Re: [Harp-L] Re: Reed Stress and Temperature

[Mike Wilbur <mike@xxxxxxxxxxxxxxxxx>]

Ahh Hah !
Now we get to the Meat of the Coconut !

Mike Wilbur


> On Sep 24, 2014, at 6:04 PM, Vern <jevern@xxxxxxx> wrote:
> 
> I suppose that I should not have used âelasticityâ when referring to the âmodulus of elasticity, Youngâs modulus, E, stress divided by strainâ. Stress is pounds per square inch of cross-section and strain is inches of stretch per inch of length.  For brass, E is about 15.5 million pounds per square inch (PSI)  For steel, it is greater.  It is the same kind of animal but has a different numerical value in metric units.
> 
> E is greater at lower temperatures.  i.e. an equal amount of stretch produces a greater restoring force at lower temperatures. If you are thinking of âelasticityâ as the ease with which something stretches, then my usage is indeed misleading.
> 
> Vern
> 
>> On Sep 24, 2014, at 11:57 AM, Joseph Leone <3n037@xxxxxxxxxxx> wrote:
>> 
>> I would have thought the opposite. As a metal expands, don't the molecules get farther apart? Making the metal softer. Until the metal finally melts. 
>> Doesn't cooling force the molecules closer together. Making the metal tighter? How does tighter equate to 'more elasticity'? Doesn't seem to jive.
>> 
>> smo-joe 
>> 
>>> On Sep 24, 2014, at 1:23 AM, Vern wrote:
>>> 
>>> 
>>>> On Sep 23, 2014, at 3:52 PM, patpowers <patpowers@xxxxxxx> wrote:
>>>> 
>>>> Thanks Vern - I love a good debate! ;)
>>>> 
>>>> ââ.., but my point is all materials get stiffer, and lose elasticity, as temperature decreases.
>>> 
>>> They gain elasticity (the value of E goes up) as the temperature decreases.
>