Eovations's mineral/thermoplastic composite has a modulus of elasticity between 500,000 psi and 800,000 psi, but a modulus of rupture of zero. It can flex extremely well, but does not have a catastrophic failure mode. (Source: Eovations)
Which is worse for the environment, manufacturing these composite materials or logging the equivelent amount of wood?
I like the idea of composite bridges and buildings though. Perhaps people would not have lost that much with Hurricanes Katrina or Sandy. I'm sure the current cost differences will keep the materials out of construction for years to come.
Okay, I'm pretty sure that "the modulus of rupture is zero" is not a correct statement. "Modulus of rupture" is a measure of the load-carrying capacity of a beam. A material with a load-carrying capacity of zero would not be very useful.
The modulus of rupture formula is only correct up to the elastic limit, so presumably the meaning of the statement is that it yields before it breaks. That's also how I'd interpret the rather amazing statement that "it does not have a catastrophic failure mode." If it doesn't fracture under any circumstances, it's be a miracle material, and they should be contacting physics journals rather than Design News. But I think they are just saying that it yields before it breaks.
That being said, this sounds like a pretty neat material. Mineral-filled polypropylene is a fairly common (and reliable) engineering material. However, making it into an open-cell foam, and drawing it so that the polymer chains are oriented, is an interesting innovation.
Ann, this is an interesting material. It is impressive that it can be used like wood, using the same tools and fasteners. That should make acceptance easier. The hurricane resistance should be of much interest in areas where that is a problem. I know someone with a place in Florida, and although the structure is concrete and quite resistant, they had to replace windows with bullet proof ones. Other structures, those with conventional roofs, are a real problem. This material would help.
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