[TheForge] RE: triangles

[Schade]

On Sep 15, 2004, at 8:29 AM, Devon Headen wrote:

> I don't have a lot of experience with the acoustic properties of  
> metal, but wood I do. I build guitars. The denser and more rigid the  
> wood, the more sustain you will have (not saying a maple guitar always  
> has more sustain than mahogany, but if all of the joints/vibration  
> transfer points were identacal it would be). Since higher carbon  
> context means more rigidity (not sure about density here), I reasoned  
> that higher carbon content = louder and longer sustaining dinner bell.  
> Somebody straighten me out if I'm wrong.
> _______________________________________________
>

on rigidity.

clipped from the keenjunk site...

http://www.keenjunk.com/cgi-bin/hse/HomepageSearchEngine.cgi?url=http:/ 
/www.keenjunk.com/_junkyard/jp0103_5.htm;geturl; 
terms=elasticity||modulus||of

Tony

The modulus of elasticity for carbon steels is virtually the same at  
30,000,000 psi. Hard or soft, strong or weak, tempered or quenched or  
annealed. Up to the point that it bends permanently, a spring or blade  
made of A36 will deflect virtually the same as a spring made of  
quenched and tempered 5160 (under the same load). As Jim said, the  
stronger material will allow you to bend it farther to a higher stress  
level before it will bend permanently and not "spring" back to it's  
original shape. The stress level that it bends permanently at is called  
the yield stress. Yield stress varies dramatically for different steels  
and different materials. A-36 steel has a yield stress of 36,000 pounds  
per square inch. A572 grade 50 has a yield stress of 50,000 pounds per  
square inch. Quenched and tempered 440C stainless has a yield stress of  
270,000 psi. (grin) Alloy content and heat treatment DRAMATICALLY  
affect yield stress. But not moment of inertia of the shape or modulus  
of elasticity of the material.