lamborghini aventador repair techniques june the 28th enea
TRANSCRIPT
Lamborghini Aventador repair techniques
June the 28th
ENEA, Rome
2Luciano De Oto – ACRC Director 28.06.2011
ACRC
Aventador
Replaces 10-year success of Murcielago in March 2011
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ACRC
Lamborghini Overview – Monocoque LB83x
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RTM-Light
Braiding
reinforcements
Prepreg Class-A
Surface &
reinforcement
Lamborghini Overview – Monocoque LB83x
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Lamborghini Overview - RTM-Light process
Dry carbon fibers (CFK), Foam & Vacuum Bag are placed on a CFK male mould
The part goes into the oven to be preformed, using a vacuum bag. This bag is
removed after the preforming.
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Lamborghini Overview - RTM-Light process
In the assembly station the tool is closed, then the part is injected at low pressure
with an epoxy resin, and cured in the oven.
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Lamborghini Overview - Cobonding process
The part is de-moulded and used as “mold” for simultaneous curing and bonding
of external components in a co-bonding process (Patent Protected)
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Lamborghini Overview - Assembly
Monocoque bottom part exploded view
• Blue parts: “boxes” made with braiding technology, foam and
prepreg
• Red parts: Prepreg produced in autoclaveThese parts go for a thermal cycle into the autoclave
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Lamborghini Overview - Tub
Finished lower part of monocoque
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Lamborghini Overview - Roof
4
1
22
2
2
33
3
Roof exploded view
• The outer shell (n 1) is stratified with prepreg
• Braiding & Foam Parts (n 2 & 3) are winded in film adhesive
• The inner shell (n 4) is stratified
• The part is placed in the autoclave for a thermal cycle
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Lamborghini Overview - Monocoque
The roof and the lower part are bonded with an adhesive paste and
cured in the oven
The LB834 Monocoque is ready
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Lamborghini Repair Strategy
Classification of Lamborghini repair activities:
- Repair by various dealers at service centers worldwide
- Repair done on-site by specialist (“flying doctor”)
- Repair by Lamborghini specialized centers (5 only)
The kind of repair is strictly depending on the damage extent and classification.
For North America and Asia the flying doctor will be Heatcon
For Europe, Middle East and Africa the flying doctor will be Paolo Bisordi (Lamborghini)
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82x: Analysis of structural and body parts replacementLamborghini Repair Facilities worldwide
Specialized Centers
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82x: Analysis of structural and body parts replacementLamborghini Repair – Damaged Areas
Percentages of Murcielago damages in the net:
Front Impacts 53%
Rear Impacts 29%
Side Impacts 11%
Roof 7%
Action to be taken on basis of damaged components:
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82x: Analysis of structural and body parts replacementLamborghini Repair – Damaged areas
Current Murcielago accidents classification:
CFRP
CFRP
CFRP
CFRP
CFRP
CFRP
Steel
Steel
Steel
Steel
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82x: Analysis of structural and body parts replacementLamborghini Repair – Example of damage
FMVSS Crash test certification
Monocoque structure damage after crash at 56 Km/h (35mph):
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Lamborghini Repair – Main problems
Repair operations are performed in Lamborghini mainly by using prepreg (scarf
and patch method)
Major problems in the repair techniques on Automotive applications are the
followings:
- One-side only or limited accessibility
- Complex geometries repair
- Thermal mass overheating (Aluminum inserts)
- A-class surface requirements
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- Due to geometrical problems, is not
possible to access from both side during
the repair operations.
- Dedicated tooling such as caul plate to
match the original shape.
- Cosmetic (Class A) surfaces require
special considerations.
Special considerations to Lamborghini
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82x: Analysis of structural and body parts replacementSpecial considerations to Lamborghini
Aluminum inserts embedded in CFRP structure
(they can give problem during the curing
operation, working as heat accumulators)
NDI performed using portable A-scan
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Lamborghini – Repair practice
Real-life side pole impact scenario
Repair of full door sill structure and portion of floor
Heatcon on site at Lamborghini 2010, 2011
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Lamborghini – Repair area
• Damage simulated in driver side rocker panel,
within marked area
• For proof of concept area removed will be
reused as “new” part
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Lamborghini – Tools used
• Diamond cutoff saw
• Drill
• Die grander
• Sanding disks
• Sanding drums
• Knife
• Clecos and pliers
• Clamps
• Sharpie marker
• Router and base
• Measuring tape and ruler
• Shop vacuum
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Lamborghini – Tools used - continued
Hot bonder
Hot air generator
Heat blankets
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Lamborghini – Materials used
Consumable Materials
Bagging film
Breather cloth
Sealant tape
Scrim cloth
Release film – perforated
Release film – non-perforated
Flash tape
Lint free cloth
Mold release cleaner/solvent
Repair Materials
• Aluminum sheet for doublers
• Carbon prepreg ACG MTM49
• Araldite 2014-1
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Lamborghini – Mark damage area
• Mark damage area to be
removed
• Top and bottom markings must
be aligned
• Pilot holes can be drilled
through to align locations of
corner areas
• Silver or black sharpie markers
recommended
• Template of repair area may
be needed for marking
replacement part
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ACRC
Lamborghini – Remove damage area
• Use router or cutoff saw to
carefully remove damaged
area
• Cut radius in corners
• Maintain straight, clean edges
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ACRC
Lamborghini – Prepare bonding areas for doubler
• Remove foam core to depth
required for doubler
• Cutting knife and router can be
used for removal
• Use caution to avoid damaging
composite structure
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• Use solvent to remove mold
release material if required
• Use sanding disks and/or
sanding drums to prepare
surfaces for bonding of
doublers
Lamborghini – Prepare bonding areas for doubler
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Lamborghini – Prepare doublers for installation
• Measure and position doublers
to be installed• Note: Aluminum used for proof of
concept. Actual repairs will likely use
carbon doublers.
• Drill positions for cleco
fastners
• Cleco serves as temporary
fastener to hold doubler in
place during bonding
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Lamborghini – Prepare doublers for installation
• Use router to create slot if needed for
doubler positioning• Note: when possible try to minimize slotting in
structure by dimensioning repair part to avoid
interference
• Test fit part to structure, then remove
• Carefully mark doubler orientation for
positioning
• Aluminum sheets used for demo only
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ACRC
Lamborghini – Apply adhesive to doublers and replacement part
• Mix resin/hardener and apply to doublers
• Use clecos to hold doublers in position
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ACRC
Lamborghini – Position replacement part for bonding
• Insert and align part
• Slide doublers to position if
required
• Align part with structure
• Be aware of working time with
adhesive – minimum 1 hour is
typical with Araldite 2014-1
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Lamborghini – Apply adhesive to fill seams
• Ensure adhesive is applied
between all joining surfaces to
maintain structural strength
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Lamborghini – Use heat to accelerate curing of adhesive
• Construct “tent” with bagging
film around repair area
• Hot air system with hot bonder
used to apply heat
• Araldite 2014-1 times• 10C = 14 hrs
• 15C = 8 hrs
• 23C = 3 hrs
• 40C = 60 min
• 60C = 15 min
• 100C = 3 min
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Lamborghini – Taper sand to repair area
• Sand to prepare for installation of prepreg and/or wet layup
materials
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ACRC
Lamborghini – Install film adhesive over repair area
• Film adhesive should extend
slightly beyond carbon fabric to
be applied
• Use heat gun if required to
develop tack (stick to part)
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ACRC
Lamborghini – Cut and install repair fabric
• Cut strips of repair fabric at
appropriate fiber orientations
• Apply layer by layer, removing
backing film
• Work into corners to avoid
bridging
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ACRC
Lamborghini – Apply release film over repair materials
• Release film does not stick to material
• Avoid wrinkles
• Position thermocouples around repair area
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ACRC
Lamborghini – Positioning breather cloth over repair area
• Trim to required size
• Tape into position
• Install vacuum monitoring base
• Install vacuum source base
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Lamborghini – Apply bagging film to repair area
• Trim to required size
• Use sealant tape
• Pleat where needed
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ACRC
Lamborghini – Apply vacuum and check for leaks
• Vacuum level must be
adequate to perform repair
• Note: Due to vacuum leakage and
time additional time needed to
eliminate leaks, process was
stopped
• Next steps: Eliminate leakage,
and cure using heat. Then
inspect, and sand as necessary.
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Lamborghini – NDI Determine quality of repair
• Use appropriate NDI techniques
• X-ray methods
• Flash Thermography
• Ultrasonic scanning
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Lamborghini – NDI techniques
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Lamborghini – Phased array Scanning
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Lamborghini – Phased array Scanning
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Lamborghini – Phased array Scanning
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Lamborghini – Phased array Scanning
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Lamborghini – Phased array Scanning
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Lamborghini –Lamborghini – Phased array Scanning for complex geometries
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Lamborghini – Phased array Scanning for complex geometries
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Lamborghini – Phased array Scanning for complex geometries
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Lamborghini – Phased array Scanning for complex geometries
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Lamborghini – Structural bonding
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Lamborghini – Monocoque inspection
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Conclusions
Ultrasonic C-scan examination -> it was noticed that ultrasonic waves were greatly attenuated by the thermoplasticmatrix.This may be due to the high toughness resin used in the manufacture of this material. Therefore, existing ultrasonicequipment would have to be adapted for an improved examination.
Based on the literature review, ultrasonic technique was found to be one of the most commonly applied techniques forthe inspection of composite materials. It can reveal substantial subsurface flaws in composite materials due to superiorpenetrating power of ultrasound. By performing an interface C-scan or full waveform B-scan of the ultrasonic signalsreflected from the laminate and using an image processing procedure based on the two dimensional Fourier transform,the fiber orientation of the plies at different depths in the laminate can be mapped out.
Also ultrasonic methods pose no environmental or health risks. It can be used to obtain a permanent record ofdefects, can determine volumetric characteristics and location of defects. Ultrasonic probes can also be designed to testcomplex geometries. C-scan has been used to identify induced damage and failure modes in laminated, woven andthickness reinforced composites.However, ultrasonic techniques also have some disadvantages. The testing requires a highly experienced technicianor operator to properly acquire and interpret the data. A limitation of the ultrasonic C-scan technique for the detectionof damage in composite materials is the high attenuation caused by absorption in porous resin and wave scattering bythe fibers. The problem in conducting the analysis of ultrasonic signals generated in reinforced composite structuralcomponents lies in detecting a possible reflection induced by a defect in the structure while it is corrupted by thestructural noise mainly generated by the reinforcement. In addition, although non contact methods exist for testingthin laminates, in the majority of the applications the transducer must be in contact with the object with a couplant inbetween (i.e., through water – or gel – coupling layer). Thus, the testing is very slow compared to other techniquessuch as infrared thermography. Also, ultrasonic methods, especially those utilizing a scanning bed to obtain C-scans,can be quite expensive.
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Conclusions
CONCLUSIONS ON INFRARED THERMOGRAPHY Based on the literature review, it can be concluded that infrared thermography is a potentially powerful tool for inspection of concrete or timber structures rehabilitated with composite wraps or laminates, and for nondestructive inspection of FRP bridge decks.
The advantages of infrared thermography include: - Relatively fast data acquisition and easy data interpretation. - The acquisition of thermal images is done in a non-contact manner. - Thermal images contain pixel-by-pixel temperature data, thus enabling quantitative analysis of debonded areas if needed. - Thermography is effective for detecting near surface discontinuities such as delaminations, disbonds, impact damages, moisture zones and voids. - The inspection can be conducted from a distance without contact with the structure.
The disadvantages include: - The ability to detect defects decreases as the thickness of the FRP material increases. - The infrared camera is expensive. However, low cost non-radiometric cameras are now becoming available. -The depth and type of defect that can be detected is limited. -damage caused by impacts of less than 8 Joules were not detectable
Additional research work is required, especially on the image processing side, to be able to detect lowenergy impact damage. The main advantage of this technique remains in the fact that direct colourimages of the material inspected are generated. Although, such images may seem easy to interpret,in certain cases, image processing operations are necessary for proper thermograph interpretation
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Conclusions