5 ms·
Is bone particularly tough though? I would have guessed some of the harder woods would already surpass or at least match it.
by ginko 5y ago
Is bone particularly tough though? I would have guessed some of the harder woods would already surpass or at least match it.
- hgomersall 5y agoThere was a standing joke during engineering undergrad that wood-along-the-grain always came out best on all the material selection charts. Essentially the answer to all questions about what material to use was "wood along the grain". I suspect that wood genuinely is close to being that good and its consistency (and the tricky across-the-grain bit) is what stops it being used everywhere.
- thaumasiotes 5y agoWood is also more of a fire risk than other materials.
- dmos62 5y agoThis comes up when talking about the wooden skyscrapers being built. Maybe someone can elaborate, but, as far as I've heard, treated construction wood has pretty good fire-damage characteristics.
- Aromasin 5y agoWood is at the same time a combustible and fire-safe material. The required fire resistance of wood structures can be achieved by adding to the size of the structure, adding a protective cladding, using a non-combustible insulation material, or by improving the fire resistance of the wood structure with a fire-retardant treatment.
- _0w8t 5y agoSteel and iron are also combustible even if that requires a high temperature. During bombing of Dresden in WWII that contributed to massive sustained fires.
- _0w8t 5y agoWood is very predictable under fire. In addition it is a good isolator so the high temperature does not spreed that fast. So it is quite straightforward to engineer things to be safe and give enough time for firemen to arrive. Steel on the other hand not only looses its strength under high temperature, but it also conducts the heat very fast facilitating spread of fire. Accounting for that is non-trivial.
- jpitz 5y agoBy "still" I assume you mean "steel"?
- Jeff_Brown 5y ago> it is quite straightforward to engineer [wooden] things to be safe and give enough time for firemen to arrive. That time depends hugely on where you live.
- ceejayoz 5y agoWell, that's why local building codes exist. Don't build a ten story wood building two hours from the nearest fire station.
- Jeff_Brown 5y agoRight, but I'm thinking more of whether you live in a developed country with decent public services. In huge swaths of the world building with pure wood is asking for a lot of trouble. (Happily (?) it's too expensive in most of those regions to be very popular.)
- foobarian 5y agoAdd to that that "along-the-grain" also includes significant expansion and contraction due to humidity changes. I am in an old house where years of expand-contract cycles on the wood framing have managed to wiggle out nails in places to the point where they stick 1/4in above the drywall surface.
- lostlogin 5y agoEvery house here in New Zealand is wood, and humidity is pretty high. I have never seen this except for decking, where nails are a bad option. I’ve see nails move a lot after earthquakes (sort of tearing the framing and cladding). Maybe we don’t see this as the weather is nearly always humid as we don’t get a real winter (so we don’t have a humidity cycle)?
- foobarian 5y agoRight, it's all about the cycle. Our climate goes from intensely humid in the summer, to bone dry in the winter - both because cold air in the negative double-digit Celsius temps is physically dry, and because our heat is forced-air. Then there are periods of high A/C use which also dehumidifies the air.
- ad700x 5y agoI believe wood expansion is primarily across the grain. More than an order of magnitude difference between radial and longitudinal https://woodworking.stackexchange.com/questions/5871/which-direction-does-wood-expand https://woodworking.stackexchange.com/questions/5871/which-d... It varies significantly based on wood species.
- stronglikedan 5y agoConsidering there has yet to be a dental crown that's as strong as a natural tooth, I'd imagine it's pretty far up there on the toughness chart.
- ginko 5y agoTeeth aren't bones though.
- Jeff_Brown 5y agoIn particular, the fracture properties of tooth are very different from those of bone. If I had to make a house out of one of them, I'd choose bone.
- alexpotato 5y agoBit of a side bar but the physical properties of parts of the human body are just amazing. For example, the coefficient of friction for cartilage is 1/10 to 1/100 that of ICE [0] 0 - https://teambone.com/education/education-clinical/orthopedic-basic-science/articular-cartilage/ https://teambone.com/education/education-clinical/orthopedic...