modules de résistance

08:52 Sep 10, 2009 

See http://www.patentstorm.us/patents/5672828/description.html for use of "strength moduli" in an English-language patent. Google comes up with a number of other hits. Yes, Chris, they are strictly-speaking stiffnesses, rather then strengths but are sometimes unofficially called "strength moduli". The "modulus" parameter is a slightly different usage. I don't think the French is being that vague and, whatever it is translated as, it appears to be referring to these four moduli, which my printed notes (from Swansea, 1991) state "are basic properties of any material". The proper term for these is the "elastic moduli". However, it also says that one of these, E, is also called (among other things) the "elastic modulus", so it appears (and I remember it being mentioned) that "strength moduli" is sometimes used to avoid confusion, if somewhat imprecisely.

14:28 Sep 9, 2009 

As I recall, E is Young's modulus, K is bulk modulus, and G is shear modulus. These are all stiffnesses, not strengths. Nu is Poisson's ratio.

13:40 Sep 9, 2009 

Even if you're NOT interested, that AND its sister volume, The New Science of Strong Materials or Why you Don't Fall Through the Floor" make A Good Read. In Chapter 7, "Glue and Plywood or Mice in the Gliders", for instance, you learn why, for instance, mice in England were on the Germans' side and how the Ministry of Defence ordered an official issue of cats (on the British side) to overcome them.

13:34 Sep 9, 2009 

The issue over resistance vs. strength in general is by no means a clear-cut one, but if you haven't come across a specific term, double-check it in both your bilingual technical dictionary and a monolingual reference (or failing that, Google). In many of the examples you give under Chris's answer you can actually have either "resistance" or "strength", depending on context. However, in this case, I remember (vaguely) being told about an unofficial term "strength moduli", which use the symbols E, G, K and Greek letter nu (looks like a small v). If in doubt, I always tend to use whatever any English language patents referred to have used.

12:59 Sep 9, 2009 

For those of us poor linguists who are confused, take heart: engineers have been confused by strength, stiffness, resistance and hardness for centuries. Hardness is particularly, er, hard, and there is in fact no unit or combination of SI units which describes it. See "Vickers" or "Shore". Some materials can be stiff, but not strong, while others can be strong but not stiff, though to be fair, there is a correlation. "Toughness" is another tricky one. If interested (!) read JE Gordon's excellent book(s) on "Structures, or why things don't fall down".

12:44 Sep 9, 2009 

As stated under Chris's answer, the strength moduli are a specific group of four fundamental moduli (I forgot to mention Poisson's ratio below).