Improving In-Service Inspection of Composite … In-Service Inspection of Composite Structures ......
Transcript of Improving In-Service Inspection of Composite … In-Service Inspection of Composite Structures ......
FAA Hughes Technical Center
Dennis RoachSandia National Labs
FAA Airworthiness Assurance Center
Improving In-Service Inspection of Composite Structures
CACRC Damage Assessment & Quality Inspection Task Group Update
Improving In-Service Inspection of Composite Structures
CACRC Damage Assessment & Quality Inspection Task Group Update
FAA Hughes Technical Center
ITG Team ParticipantsITG Team Participants
CACRC Inspection Task Group Members:
John Hewitt – Airbus (Co-chair)Jim Hofer - BoeingJeff Kollgaard – BoeingKirk Rackow - Sandia Labs AANCDennis Roach - Sandia Labs AANC (Co-chair)Glae McDonald - US AirwaysDarrell Thornton – UPSRichard Watkins - Delta Air LinesBob Stevens – United AirlinesEric Bartoletti – American Airlines Alex Melton - Northwest AirlinesAna Tocalino - Embraer
Dave Galella, Al Broz, Rusty Jones, Larry Ilcewicz – FAA
FAA Hughes Technical Center
• Composite NDI Handbook– Complete (SAE ARP5089); requires update
• Industry wide NDI Reference Standards– Complete (SAE ARP5506 & 5507; DOE report distributed in
June 2004)
• NDI Assessment: Honeycomb Structures– Experiments completed in 2007– DOT report in progress
• NDI Assessment: Solid Laminate Structures– Experiment development completed
• Miscellaneous Ongoing and Planned Studies– Detection and quantification of weak bonds– Affect of porosity, repairs & other impediments on NDI– As required to support main tasks & other task groups
CACRC Inspection Task Group ActivitiesCACRC Inspection Task Group Activities
FAA Hughes Technical Center
Composite Inspection Reference Standards
Composite Inspection Reference Standards
• Industry-wide composite reference standards developed to support damage assessment & inspection – honeycomb & solid laminate
• SAE Aerospace Recommended Practices (ARP 5605 & 5606) - adopted into Boeing and Airbus NDT Manuals
• Improve inspections of composite structures via introduction of advanced NDI methods
• Provides consistent approach to composite inspections - harmonized approach by OEMs worldwide
Optimized NDT Reference Standards
Assessed all construction scenarios and determined the variables that affect NDI – final
NDI Reference Standards designed accordingly
FAA Hughes Technical Center
Composite HoneycombFlaw Detection ExperimentComposite Honeycomb
Flaw Detection Experiment
1) how well current inspection techniques are able to reliably find flaws in composite structures
2) the degree of improvements possible through the integration of more advanced NDI techniques and procedures.
Utilize airline inspectors to establish industry-wide performance curves that quantify:
• Statistically relevant and realistic flaw profiles• Blind application of techniques to study hits, misses,
false calls, and flaw sizing
FAA Hughes Technical Center
S-9 Sondicator (LFBT)V-95 Mechanical Impedance Analysis
Conventional NDI Devices
Automated Tap HammerManual Tap Hammer
FAA Hughes Technical Center
Thermography
MAUSSystem
SAM System
Shearography
Wide Area and C-Scan Inspection MethodsWide Area and C-Scan Inspection Methods
PE Phased Array UT UT Wheel Array
UltraImage Scanner
FAA Hughes Technical Center
MAUS Image
Shearography (LTI) Image
Ultrasonic Wheel Array
SAM Image
Thermography (TWI) Image
FAA Hughes Technical Center
Performance of Multiple Devices forA Single Type of Test Specimen
Performance of Multiple Devices forA Single Type of Test Specimen
Results - evaluate performance attributes1) accuracy & sensitivity (hits, misses, false calls, sizing)2) versatility, portability, complexity, inspection time (human factors)3) produce guideline documents to improve inspections4) introduce advanced NDI where warranted
Comparison of Advanced Inspection Techniques withBest Conventional NDI Result on 9 Ply Carbon
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.5 1 1.5 2 2.5 3
Flaw Size (Dia. in Inches)
Prob
abili
ty o
f Det
ectio
n
Thermography MAUS IV Shearography CATT S.A.M. Wichitech DTHFalse Calls 744000 4.4
FAA Hughes Technical Center
Cumulative PoD - Woodpecker for All Panel Types
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.5 1 1.5 2 2.5 3
Flaw Size (Dia. in Inches)
Prob
abili
ty o
f Det
ectio
n
3 Ply Fiberglass
Cumulative PoD - Woodpecker for All Panel Types
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.5 1 1.5 2 2.5 3
Flaw Size (Dia. in Inches)
Prob
abili
ty o
f Det
ectio
n
3 Ply Fiberglass 3 Ply Carbon
Cumulative PoD - Woodpecker for All Panel Types
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.5 1 1.5 2 2.5 3
Flaw Size (Dia. in Inches)
Prob
abili
ty o
f Det
ectio
n
3 Ply Fiberglass 3 Ply Carbon 6 Ply Fiberglass
Cumulative PoD - Woodpecker for All Panel Types
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.5 1 1.5 2 2.5 3
Flaw Size (Dia. in Inches)
Prob
abili
ty o
f Det
ectio
n
3 Ply Fiberglass 3 Ply Carbon 6 Ply Fiberglass 6 Ply Carbon
Cumulative PoD - Woodpecker for All Panel Types
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.5 1 1.5 2 2.5 3
Flaw Size (Dia. in Inches)
Prob
abili
ty o
f Det
ectio
n
3 Ply Fiberglass 3 Ply Carbon 6 Ply Fiberglass 6 Ply Carbon 9 Ply Fiberglass
Cumulative PoD - Woodpecker for All Panel Types
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.5 1 1.5 2 2.5 3
Flaw Size (Dia. in Inches)
Prob
abili
ty o
f Det
ectio
n
3 Ply Fiberglass 3 Ply Carbon 6 Ply Fiberglass 6 Ply Carbon 9 Ply Fiberglass 9 Ply Carbon
Performance of Single Device (Woodpecker)Over Range of Test Specimen Types
Performance of Single Device (Woodpecker)Over Range of Test Specimen Types
FAA Hughes Technical Center
Purpose• Determine in-service flaw detection capabilities: 1) conventional NDT
methods vs. 2) improvements through use of advanced NDT. • Optimize laminate inspection procedures.• Compare results from hand-held devices with results from scanning
systems (focus on A-scan vs. C-scan and human factors issues in large area coverage).
• Provide additional information on laminate inspections for the “Composite Repair NDT/NDI Handbook” (ARP 5089).
An Experiment to Assess Flaw Detection Performance in Composite Laminate Structures
An Experiment to Assess Flaw Detection Performance in Composite Laminate Structures
A380 Section 19
737 Composite Horiz. Stabilizer
FAA Hughes Technical Center
Thick Laminate With Complex & Simple TaperThick Laminate With Complex & Simple Taper
FAA Hughes Technical Center
Specimen Set - Flaw Detection in Solid Laminate Composites
Specimen Set - Flaw Detection in Solid Laminate Composites
Thickness Range:12 – 64 plies
Simple Tapers
Complex tapers
Substructure Flaws
Curved Surfaces
Array of flaw types
NDI Ref. Stds.
FAA Hughes Technical Center
Composite NDI & Laminate Repair Systems –Compare Mechanical & NDI Performance
Composite NDI & Laminate Repair Systems –Compare Mechanical & NDI Performance
Comprehensive evaluation of composite repair and associated NDI technology to ensure proper mesh between structural integrity & flaw detection
Strain field & repair efficiency assessment vs.
NDI findings
0
2000
4000
6000
8000
10000
12000
0 5000 10000 15000 20000 25000 30000 35000
Repaired Panel #9Ultimate Failure Test
Gage 19 AxialGage 22 AxialGage 17 AxialGage 24 Axial
Stra
in (M
icro
stra
in)
Load (lbs)
Uniform Axial Strain Outside of Repair
Strain at Center of Patch
Strain at Edge of Patch
Strain in Patch - Solid Geometric ShapesSrain in Parent Material - Open Geometric Shapes
Strain Next to Patch
Ultrasonic C-Scan
Uniaxial carbon graphite; plies plus one repair
FAA Hughes Technical Center
Use of NDI to Quantify Porosity Levels & Assess Mechanical Properties vs. PorosityUse of NDI to Quantify Porosity Levels &
Assess Mechanical Properties vs. Porosity
• Intercompare mechanical tests, NDI & acid etch methods to assess porosity, strength and fatigue life
• Use of NDI tests to calculate mechanical properties
• Use of advanced NDI to improve quantification of porosity (stratified porosity that may exist in a repair)
Carbon Weave
FAA Hughes Technical Center
1 2
Pristine -Best
1 2
30% MR Dilution
70% MRDilution
1 2
66% MRScreen
1 2
33% MRScreen
1 2
100 MR
1 2
Room Temp.
1 2
Characterize Bonded Joints:Quantify Adhesive Strength
Characterize Bonded Joints:Quantify Adhesive Strength
TTU of Weak Bond Specimens Show Trends
FAA Hughes Technical Center
Angle Beam Ultrasonic Spectroscopy (ABUS)Angle Beam Ultrasonic Spectroscopy (ABUS)
• Compare received and transmitted waveforms in frequency domain; study frequency/amplitude shifts & change in damping in FRF
• Oblique wave (broadband UT beam) introduces shear stress in the bond line
• Difference between longitudinal wave and shear wave interrogation
-35
-30
-25
-20
-15
-10
-5
0
2 3 4 5 6 7 8
Bad bondGood bond
Normal incidence reflection coefficient
Frequency (MHz)
Am
plitu
de (d
B)
-40
-30
-20
-10
0
0 2 4 6 8
Bad bondGood bond
10Frequency (MHz)
Am
plitu
de (d
B)
Oblique incidence reflection coefficient
Frequency and Amplitude Shifts Differentiate Bonds
Negligible Affects on Normal Wave (?)
FAA Hughes Technical Center
Future Direction of CACRC Damage Assessment & Quality Inspection Task Group
Future Direction of CACRC Damage Assessment & Quality Inspection Task Group
• Detection of Barely Visible Impact Damage (BVID); determining extent of composite damage → driven by visual detection
• Enhanced visual inspection• Inspection of scarfed composite repairs; in-process QA• Inspection of fastened repairs to composite structure (in-
process QA; no current post-repair NDI requirement)• NDI vs. Damage Tolerance vs. Residual Strength – assess
structural integrity (focus on particular materials?)• NDI of adhesive bonds (“kissing” disbonds; weak bonds)• Ascertaining deterioration of material properties due to
environmental exposure (temp., moisture, chemicals, stress)
FAA Hughes Technical Center
Future Direction of CACRC Damage Assessment & Quality Inspection Task Group
Future Direction of CACRC Damage Assessment & Quality Inspection Task Group
• Detection of fluid ingress• Quantification of porosity (ref. stds. are critical)• Detection of matrix micro cracking hidden beneath painted
surfaces• Rapid, large area inspection methods (improve POD; decrease
false calls)• Methods to inspect highly attenuative materials (weaves, thick
structures, multi-layered structures) – proprietary issues?• Utilization of SHM techniques• Evaluating NDI performance - assessing conventional NDI in
light of advanced NDI methods
FAA Hughes Technical Center
Future Direction of CACRC Damage Assessment & Quality Inspection Task Group
Future Direction of CACRC Damage Assessment & Quality Inspection Task Group
• Optimization of NDI procedures; improved documentation and guidance
• Training – knowledge of hardware & procedures; use of “qualification standards”; industry standardization
• Ramp NDI – qualified personnel; equipment availability• Implement a database – trends assessment
FAA Hughes Technical Center
CACRC Inspection Task Group Update and Overview
CACRC Inspection Task Group Update and Overview
Dennis RoachSandia National Labs
FAA Airworthiness Assurance Center(505)844-6078