Lamborghini Aventador repair techniques June the 28th ENEA

Lamborghini Aventador repair techniques

June the 28th

ENEA, Rome

2Luciano De Oto – ACRC Director 28.06.2011

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Aventador

Replaces 10-year success of Murcielago in March 2011


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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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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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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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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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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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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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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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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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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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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 –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

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Lamborghini Aventador repair techniques June the 28th ENEA