Xray a Carbon Fiber frame
09-02-16, 08:46 AM
#26
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Carbon Fiber Frames are, Now, a Consumable , like super light wheels and chains & Cassettes.
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Last edited by fietsbob; 09-03-16 at 10:10 AM.
09-02-16, 12:54 PM
#27
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A friend was telling me about a test on a carbon composite structure. They broke the structure -- everybody in the building heard it go, "Boom!" But now they can't find what broke on CT scans or ultrasound.
Relevance: Probably time for a new frame. Somebody with an X-ray can tell you it's broke (lookee at that crack!), but they can't tell you it's not broke.
Relevance: Probably time for a new frame. Somebody with an X-ray can tell you it's broke (lookee at that crack!), but they can't tell you it's not broke.
09-03-16, 10:05 AM
#28
Junior Member
Except in cases where it is obvious there is a structural failure, the interpretation of any nondestructive test is entirely dependent on the training and experience of the one viewing the image/data. The interpretation of carbon fiber can be very difficult. Xray including CT is probably your best bet. Delamination is easier to find by using the tap test with an aluminum coin. Delamination is more of a thud sound whereas normal sounds like a tap. With either Xray or a tap test it would be preferred to have the image or data from a known good component to compare. I tap test my carbon fork occasionally before I ride. Other than a tap test the other modalities are probably too expensive to accomplish. The NDS inspector is compensated for taking the risk of giving the all clear on a component. Also, radiological techniques in the clinical setting are very different than industrial. If I suspect a component is damaged I would just replace it.
09-05-16, 12:17 PM
#29
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Get friendly with your local proctologist, he has one. I get one shoved up my butt every 5 years.
09-05-16, 08:58 PM
#30
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09-05-16, 09:23 PM
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09-12-16, 12:29 PM
#32
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A limitation of x-rays is that the image is generated by the total x-ray intensity lost due to absorbance along a line from the x-ray source to the film or digital sensor. The decrease in intensity is the same for a solid layer or several layers of the same total thickness and material, so something like delamination wont' show.
09-12-16, 12:29 PM
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carbon xray answer
We do carbon xray. last year alone we did over 12,000 xrays on carbon, there are two people that say you can't xray carbon; the people that don't have the technology and the people that can't read. There was an article about not being able to xray carbon in aerospace but this pertained to delamination or delayering not crack failure this is where the notion that xray wasn't the proper technique for crack like indications in carbon. Here are a few NDT disciplines that we use but are not reliable. Flir infrared, ultrasound, sonic (tapping with a coin unless it's a dog) & visual. Ultrasonic is not a good discipline for cracks but can be used for delamination, the only way to use ultrasound for crack like indications is to use sheerwave and as far as I know we are the only company messing around with that technology and havn't had conclusive results and we deemed it unreliable as a testing technique. There are only two places on this planet that will xray carbon bikes and it's us (cyclehaus) or spyder composites who we just purchased. An xray takes 5 min soup to nuts and has shown to have the best results and is the most economic to the consumer.
