I unfortunately can’t agree with that sentiment. Composites fail in very complex ways, with part of a tested sample failing in tension, another portion in compression and a third portion of that same sample in torque (possibly other ways too, depending on layup etc).
To bolster my point, listen to the video you’ve linked. Long before the steel has started obviously yielding, you can hear some of the CF fibers failing. It’ll take it, but your rated static strength is actually decreasing as those fibers in the downtube cross-section progressively fail. When failure in that video finally happens, it’s indeed at a high value… But it was only tested to failure once. And therein lies the insidiousness.
You’ve taken a jump on your mtb several times, jump, jump, jump, not hearing the gentle pinging in your bike’s headset area every time you land. One day you take the jump, as usual, but the headset and thus the forks & handlebars snap off. That’s a problem.
I totally agree with everything you are saying. But you have to consider the application of said material. A bike frame that bends is a failed part and it does not matter how much more force it can resist, it is now useless. I also am speaking of catastrophic failure by the way, as in there is no bike anymore after this crash type of incident. In these cases, I believe the carbon bike will endure a greater amount of force than a steel bike. And that’s also while being far lighter because at equal weight there is really no contest.
Well at this point we’re talking fundamental properties, yeah, CF is stronger in tension than steel or aluminum, for less weight.
I guess the crux of my argument is that details like layup and such are critically important, mainly cuz the applied force cannot accidentally be permitted to focus on a small area and break the fibers there, repeat repeat repeat, progressively destroying that part.
At least metals are generally consistent in their properties in multiple directions. I’d need a lot of reassurance, technically, before I flew on anything with a fully carbon wing, particularly as the wing ages.
I unfortunately can’t agree with that sentiment. Composites fail in very complex ways, with part of a tested sample failing in tension, another portion in compression and a third portion of that same sample in torque (possibly other ways too, depending on layup etc).
To bolster my point, listen to the video you’ve linked. Long before the steel has started obviously yielding, you can hear some of the CF fibers failing. It’ll take it, but your rated static strength is actually decreasing as those fibers in the downtube cross-section progressively fail. When failure in that video finally happens, it’s indeed at a high value… But it was only tested to failure once. And therein lies the insidiousness.
You’ve taken a jump on your mtb several times, jump, jump, jump, not hearing the gentle pinging in your bike’s headset area every time you land. One day you take the jump, as usual, but the headset and thus the forks & handlebars snap off. That’s a problem.
I totally agree with everything you are saying. But you have to consider the application of said material. A bike frame that bends is a failed part and it does not matter how much more force it can resist, it is now useless. I also am speaking of catastrophic failure by the way, as in there is no bike anymore after this crash type of incident. In these cases, I believe the carbon bike will endure a greater amount of force than a steel bike. And that’s also while being far lighter because at equal weight there is really no contest.
Well at this point we’re talking fundamental properties, yeah, CF is stronger in tension than steel or aluminum, for less weight.
I guess the crux of my argument is that details like layup and such are critically important, mainly cuz the applied force cannot accidentally be permitted to focus on a small area and break the fibers there, repeat repeat repeat, progressively destroying that part.
At least metals are generally consistent in their properties in multiple directions. I’d need a lot of reassurance, technically, before I flew on anything with a fully carbon wing, particularly as the wing ages.