amplitude image
Phase image. The resolution of the
thickness is better with phase
measurement.
A market leader in innovative IR imaging solutions

References
France
A World Class Supplier of IR
Imaging Systems
AIRCRAFT INDUSTRY
APPLICATIONS
DASSAULT* Argenteuil NDT on aircraft component, Lock in and Pulse Thermography
EADS* Bordeaux, Les Mureaux, NDT on satellite and Aircraft component (R&D
Suresnes
and Production control)
ONERA* Chatillon R&D on Lock in Thermography and Pulse Thermography (IR lamps
&
microwave).
SNECMA* Bordeaux NDT (Production control on high temperature material)
NUCLEAR INDUSTRY
CEA Cadarache NDT on high temperature material
FRAMATOME* Chalons
NDT by Flying point method. Crack detection in Nuclear plants
Patterned CEDIP exclusive vendor.
AUTOMOBILE & RAILWAY INSDUSTRY
CITROEN Velizy Stress Analysis
PSA Belfort, Stress Analysis and NDT on thermal barrier and high temperature
Poissy
coating.
RENAULT Boulogne, Lardy, Guyancourt Stress Analysis
SNCF* Vitry NDT on structural composite and Stress Analysis
UNIVERSITY RESEARCH CENTERS
X Palaiseau R&D in Fatigue and damage assessment
ENIT Tarbes Stress Analysis
ENSAM Bordeaux R&D in NDT
ENSAM Châlons en Champagne R&D in Stress Analysis and Fatigue
ENSEM Nancy R&D in NDT Pulse method and Thermo mechanics
ENSMA Poitiers R&D in Thermo mechanics
ESIA Annecy R&D in Thermo mechanics
ESPC Paris R&D. Lock in Thermography. Tribology.
EUDIL Lille R&D in Stress Analysis
ICAM Nantes R&D in NDT and Material Evaluation
IUT Lorient R&D in NDT and Material Evaluation
IUT Ville d’avray R&D NDT
* Non Destructive Testing
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References
France
A World Class Supplier of IR
Imaging Systems
UNIVERSITY RESEARCH CENTERS
LMA Besançon R&D thermomecanics. Lock in Thermography on Polymers.
SUE* Reims R&D in NDT. Pulse, Lock in Thermography
LMGC Montpellier R&D in Thermo mechanics
MATERIAL RESEARCH CENTERS
LCPC Nantes R&D in Thermo mechanics
LNE Trappes French Standard Centre
DEFENCE INDUSTRY
APPLICATIONS
DGA / CEG Gramat Electromagnetic Field measurement. Lock in Thermography on
microwave
* Non Destructive Testing
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International
References
A World Class Supplier of IR
Imaging Systems
AIRCRAFT INDUSTRY
APPLICATIONS
Aeronautica Militare* (Italy) NDT on aircraft Maintenance
AGUSTA* (Italy) Stress analysis in ground Test centre
AIRBUS Industries* (U. K.) R&D NDT for Carbon-Carbon component
GOODRICH (USA) On line control. NDT on aluminum
MTU* (Germany) Turbine blade control. On line production
National Aerospace Laboratory(Japan) Stress and Fatigue analysis
Eurocopter* (Germany) R&D on NDT. Metal and composite. Stress analysis.
ELECTRO-OPTICS, LASERS INDUSTRY
Indian Institute of Techn. (India) R&D NDT. Lock in Thermography
AUTOMOBILE & RAILWAY INSDUSTRY
BMW (Germany) On line control NDT. Lock in Thermography on leather (Ir lamps).
Lock in Thermography (crack detection with Ultra sound)
CACIA SA (Portugal) Fatigue testing
DAIMLER CHRYSLER (USA) Stress Analysis
DAIHATSU (Japan) Stress Analysis
DENSO (Japan) Stress Analysis
KAYABA KOYO (Japan) Stress Analysis
KOBE STEEL ‘Japan) NDT, Stress Analysis
MITSUBISHI (Japan) Stress Analysis
NTN (Japan) Stress Analysis
NSK Warner (Japan) Stress Analysis
NISSAN (Japan) Stress Analysis
ROVER (U. K.) Stress Analysis
SUZUKI (Japan) Stress Analysis
TOYOTA (Japan) Stress Analysis
YAMAHA (Japan) Stress Analysis
UNIVERSITY RESEARCH CENTERS
Deakin University (Australia) R&D molding process
Monash University (Australia) R&D NDT Aircraft industry
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International
UNIVERSITY RESEARCH CENTERS
References
A World Class Supplier of IR
Imaging Systems
Joaennen Institute (Austria) R&D NDT
University of Aachen (Germany) R&D NDT on bonding material
University of Bath (U.K.) R&D on aircraft component
University of Warwick (UK) R&D Stress measurement on Automotive component
University of Stuttgart (Germany) R&D on Lock in Thermography. Ultrasound technique.
ELECTRONICS
IRDE (India) R&D on High temperature material
GLASS, STEEL INDUSTRY, ENERGY
CESI* (Italy) Lock in Thermography. Thickness measurement of thermal coating.
CORUS (The Netl.) Fatigue analysis
KOBE STEEL (Japan) Stress Analysis
PLANSEE* (Austria) NDT on High temperature material
* Non Destructive Testing
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