Radiographic test for carbon fiber frame

Discuss light weight issues concerning road bikes & parts.
ScienceIsCool
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by ScienceIsCool

Or maybe demand a new Lamb wave inspection as the only way to be -really- sure the frame is safe. And then hope the test costs more than a new frame...

http://www.iop.org/EJ/abstract/0964-1726/11/2/310

I think your best bet is to find a structural composite engineer to act as an expert on your behalf. Then they can challenge your insurance company's nuttiness.

John Swanson

by Weenie


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DocRay
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by DocRay

Infin1ty wrote:John Swanson

Do you have any reference which i can use it against the insurance company? something that will help me in court
I'm sick of them, they took their time for about a year, i'm going to take a lawsuit against them.
[/quote]

You'll end up just paying lawyers.

There are test kits, they use fluorescein in water spray and a hand-held UV light with proper filter glasses-this is extremely common for fine crack detection, it just needs a dark room. However, this will not distinguish a paint crack from a CF crack, unless you are looking down the seat tube from inside out.

You may see loss of conductance across a real crack.

alienator
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by alienator

ScienceIsCool wrote:In really thin composite structures (like a bike) I hear that the only reliable way to detect cracks or delamination is with a dye penetrant test. Apparently, it's exactly what it sounds like. The part is soaked in a tagged (UV marker, magnetic, or other) fluid, cleaned, and then illuminated to check for otherwise invisible cracks.

X-Rays will miss small or thin cracks completely, just like when doctors miss bone fractures. Poor contrast, diffraction, and resolution make it difficult.

John Swanson


You could also use speckle holography to image vibrational modes. Such a technique can see defects far below the surface. It's possible to see the defects without holographic video made prior to the damage; however, prior holograms make the detection essentially certain as the damage will change the modes that will exist in the frame.

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Taz
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by Taz

If there is a crack you can see with the naked eye (the one you say there is on the seatmast) then you can have them perform Liquid Penetrant Testing (the plain one, no need for fluorescent etc) and prove there is a crack. It is a very cheap test.
The NDT report has to mention that crack (if it exists) and then if they insist that there is no problem ask them to give you an ispection report in which all the findings are documented and stating that the frame has been checked following the accident and it has been deemed safe to ride.
Most likely nobody will want to sign that.

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Taz
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by Taz

alienator wrote:
ScienceIsCool wrote:In really thin composite structures (like a bike) I hear that the only reliable way to detect cracks or delamination is with a dye penetrant test. Apparently, it's exactly what it sounds like. The part is soaked in a tagged (UV marker, magnetic, or other) fluid, cleaned, and then illuminated to check for otherwise invisible cracks.

X-Rays will miss small or thin cracks completely, just like when doctors miss bone fractures. Poor contrast, diffraction, and resolution make it difficult.

John Swanson


You could also use speckle holography to image vibrational modes. Such a technique can see defects far below the surface. It's possible to see the defects without holographic video made prior to the damage; however, prior holograms make the detection essentially certain as the damage will change the modes that will exist in the frame.


Guys it is a bike we are talking about here not a space shuttle. There are many ways to detect defects in composite materials (surface UT waves etc) but you have to take into account that:
a) the tests would cost a lot more than the actual bike
b) you local NDT lab will probably not have the equipment required to perform them.
c) It would be very difficult to find someone that can actually interpret the results of the tests. I am a level II in RT, UT, MT, PT and would not know what the h*ll to look for when testing a bike frame (especially with UT)

Infin1ty
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by Infin1ty

I live in Israel and checked which places are allowed to test composites materials in a radiographic method.
There are only 4 places, IDF (Israel Defence Force), IAI (Israel Aerospace Industries) and 2 more places which i could not find.
I checked the company website which the insurance company used for and searched on their site for the certification of the radiographic test (NDT).
the weird thing is that the certification states clearly that they are allowed to test for metals objects only and welds.
So that's mean they are not allowed to check for composites because composites are probably a very "sensitive" case and only 4 places in Israel are allowed to test using a radiographic method (NDT).

That's solved all my problems :)

cees
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by cees

well this test is one of our standard test when we have new contruction (for composite )
hence we showed it years ago in a video ,
but there also downside on the test little cracks are mostly
hard to see this can be solved by a another test .
but any one can let do this testing

at
dutch aerospace center in netherlands

NLR

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coloclimber
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by coloclimber

Take a flux capacitor at 1.21 gigawatts and ride down the steepest mountain at 88 miles per hour and you will go back in time and avoid the accident and resulting headache completely.

Seriously though- I feel your pain. I was hit by a car riding a personal gift from Lance Armstrong and saw some small paint chips on the head tube which could allude to a crack. Trek, with all of their research equipment etc., could not tell me whether the frame was safe or not- that is why they offered a replacement frame. This one has tremendous sentimental value so it is now hanging in my garage without being ridden for years.

I don't think its worth the time and cost of hiring an attorney to fight the insurance company just to see if the frame is viable by running further tests. Go out and get a replacement frame so you can ride.

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Registered Executioner
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by Registered Executioner

alienator wrote:
ScienceIsCool wrote:<snip>

You could also use speckle holography to image vibrational modes. Such a technique can see defects far below the surface. It's possible to see the defects without holographic video made prior to the damage; however, prior holograms make the detection essentially certain as the damage will change the modes that will exist in the frame.

Alienator dude, how do you make that sh*t up?

Why not just use a 4th dimensional torsion warp-ray set on stun to destabilize the composite matrix long enough for a spectral capture of the Higgs boson substrata?

Or is that technique proprietary to the speed-weaponry arsenal? :twisted:

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coloclimber
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by coloclimber

LOL. I am with Registered Executioner - this sh!t is getting out of hand.
We are talking about a freaking bike frame used for hobby and sport, are we not?

Infin1ty
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by Infin1ty

coloclimber wrote:Take a flux capacitor at 1.21 gigawatts and ride down the steepest mountain at 88 miles per hour and you will go back in time and avoid the accident and resulting headache completely.

Seriously though- I feel your pain. I was hit by a car riding a personal gift from Lance Armstrong and saw some small paint chips on the head tube which could allude to a crack. Trek, with all of their research equipment etc., could not tell me whether the frame was safe or not- that is why they offered a replacement frame. This one has tremendous sentimental value so it is now hanging in my garage without being ridden for years.

I don't think its worth the time and cost of hiring an attorney to fight the insurance company just to see if the frame is viable by running further tests. Go out and get a replacement frame so you can ride.

Hey, i already have a replacement frame, but the car that hit me also hit me on a lane that is specific for cyclists/runners, it's even a different route of the one used by car!, the woman just drove over it without looking...
anyhow, i don't pay for the attorney,it's my uncle.
i just want my money back,it was not my fault and why should i pay for it?

alienator
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by alienator

coloclimber wrote:LOL. I am with Registered Executioner - this sh!t is getting out of hand.
We are talking about a freaking bike frame used for hobby and sport, are we not?


Maybe you guys should chew fewer serious pills. No one suggested that all the tests mentioned were practical. We just mentioned some cool tests. So what?

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HammerTime2
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by HammerTime2

Sue the bastards for more than just getting your money back. They tried to screw you over - now it's payback time.

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