Boeing 787 Composite Structures - BRIDGE ... by Boeing Smart Composite System Laboratory The...
Transcript of Boeing 787 Composite Structures - BRIDGE ... by Boeing Smart Composite System Laboratory The...
1
Smart Composite System Laboratory The University of TokyoSmart Composite System Laboratory The University of Tokyo
Structural Health Structural Health Monitoring of Aerospace Monitoring of Aerospace
Composite StructuresComposite Structures
Presentation at APSSAugust 2, 2010
Kashiwa Campus, the University of Tokyo
Nobuo TakedaNobuo TakedaThe University of TokyoThe University of Tokyo
Dept. Advanced EnergyGraduate School of Frontier Sciences
andDept. Aeronautics and Astronautics
School of Engineering
Smart Composite System Laboratory The University of Tokyo
Boeing 787
Reusable Launch Vehicleof JAXA/ISAS
Airbus A380
Structural Health Monitoring (SHM) is a key technology for safety assurance and maintenance cost reduction
Increasing Use of Advanced Increasing Use of Advanced Composites in Aerospace StructuresComposites in Aerospace Structures
Courtesy by Airbus
Courtesy by Boeing
to reduce weight for energy saving
Smart Composite System Laboratory The University of Tokyo
Composites50%
Titanium15%
Other5%Steel
10%
Aluminum20%
CFRPCFRPサンドイッチ
GFRPアルミ合金
鋼・チタン エンジンパイロン
複合材
アルミ合金
チタン合金
鋼材その他
Composites50%
Titanium15%
Other5%Steel
10%
Aluminum20%
CFRPCFRPサンドイッチ
GFRPアルミ合金
鋼・チタン エンジンパイロン
複合材
アルミ合金
チタン合金
鋼材その他
Materials Used in Boeing 787 AircraftMaterials Used in Boeing 787 Aircraft
CFRP50%
Al Alloys20%
Ti Alloys15%
Steel10%
Others5%
CFRPCFRP SandwichGFRPAl AlloysSteel & Ti Alloys, Engine Pyron Courtesy by Boeing
Smart Composite System Laboratory The University of Tokyo
Feb. 2005, Newton
Composite Materials and Structures are most important in Japanese aerospace industries
Smart Sensing and Structural Health Monitoring are key technologies for safe operation and efficient
maintenance for future aerospace structures
Smart Composite System Laboratory The University of Tokyo
OutlineOutline(1)(1) Structural Health Monitoring Group,Structural Health Monitoring Group, NEDO Smart NEDO Smart
Material/Structure System Program (FY1998Material/Structure System Program (FY1998--2002)2002)
(2)(2) Structural Integrity Diagnosis and Evaluation of Structural Integrity Diagnosis and Evaluation of Advanced Composite Structures (ACSAdvanced Composite Structures (ACS--SIDE) SIDE) Project,Project, METIMETI Advanced Material & ProcessingAdvanced Material & Processingforfor NextNext--Generation Aircraft Structure ProgramGeneration Aircraft Structure Program(FY2003(FY2003--2007)2007)
(3) Integrated High(3) Integrated High--Resolution Distributed Strain Resolution Distributed Strain Monitoring with Embedded Optical Fibers in Monitoring with Embedded Optical Fibers in Composite Composite StStruructuresctures (FY2007(FY2007--))
Smart Composite System Laboratory The University of Tokyo
Health MonitoringUniv. Tokyo10 Companies
Active/Adaptive Structures
Nagoya Univ.4 Companies
& Tokyo MMU
Smart ManufacturingOsaka City Univ.
2 Companies
Actuator Materials& Devices
Tohoku Univ.4 Companies &
Univ. of Washington
DemonstratorProgram
4 Companies
National Institute of Advanced Industrial Science and TechnologySmart Structure Research Center
METI(Ministry of Economy, Trade and Industry)
NEDO(New Energy and industrial Technology Development organization)
RIMCOF(R&D Institute of Metals & Composites for Future Industries)
5 Year ProgramFrom April 1998To March 2003
Approximately5 Million US
Dollars per year
NEDO Smart Material/Structure System ProgramNEDO Smart Material/Structure System Program
2
Smart Composite System Laboratory The University of Tokyo
Typical Damages in Composite LaminatesTypical Damages in Composite Laminates
Small-diameter FBG sensors were developed for detection of transverse cracks or the delamination in CFRP laminates.
Transverse Cracks
Delaminations
Typical Thickness of CFRP PrepregLayers: 125 μm
Diameter of Carbon Fiber: 5-8 μm
Smart Composite System Laboratory The University of Tokyo
Ref
ract
ive
Inde
x
10mm0.53μm
Polyimide CoatingCladding
Core
6.5μm40μm
52μm
SmallSmall--diameter Fiber Bragg Grating Sensordiameter Fiber Bragg Grating Sensor
FBGCore Cladding
Smart Composite System Laboratory The University of Tokyo
Cladding PolyimideCoating
50μm
0o Ply
90o Ply
Uncoatednormal FBG sensor
Polyimide-coatedsmall-diameter FBG sensor
Cladding: φ 125μm Cladding: φ 40μmPolyimide Coating: φ 52μm
CFRP Laminates with Embedded FBG SensorsCFRP Laminates with Embedded FBG Sensors
Smart Composite System Laboratory The University of Tokyo
Response of FBG Response of FBG Sensor to StrainSensor to Strain
λ0 λ1
IR
Incident Light
TransmittedLight
λ1 d=0.5μm
Reflection spectrum is narrowband.Strain determined from wavelength shift.
Incident Light Transmitted
Lightλ1λ2
λ3
λ0 λ1
IR
λ2 λ3
Reflection spectrum becomes broadband,which can be used for damage detection.
Uniform strain Non-uniform strain
Small-Diameter Optical Fiber
FBG0o Ply
0o Ply90o Ply
Transverse CracksTensile Load
Small-diameter FBG Sensors can be embedded close to transverse cracks without deteriorating the laminate.
λ1=C1d=C2ε
Smart Composite System Laboratory The University of Tokyo
Detection of Transverse CracksDetection of Transverse Cracks
Small-Diameter Optical Fiber
FBG Sensor
CFRP: T800H/3631Laminate configuration: quasi-isotropic [45/0/-45/90]s
GFRP TabA
A
Cross section at A-A50μm
Cladding
Polyimide Coating
90o Ply
-45o Ply
Embedded FBG sensor in –45o ply for detection of 90o transverse cracks
Smart Composite System Laboratory The University of Tokyo
Reflection Spectra at Various Tensile Strain LevelsReflection Spectra at Various Tensile Strain Levels
1551 1555 1553 1557 1553 1559 1553 1559
0.2
0.15
0.1
0.05
0
Ref
lect
ivity
Wavelength (nm)
(A) ε = 0.00%, ρ = 0.0cm-1 (D) ε = 1.10%, ρ = 7.1cm-1
(B) ε = 0.49%, ρ = 0.0cm-1 (E) ε = 1.31%, ρ = 12.7cm-1
(C) ε = 0.90%, ρ = 1.4cm-1
(A) (B) (C) (D) (E)
Crack density ρ vs. tensile strain ε. Reflection spectra measured under tensile loading.
0
5
10
15
0 0.5 1 1.5
Cra
ck D
ensi
ty (
cm-1
)
Strain (%)
(A) (B)(C)
(D)
(E)
Detection of Transverse CracksDetection of Transverse Cracks
Reflection spectrum was sensitively deformed with increase in crack density
3
Smart Composite System Laboratory The University of Tokyo
0
0.2
0.4
0.6
0.8
1
1.2
1548 1550 1552 1554
Nor
mal
ized
Inte
nsity
Wavelength (nm)
Ld = 0mm
No. of Cycles = 0
1548 1550 1552 1554Wavelength (nm)
Ld = 5.2mm
No. of Cycles = 20 x 103
0
0.2
0.4
0.6
0.8
1
1.2
1548 1550 1552 1554
Nor
mal
ized
Inte
nsity
Wavelength (nm)
Ld = 7.4mm
No. of Cycles = 100 x 103
1548 1550 1552 1554Wavelength (nm)
Ld = 9.0mm
No. of Cycles = 1000 x 103
Detection of FreeDetection of Free--Edge Edge DelaminationDelamination in Composite in Composite Laminates with Embedded SmallLaminates with Embedded Small--Diameter FBG SensorDiameter FBG Sensor
Intensities of two peaks changed with the delamination growthOptical Loss: 0.4 dB
Smart Composite System Laboratory The University of Tokyo
Impact Damage Impact Damage Detection in Composite StructuresDetection in Composite Structures-- Building Block Approach Building Block Approach --
OPTICAL FIBER
STIFFENED PANEL
FY1998-1999
IMPACT
FY2000-2001 FY2001-2002
Specimen
Impact TestingMachine
SMALL-DIAMETER OPTICAL FIBER
SMALL PANEL CURVED STIFFENED PANELCOUPON
Smart Composite System Laboratory The University of Tokyo
0
0.1
0.2
0.3
0.4
0.5
0 100 200 300 400 500
Distance from impact location to sensor position ,mm
Arr
ival
tim
e o
f st
rain
resp
onse
s ,
ms
□ FBG sensor (Stiffener direction) ● Strain gauge (Stiffener direction) ○ Strain gauge (Orthogonal to stiffener)
● Predected impact position× Impact position□ Sensor position
Arrival Time vs. Distance from Impact Point(Impacted at Stiffener Flange)
Predicted Impact Point(Impacted at Stiffener Flange)
Prediction of Impact Point Using Dynamic FBG ResponsePrediction of Impact Point Using Dynamic FBG Response
Smart Composite System Laboratory The University of Tokyo
Impact Damage Detection –Small-Diameter Optical Fiber
Impact Damage Detection – AE
Damage Detection-BOTDR
Damage Detection – Smart Patch
Damage Suppression -SMA
Low Cost RTM/Health Monitoring
Length: 3 mDiameter: 1.5 m
Overview of Demonstrator
Damage Detection and Suppression DemonstratorDamage Detection and Suppression Demonstrator
Smart Composite System Laboratory The University of Tokyo
OUTSIDE VIEW INSIDE VIEW
EMBEDDED SMALL-DIAMETEROPTICAL FIBER SENSORS
Arrangement of SmallArrangement of Small--Diameter Optical Fibers Diameter Optical Fibers in Upper Panel for Impact Damage Detectionin Upper Panel for Impact Damage Detection
SKIN, STRINGER AND SKIN/STRINGER :20 Optical Fibers including 6 FBG Sensors
Smart Composite System Laboratory The University of Tokyo
Damage Detection and Suppression DemonstratorDamage Detection and Suppression DemonstratorUpper Panel with Embedded Small-Diameter Optical Fiber Sensors
Mid-panel with Embedded FBG SensorsSkin(CFRP)
Loading Fixture(Steel)
Support Fixture(Steel)
Frame(Al alloy)
Trimmable Optical Fiber Connectors
Installed
Mid-panel with Embedded FBG Sensors
4
Smart Composite System Laboratory The University of Tokyo
Impact Damage Detection TestImpact Damage Detection Testin Damage Detection and Suppression Demonstratorin Damage Detection and Suppression Demonstrator
Actuators for Flexural Load
Impact Test Machine
Dead Weight for Gravity Compensation
Impact Response Measuring System
Fixed Reaction Wall
Smart Composite System Laboratory The University of Tokyo
Impact Damage Detection SystemImpact Damage Detection System
VISUALIZATION(by Takeda Lab, Univ. Tokyo)
ANALYSIS/EVALUATION(by Kawasaki Heavy Industries, Ltd.)
Smart Composite System Laboratory The University of Tokyo
OutlineOutline(1)(1) Structural Health Monitoring Group,Structural Health Monitoring Group, NEDO Smart NEDO Smart
Material/Structure System Program (FY1998Material/Structure System Program (FY1998--2002)2002)
(2)(2) Structural Integrity Diagnosis and Evaluation of Structural Integrity Diagnosis and Evaluation of Advanced Composite Structures (Advanced Composite Structures (ACSACS--SIDESIDE) ) Project,Project, METIMETI Advanced Material & ProcessingAdvanced Material & Processingforfor NextNext--Generation Aircraft Structure ProgramGeneration Aircraft Structure Program(FY2003(FY2003--2007)2007)
(3) Integrated High(3) Integrated High--Resolution Distributed Strain Resolution Distributed Strain Monitoring with Embedded Optical Fibers in Monitoring with Embedded Optical Fibers in Composite (FY2007Composite (FY2007--))
Smart Composite System Laboratory The University of Tokyo
ACSACS--SIDE ProjectSIDE ProjectPZTPZT--FBG Hybrid Active Damage Sensing SystemFBG Hybrid Active Damage Sensing System
Fuji Heavy Industries Hitachi CableUniv. TokyoTohoku Univ., AIST
0
5
10
15
20
25
30
35
1548 1549 1550 1551 1552
W ave leng th [nm ]
Tra
nsm
issi
on [
%] Filter 1 Filter 2
+ strain-strain
Lamb wave detection up to 1 MHzLamb wave detection up to 1 MHzAWG (arrayed waveguide grating) filterAWG (arrayed waveguide grating) filter
SAWDSAWDTMTM (Subaru Active Wave Detection) System(Subaru Active Wave Detection) System
SPIE Paper 6932-1
Smart Composite System Laboratory The University of Tokyo
Monitoring of Monitoring of DebondingDebonding at Critical Regions or Hot Spots at Critical Regions or Hot Spots of CFRP Skinof CFRP Skin--Stringer Stringer BondlinesBondlines
PZT FBG Artificial defect
(unit: mm)
15
5
500970
40
16.5 16.5
300
5
10
Skin
Hat-shape stringer
Skin & Stringer: CFRP quasi-isotropic laminates
Smart Composite System Laboratory The University of Tokyo
-40
-20
0
20
40
0 20 40 60 80 100
-40
-20
0
20
40
0 20 40 60 80 100
L = 0mm
L = 5mm
Time (μs)
Vol
tage
(m
V)
-40
-20
0
20
40
0 20 40 60 80 100
L = 7mm
-40
-20
0
20
40
0 20 40 60 80 100
L = 12mm40
0
-40
40
0
-40
40
0
-40
40
0
-40
0 20 40 60 80 100
5000
300
150
L = 0mm
L = 5mm
L = 7mm
L = 12mm
Freq
uenc
y
(kH
z)
0 20 40 60 80 100
5000
300
1505000
300
1505000
300
150
Arrival of the first peak became slower after debonding passed through FBG
Detected Lamb Waves with Growing Detected Lamb Waves with Growing DebondingDebonding(Bonded FBG (A))
Time (μs)
L
(A), (B)
(A) Bonded(B) Embedded
5
Smart Composite System Laboratory The University of Tokyo
: Standard wavelet coefficient ijx ijx : Compared wavelet coefficient
( )∑ −=ij
ijijd
xxN
DI 21
calculated from all the distribution of the wavelet coefficients
Damage Index Damage Index DIDImax
max max
0
2 2
0 0
( ) ( )
( ) ( )
t t
tt t t t
t t
f t g tc
f t g t
=
=
= =
= =
⋅=
∑
∑ ∑
f(t): Standard wavelet coefficient at 300kHzg(t): Compared wavelet coefficient at 300kHz
Correlation Coefficient Correlation Coefficient cc
5000
300
150
L = 0mm
0 20 40 60 80 100 Time (ms)
Freq
uenc
y (k
Hz)
5000
300
150
L = 0mm
Time (ms)
L = 7mm
0 20 40 60 80 100
Definition of Damage Index Definition of Damage Index DIDI and Correlation Coefficient and Correlation Coefficient cc
Smart Composite System Laboratory The University of Tokyo
0.6
0.8
1.0
1.2
0 2 4 6 8 10 120 2 4 8 126
Cor
rela
tion
Coe
ffici
ent
1.2
1.0
0.8
0.610
Debonding Length (mm)14
0
20
40
60
80
100
120
140
160
180
0 2 4 6 8 10 12 14
Dam
age
Inde
x
160
Debonding Length (mm)0 2 4 8 10 126
14012010080604020
0
0
2
4
6
8
10
12
14
0 2 4 6 8 10 12 14
Dam
age
Inde
x
14
Debonding Length (mm)
0 2 4 8 10 126 14
12
10
8
6
4
2
00
Debonding Length (mm)
0.6
0.8
1.0
1.2
0 2 4 6 8 10 12
Debonding Length (mm)
0 2 4 8 126
Cor
rela
tion
Coe
ffici
ent
1.2
1.0
0.8
0.6100
L
(A), (B)
Bonded FBG(A)
Embedded FBG(B)
DamageIndex
CorrelationCoefficient
CorrelationCoefficient
DamageIndex
180
Damage Index Damage Index DIDI and Correlation Coefficient and Correlation Coefficient cc as Functions of as Functions of DebondingDebonding LengthLength
Results by embedded FBG (B) changes rapidly around L = 6mm, which indicates that the debonding passed above the FBG (B).
Smart Composite System Laboratory The University of Tokyo
(1) Read the waveforms detected by the damage monitoring deviceSAWD Damage Diagnosis SoftwareSAWD Damage Diagnosis Software
Smart Composite System Laboratory The University of Tokyo
(2) Calculate the damage area by the damage diagnosis softwareSAWD Damage Diagnosis SoftwareSAWD Damage Diagnosis Software
Smart Composite System Laboratory The University of Tokyo
Design allowable
Residual cyclic number
(3) Predict the damage growth by the residual life prognosis softwareSAWD Damage Diagnosis SoftwareSAWD Damage Diagnosis Software
Smart Composite System Laboratory The University of Tokyo
Verification by SubVerification by Sub--Structure TestsStructure Tests
Amp.Device
PC
Removable
Installing & cabling withFBG sensors/PZT
The system set-up was simulated for practical use in inspection or maintenance field
On ground (ex. hangar) On board permanently
Connected to the device
Size: 4000 X 2000 X 400 mm
To removable connector
Removable connector
O.F. & PZT cables
6
Smart Composite System Laboratory The University of Tokyo
Correlation Point ofPump Light and Probe Light
Feature of BOCDAHigh spatial resolution (5 cm in length: Normal Mode)
(2 mm in length: HR Mode)High speed sampling rate (10Hz)Multi-points strain sensing (random access)
The phases of the pump and the probe light waves change periodically, it make the correlation peak position on the fiber. At the correlation peak position, the pump and the probe light waves are synchronously frequency modulated and maintain the frequency difference.
Pump Light Prove Light
Freq
uenc
y
Optical Fiber
Strain
Distance
Inte
nsity
Probe Frequency
Strain
Distance
Inte
nsity
Probe Frequency
ACSACS--SIDE ProjectSIDE ProjectBOCDABOCDA HighHigh--Resolution Distributed Strain MeasurementResolution Distributed Strain Measurement
Mitsubishi Heavy Industries, University of Tokyo
SPIE Paper 6933-29
BOCDA Principle (Brillouin Optical Correlation Domain Analysis) developed by Professor Hotate
ΔνS=CSε+CTΔT
Smart Composite System Laboratory The University of Tokyo
Powersupply
Controlunit
Optical unit1. Bolted joint distributed strain monitoring
2. On-board type BOCDA system development3. Flight load monitoring using BOCDA system
Detect damage by distributed strain
Missing Fastener
Optical Fiber
Sensor
(2) On-board BOCDA system development
Structure life assessment
(3) Flight load monitoring using BOCDA system
Optical fiber sensor
BOCDABOCDA--SHM System DevelopmentSHM System Development
(1) Bolted portion monitoring
Monitor
Power Supply
Optical unit
Control unit
Monitor
Power Supply
Optical unit
Control unit
0
100
200
300
400
500
600
700
0 10 20 30 40 50 60 70 80 90
Time [sec]
Str
ain
[ue]
strain form BGS
Strain Gage
Smart Composite System Laboratory The University of Tokyo
BOCDA Distributed Strain Measurement ResultsBOCDA Distributed Strain Measurement Results
– It was observed the clear deference in distributed strain between the intact structure and that with a missing bolt.
⇒structure defects (missing bolt) was detectable by high spatial resolution BOCDA system.
-500
0
500
1000
1500
2000
10.7 11 11.3 11.6
Position [m]
Stra
in [με]
Intact#5 bolt removed
#5 bolt
X=11.0
X=11.3
Opticalfiber sensor
Strain gage
Smart Composite System Laboratory The University of Tokyo
<Flight condition>Pull upAlt: 15,000ft
<Measuring Condition>Dynamic sampling (60pt/sec)
On-board BOCDA system was successfully operated during flight conditions to assess structural load history
<Flight condition>Landing
<Measuring Condition>Dynamic sampling (60pt/sec)
-300-200-100
0100200300400
0 20 40 60 80 100
Time [sec]
Stra
in [με]
Strain from BOCDA
Strain Gage
-300-200-100
0100200300400
20 40 60 80 100
Time [sec]
Stra
in [με]
Strain from BOCDAStrain gage
Dynamic Flight Load MonitoringDynamic Flight Load Monitoring
Smart Composite System Laboratory The University of Tokyo
OutlineOutline(1)(1) Structural Health Monitoring Group,Structural Health Monitoring Group, NEDO Smart NEDO Smart
Material/Structure System Program (FY1998Material/Structure System Program (FY1998--2002)2002)
(2)(2) Structural Integrity Diagnosis and Evaluation of Structural Integrity Diagnosis and Evaluation of Advanced Composite Structures (ACSAdvanced Composite Structures (ACS--SIDE) SIDE) Project,Project, METIMETI Advanced Material & ProcessingAdvanced Material & Processingforfor NextNext--Generation Aircraft Structure ProgramGeneration Aircraft Structure Program(FY2003(FY2003--2007)2007)
(3) Integrated High(3) Integrated High--Resolution Distributed Strain Resolution Distributed Strain Monitoring with Embedded Optical Fibers in Monitoring with Embedded Optical Fibers in Composite (FY2007Composite (FY2007--))
Smart Composite System Laboratory The University of Tokyo
PPPPPP--BOTDABOTDA sensing systemsensing system
Neubrescope(Neubrex Co., Ltd)
Pre-pump Pulse Brillouin Optical Time Domain AnalysisDistributed strain measurement
Spatial resolution: 10 cm Sampling interval: 5 cmSensing range: > 1 km (whole length of optical fiber)
7
Smart Composite System Laboratory The University of Tokyo
大規模構造物への適用 (VaRTM成形中)
供試体内埋め込み
Vacuum Bag
T-II
S-II
T-I
S-I
Ligh
t Sw
itch
OSA
Light Source
(Path Change)PPP-
BO
TDA
2.1m
Strain Measurement During Strain Measurement During VaRTMVaRTM (Vacuum(Vacuum--assisted Resin assisted Resin Transfer Molding)Transfer Molding) Process of CFRP Stiffened StructuresProcess of CFRP Stiffened Structures
PPP-BOTDA and FBG Strain Measurements in a Single Fiber
Small-diameter optical fiber with high refraction index difference was effective to reduce the optical loss due to embedment
Comparison of Strains by FBG and PPP-BOTDA Measurement
Fiber Embedment
Smart Composite System Laboratory The University of Tokyo
大規模構造物への適用 (VaRTM成形中)
-1 0 1 2 3-300
-200
-100
0
100
200
300
Distance (m)
Stra
in (μ
ε)
Residual Thermal Strain Distribution
FBG
Embedded Region
Strain Measurement During Strain Measurement During VaRTMVaRTM (Vacuum(Vacuum--assisted Resin assisted Resin Transfer Molding)Transfer Molding) Process of CFRP Stiffened StructuresProcess of CFRP Stiffened Structures
PPP-BOTDA and FBG Strain Measurements in a Single Fiber
Comparison of Strains by FBG and PPP-BOTDA Measurement
Smart Composite System Laboratory The University of Tokyo
Damage Detection in CFRP Sandwich StructuresDamage Detection in CFRP Sandwich Structures
S. Minakuchi, et al., Journal of Sandwich Structures and Materials, 9 (1), pp 9-33, 2007.
Optical fiber acts as nerve to detect residual facesheet dent
Key1. Non-uniform strain is induced in optical fiber
in damaged area2. Facesheet dent is relatively wide
A limited number of optical fibers are sufficient to monitor whole structure
Smart Composite System Laboratory The University of Tokyo
Dent and Strain Distribution Dent and Strain Distribution –– Theory and ExperimentsTheory and Experiments
Facesheet: CFRP UT500/#135 (Toho Tenax Co.,Ltd., [(0,90)3])
Core : AL 3/16 5052-.001, Thickness : 20 mm(Showa Aircraft Industry Co.)
Adhesive films : AF-163-2K (3M Co.)
Displacement rate : 0.5 mm/minMaximum displacement : 0.5, 1 mm
Residual dent and strainwas well reproduced
Smart Composite System Laboratory The University of Tokyo
Response Simulation of SpectrumResponse Simulation of Spectrum
Calculate strain distributionalong embedded fiber
Calculate spectrumdepending on
measurement point
Simulation procedureDamage right above
embedded optical fiber
How spectrum changes when damage is introduced?
Developed optical software
Width of spectrum depends on damage sizeSmart Composite System Laboratory The University of Tokyo
Damage Detection TestDamage Detection TestSchematic of specimen Experimental set-up
Quasi-static indentation loadings were applied to introduce
simulated low velocity impact damage
Five kinds of maximum displacement :1, 2, 3, 4, 6.5 mm
Response depending on damage size was investigatedResponse depending on damage size was investigated
Diameter 12.7 mm
Facesheet: T700S/2500, [0/90]3SCore: Al 1/4-5052-.001
8
Smart Composite System Laboratory The University of Tokyo
ResultsResults -1 mm was applied-
Load-displacement curves
Top view of center of specimen
2D-plot of F-1dB
I II III IVV
VI
VII
VIII III
IIIIV V
VIVII
VIII
Residual dent depth0.3 mm
(Invisible)
One line nearest to loading pointresponded to invisible damage
Smart Composite System Laboratory The University of Tokyo
ResultsResults -2 mm was applied-Load-displacement curves
Residual dent depth0.8 mm
Number of responding linesand values of F-1dB increased,
as damage became large
Top view of center of specimen
I II III IV
III
IIIIV
2D-plot of F-1dB
V
VI
VII
VIII
VVI
VIIVIII
Smart Composite System Laboratory The University of Tokyo
ResultsResults -3 mm was applied-Load-displacement curves
Residual dent depth1.1 mm
Responses of VI and VII differed,confirming high resolution
of the proposed system
Top view of center of specimen
I II III IV
III
IIIIV
2D-plot of F-1dB
V
VI
VII
VIII
VVI
VIIVIII
Smart Composite System Laboratory The University of Tokyo
ResultsResults -6.5 mm was applied-
I II III IV
Load-displacement curves
Residual dent depth2.5 mm(Visible)
Occurrence of impactcan be detected
with high sensitivity
Top view of center of specimen
I II III IV
III
IIIIV
2D-plot of F-1dB
V
VI
VII
VIII
VVI
VIIVIII
Smart Composite System Laboratory The University of Tokyo
Application of SHM Technology to NearApplication of SHM Technology to Near--Future Future
Affordable Composite Aircraft and Affordable Composite Aircraft and SpacesraftSpacesraft
(1)(1) Structural Health Monitoring Group,Structural Health Monitoring Group, NEDO Smart NEDO Smart Material/Structure System Program (FY1998Material/Structure System Program (FY1998--2002)2002)
(2)(2) Structural Integrity Diagnosis and Evaluation of Structural Integrity Diagnosis and Evaluation of Advanced Composite Structures (ACSAdvanced Composite Structures (ACS--SIDE) SIDE) Project,Project, METIMETI Advanced Material & ProcessingAdvanced Material & Processingforfor NextNext--Generation Aircraft Structure ProgramGeneration Aircraft Structure Program(FY2003(FY2003--2007)2007)
(3) Integrated High(3) Integrated High--Resolution Distributed Strain Resolution Distributed Strain Monitoring with Embedded Optical Fibers in Monitoring with Embedded Optical Fibers in CompositeComposite StructuresStructures (FY2007(FY2007--))
Smart Composite System Laboratory The University of Tokyo
SHM Aerospace Industrial Steering Committee (SHMSHM Aerospace Industrial Steering Committee (SHM--AISC) AISC) SAE GSAE G--11 Committee11 Committee
• Manufacturers:– Boeing– Airbus– EADS– Embraer– Bombardier– Lochkeed Martin– FHI
• System Integrators:– BAE– Honeywell– Goodrich– GE
• Regulatory Agencies:– FAA– EASA– US AF– US Army
• Research Organizations:– Stanford University– Sandia National Lab– Air Force Research of Scientific Research– University of Tokyo– University of Sheffield– NASA– NRC Canada– RIMCOF
• Operators/Users:– ATA