Recently saw sumpn on cable regarding nylon, kevlar, spider's silk, etc. and heard a nice quasi-mathematical description of *toughness*--forgot what it was, but it made sense at the time. Seemed refreshingly un-ambiguous. :) Had sumpn to do with total energy absorption, within some kind of elastic limit, and of course *hardness*, but I can't quite remember what it was. From what I just said, rubber could be regarded as tough, depending on how you weighted the various components of toughness.
Is the characteristic of toughness unambiguously defined/determined, like hardness? Perhaps there are different types of toughness??
Inyway, I would also like to know if there are "standard" home-shop tests for toughness. If there are indeed different types of toughness, how does one assess the desirable type in terms of application-- Eg, sword fighting, knife blades, band saw blades, end mills, circular blades, etc.
A good example: Endmills vs shears. Different toughness? And then, a large paper shear cutter, vs, a metal shear. I've seen paper shears, 10-20 foot long, blades weigh hundreds of pounds, really good expensive steel. Would a metal shear blade do just as well, or would you indeed want to*alter the toughness characteristics of the blade *just for paper* * ? We're talking paper 1 foot thick, btw. tia.