Last thirty or so years, “carbon fiber” has seemingly become the answer to everything in the world of structures. Some months ago I saw “carbon fiber” reading glasses on sale at a pharmacy; on close inspection, it turns out that it *really* *did* have carbon fiber cloth. On even closer inspection, that cloth was a single layer, a strip about 1/8″ wide that was simply glued onto the exterior of a standard cheap plastic frame. I was unimpressed.
Aerospace and automotive engineers are integrating carbon fiber into everything to reduced mass. In aircraft and spacecraft that’s vitally important; in autos, less so. Sure, lower mass cars are good, but sometime the materials you’re replacing have other properties that make them better. Carbon fiber is strong, but it’s not ductile…. a steel or aluminum auto body would bend and crumple in a crash, where a carbon body would simply shatter. Additionally, broken carbon fiber spits out tiny little shards that are skin-irritant, eye- and lung-damaging. (This I discovered to my personal dismay many years ago at United Tech in California, with the result that all the clothes I was wearing at the time wound up in the trash.)
And for all carbon fibers strength in tension… it’s not worth diddly in compression. Behold:
Note that after the second item goes under the press, the people working near it are suddenly wearing respirators.
The carbon fiber fails fast here. This did not surprise me. The exact mechanism of failure, though, was a little surprising. It’s remarkably uniform.