abschlussworkshop cfk-rumpf ng · leitprojekt cfk rumpf ng 15.02.2011 von 09:00 uhr – 17:00 uhr...
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Leitprojekt CFK Rumpf NG
15.02.2011 von 09:00 Uhr – 17:00 Uhr Golden Tulip Hamburg
Abschlussworkshop CFK-Rumpf NG
Infusion Technology for Bonded CFRP Repairs (for Aircraft Primary Structures)
Dr. Christian Hühne, Dirk Holzhüter, B. Kujak, Arne Hindersmann, Jens Bölke, Olaf Steffen
2Leitprojekt CFK Rumpf NG
Topics
Repair Environment
State-of-the Art CFRP-Patch Repair
Repair ConceptsDesign and Automation Infusion Repair
Summary
Outlook
Boeing Demonstration of Patch
Repair
Damage
by
Lightning
Strike
3Leitprojekt CFK Rumpf NG
Repair EnvironmentTemporary Conservation
Protection
of damaged
structure
against
moisture. Application
of waterproof
cover
immediately
after
detection
Only
temporary!
Repair with Temporary Life Time: „Field Repair“Structural
recovery
for
full
use
of part. This
repair
has to be
redone
at every
major
maintenance
check!
Permanent Repair: „Depot Repair“Full Repair
of Structure. Structure
is
equivalent
to original one
(Level of Equivalent
Safety)
http://www.martinaire.com/Hangar1.jpg
http://aviationdave.files.wordpress.com/
http://www.aviation.technomuses.ca
(Repair
Level) [nach Baker und Raymond]
4Leitprojekt CFK Rumpf NG
Repair Environment (EASA)Primary Structure
Safety
relevant, Failure
causes
total losse.g. Centre Wing
Box, VTP Bearings, Rudder, Fuselage
Secondary StructureStructure
relevant for
normal operation, Failure
does
not
cause total Losse.g. aerodynamic
Fairings
/ Flaps, Slats
Tertiary StructureReimaing
Structure, Failure
has low
impact
on operatione. g.Maintenance
covers
Repaired by OEM or certified Company
Redesign
and Certification
of Repair
necessarrye. g. new
Framecoupling
Repaired by OperatorBy
Structural Repair Manual (SRM)
No immediate Repair necessaryPart may
be
temporarily
removedFailure
Cascade
has to be
prevented
5Institute of Composite Structures and Apaptive Systems
State-of-the-art (Bolted Repair)
Bolted
Repair
•
Bypass
of Original Load
Path
by
Riveting
of One or
Two
Doublers
Advantage•
Good Recovery
of Strength•
Slight•
Fast Application•
Easy Certification
because
of Fail-Safe-Concept
Disadvantage•
Minimum Skin Thickness
necessary•
Steps
in Aerodynamic
Shape•
Complex
at edges
and pressure
vessels•
High Weight, Two
Sided Access necessarry
Examples•
Thick
aircraft
structures
(>3mm)
1. Damage Detection by NDT
2. Removal of Damage (Drilling, Grinding, Milling)
3. Riveting of Doublers
4. NDT
6Institute of Composite Structures and Apaptive Systems
State-of-the-Art CFRP-Patch Repair
Scarf
Repair
•
NDT, Removal of Damage, Manual Grinding
of Scarf, Cocuring
of Wet
Prepreg
Layup
or
conbonding
of Hard Patch
(separate Tooling
necessary), Prepreg
Technology favoured.•
Ramp
of Scarf
1:20 –
1:40
Adavantage•
Original Structural
behaviour
nearly
restored•
Flushrepair•
Excellent
mechanical
Performance
Disadvantage•
Extremely
complex
and time consuming•
Qualitymanagement
complex
(Travellorcoupons)•
A lot of healthy
Material has to be
removed
by
the
scarf
Weakening
of Structure? Examples•
Repair
of Flaps (A320)
1. Damage Detection by NDT
2. Removal of Damage by Grinding or Milling
3. Filmadhesive and Filler Plies cobonded or bonding of Hard Patch
4. NDT
7Leitprojekt CFK Rumpf NG
DLR - Concepts
ChallengesReduction
of Maintenance
Time
Reduction
of Maintenance
CostsCertification
of Bonded
Repairs
Reproducibility
/ Human FactorStructural
Performance
AimDepot Repair
Method
for
Primary
Structures
SolutionsAutomated
Repair
Process
Robust Repair
ProcessFail-Safe
Repair
Process
Repairs
done
todayRepairs
done
tomorrowDemonstration of Boeing 787 Repair
8Leitprojekt CFK Rumpf NG
DLR - Concepts
Machining
of Scarf
-
Laserscanning
of Surface- Surface
Reconstruction
of Real-Geometry- Design of Scarf- Generation of Machining
Data- Milling
of Scarf
(3-Axis or
7-Axis)
Design and Machining
Concept
Advantages
-
Digitized
Geometry
for
Automation
of Repair
Process
-
Digitized
Geometry
for
Tooling
Generation (Hard Patch)
- Digitized
Geometry
for
Documentation
-
Automated
Milling/Grinding
of Scarf
for
Minimization
of Human Factor
- Automated
Milling/Grinding
of Scarf
forMaintenance
Time Reduction
9Leitprojekt CFK Rumpf NG
DLR - Design Concept
Removal of Damage / ScarfingLaserscanning
of 3D-Surface
Scanning
by
Perceptron
V5 Laserscanner:Absolute Precision: ~45μm
ATOS 3D-Scanning System
Manufacturer: GOM
*
*Source: EADS
or
10Leitprojekt CFK Rumpf NG
DLR - Design Concept
Virtual Design of RepairSurface
reconstruction
in CATIA V5
Design of Scarf
by
parameterized
Construction
Pointcloud Triangulation Real-Surface
Scarf-DesignParameter Input Machining
Data
11Leitprojekt CFK Rumpf NG
Aligning
of 3D-Data
Preparation of Damaged Area for Bonded Repair
Focussing
of 3D Data on relevant RegionReduction
of 3D-Data DensityTriangulation
of 3D-Point CloudReconstruction
of real GeometryChecking
of deviationDesign of Tapered
Repair
based
on real 3D-Shape
DLR – Machining Concept
Damage
Removal by
Milling
of StructureStructure
prepared
for
Patchrepair
Process
demonstrated
on unstiffened
Panel
Automated
Positioning
andBonding of Repairpatches
Process
demonstrated
on unstiffened
Panel
12Leitprojekt CFK Rumpf NG
Hard-Patch
Repair
Characteristik- Bonded
repair- Cured
Patches- Automation of Process- One Sided Access only
Hard Patch RepairRepair
Concepts
Machining
of Scarf
-
Laserscanning
of Surface- Surface
Reconstruction
of Real-Geometry- Design of Scarf- Generation of Machining
Data- Milling
of Scarf
(3-Axis or
7-Axis)
Design and Machining
Concept
Advantages
- Assembly
Possible
from
One Side
-
Improved
Mechanical
Performance via Double Lap
Joint
- Improved
Safety
via Double Lap
Joint
13Leitprojekt CFK Rumpf NG
Hard Patch Repair
Hard Patch Repair ConceptMaximum of 3 Repair
Patches
(outer
Patch
optional)
Inner Patch
Inserted
via Elliptic
RepairholePositioning
of Centre and Outer
Patch
Aligning
by
Middle
Patch
and Two
Drill HolesClosing
of Drill Holes
by
Two
Blind Rivets
14Leitprojekt CFK Rumpf NG
Hard Patch Repair
Hard Patch Repair3D-Demonstrator
CNC-milled
Scarf
Based
on Scanned
Surface
Hard Patch
Repair
with
Inner
and Centre Patch
Hard Patch
Repair
withInner, Centre, and
Outer
Patch
16Leitprojekt CFK Rumpf NG
Infusion Repair
-
Infusion of Positioned
Preform- Cobonding
of Patch
and Adhesive- One Sided Access only- Low Assembly
Tolerances
Infusion-Patch
Repair
Repair
Concepts
Machining
of Scarf
-
Laserscanning
of Surface- Surface
Reconstruction
of Real-Geometry- Design of Scarf- Generation of Machining
Data- Milling
of Scarf
(3-Axis or
7-Axis)
Design and Machining
Concept
Advantages
-
Easy Repair
Process
via Infusion
of Patch
- No Patch
Tooling
necessary
-
Flexible Patch
for
Repair
of Double Curved
Structures
- High mechanical
Performance
- One Sided Access only
necessary
17Leitprojekt CFK Rumpf NG
Cobonding Infusion Repair ConceptBonding of Filler
Plate
Insertion of Film AdhesiveInsertion der Preform
(with
Overplies)
Single Sided VacuumbaggingInfusion of PreformCo-Curing
of Adhesive
and Patch
Infusion Repair
Preform
Grundplatte(AL oder GFK)
StructurePatch
18Leitprojekt CFK Rumpf NG
Infusion Repair
Evaluation of Mechanical PerformanceCoupon Specimen
EN6066
Easy ManufacturingEasy Testing
(1-Axis Tension)
Testing
of Scarf
not
AdhesiveQuantative
Evaluation of Joint
Surface
Analytic
of Break Surface
Patch
Parent
Adhesive
Void
Overply End of Adhesive
Parent
Standard Set of
En6066 Coupons
19Leitprojekt CFK Rumpf NG
Infusion Repair
Evaluation of mechanical PerformanceARAMIS
Evaluation of Surface
StrainfieldStrain
Gauges
for
Local
Strains
0°/90°
0°/90°90°
/0°
90°
/0°+45°/-45°
+45°/-45°
-45°/+45°
-45°/+45°
-45°/+45°
25kN 35kN
20Leitprojekt CFK Rumpf NG
Infusion Repair
Detail TestingQuantification
of Geometry
Influence
Scarf
Angle, Elliptic
RepairsEvaluation of Repair
Process
Verification
of Doubler
ConceptsValidation of Patch
Lay-Up
Ply-by-Ply
/ Cupped
MaterialsDry
Fabrics
e.g. G0926, G1157 (Hexel)
Dry
NCF from
Saertex
(Biax)Resin: RTM6 (Hexel), LY (Huntsman) Adhesive: FM300 (Cytec), Hysol
EA 9596 (Henkel)
21Leitprojekt CFK Rumpf NG
Infusion Repair
Microscopic EvaluationCobonding
Good Bond Line, no VoidsHard Patch
(State-of-the-Art)
Good Bond Line, some
Voids
Mechanical Evaluation (Coupon)Infusion Repair
has equal
Mechanical
Performance compared
to Hard Patch
About
80% total Load Recovery
has been
achievedundamaged
State-of-the-Art
DLR-Concepts
Load Recovery
ParentBond Line
Patch
Bond LinePatch
Parent
22Leitprojekt CFK Rumpf NG
Infusion Repair
3D-Infusion Repair Process Demosntration
Cocured
Patch
CNC-milled
Scarf
based
on Scanned
Surface
23Leitprojekt CFK Rumpf NG
Summary
DLR is certified for changes on our own aircrafts (EASA part 21,25) e.g. on our Do228, Dassault Falcon, Airbus A320
State-of-the Art lacks a Bonded Repair Solution for Primary Structures to overcome „Designed for Bolted Repair“- Design-Rule
Repair ist strongly driven by Certification Requirements
Design and Machining Concept improves Repair Quality, Documentation and allows Process Automation as well as new Geometries
Infusion Repair reduces Process Complexity for curved Parts drastically by equivalent mechanical Performance
24Leitprojekt CFK Rumpf NG
Outlook
Development of Repair Method for Certification Process
Development of Process Chain for Automated Repair Process
Demonstration of a Full Automated Repair Process on a CertifiedAircraft Structure
Inflight Testing of Repair
25Leitprojekt CFK Rumpf NG
Thank you for your Attention!
26Leitprojekt CFK Rumpf NG
Contact Data
Expert Repair: Dirk Holzhüter
Phone: 0531 295 2319
Email: [email protected]
Expert Joining: Dr. Axel Fink
Phone: 0531 295 2308
Email: [email protected]
Expert Manufacturing: Michael Hanke
Phone: 0531 295 2303
Email: [email protected]
Head of Department Composite Design: Dr. Christian Hühne
Phone: 0531 295 2310
Email: [email protected]