please explain this photo

[Cateye]

This is one of the Boston Globe's photos of the year (http://www.boston.com/bigpicture/201...rt_2_of_3.html).
Can someone explain what happened to Mark's front wheel?

It was a prototype rim that is inflated with helium........it got a puncture.

[rydaddy]

Fatigue testing, still today, is a grey area in the polymer industry. I took a class on non-metallic manufacturing processes. The carbon fiber is reasonably well documented and straight forward, its the reinforcing plastic coating which throws the curve balls. Atmospheric pressure, humidity, applied force, and numerous other conditions all play a role. Zipp probably does top of the line testing, and still does not have all of the variables accounted for. The bicycle industry at this level constantly walks the line between weight vs. load.

I suspect the problem was creep, not fatigue.

:facepalm:

Not fatigue OR creep. Facepalms all around...

0:53 of the video shows it all. It's called impact.

[Halebopp]

Not fatigue OR creep. Facepalms all around...

0:53 of the video shows it all. It's called impact.

He's talking about that light fixture anectdote, not the crash.

[Halebopp]

And the "facepalms" every other post are annoying me. One step above "lol".

[Motobetird]

Post #38
-The scary thing is that they are starting to make airplane wings out of Carbon Fiber Reinforced Plastic (CFRP). Apparently manufacturers are confident in their fatigue testing at this level.

Manufacturers being confident? I dont think an R&D guy at that manufacturer would say it's safe. It's probably some business guy's interpretation of what the engineer told him. If/when failure occurs, the engineer will get the blame and the business guy will waltz off to another project, and cause more problems there also.[/QUOTE]


-- I forgot...on the scale of airplanes vs. Bike components the weight savings from going to CF from metal is in the 1,000 s of lbs opposed to bicycle components which is weighed in grams. Because of this they are able to use much more material. Basically, the 2 are not similar enough to compare because of the scale.

[Motobetird]

How is this relelvant? And what the hell is apoxy? And since I'm guessing the light fixture was only undergoing static loads I suspect the problem was creep, not fatigue.

:facepalm:

-- Epoxy, not apoxy. Brain fart due to my pronunciation. Epoxy is the shiny stuff they coat carbon fiber with. Which is why the technical name for what we just call "carbon fiber" is carbon fiber reinforced plastic.

--- And as for the creep, I believe you are correct. It's been a while since the schooling days.

[7bmwm3gtr]

Do people like to over-analyze things?

It's almost like those people who bring mathematical formulas and reasoning into "Which came first, the chicken or the egg"

[rydaddy]

He's talking about that light fixture anectdote, not the crash.

I don't know if you understand, I am talking about the impact the Zipp wheel made perpendicularly with Cav's wheel. Creep and fatigue are completely unrelated. A very high point load along the weak axis of the rim caused the rim to fail.

Do people like to over-analyze things?

So your "analysis" was a failure and now you choose to change the subject?

[brianbeech]

Do people like to over-analyze things?

It's almost like those people who bring mathematical formulas and reasoning into "Which came first, the chicken or the egg"

This has been solved: http://www.msnbc.msn.com/id/38238685...ience-science/

"It had long been suspected that the egg came first but now we have the scientific proof that shows that in fact the chicken came first," said Dr. Colin Freeman, from Sheffield University's Department of Engineering Materials..."

[Spring Water]

[puppypilgrim]

Thanks for posting video Quel! Wow. That's gotta hurt.

[Spring Water]

[plainsdrifter]

I can't believe the skid mark the guy on the far left at 00:32-36 leaves on the ground. Ouch.

Seb Hinault



i was bored