Linear metal expansion - For an Old timer

AI Thread Summary
The discussion focuses on the thermal expansion of aluminum, specifically its coefficient of expansion, which is given as 22.2 x 10^-6 m/m K. For every degree Celsius increase in temperature, a one-meter length of aluminum expands by 0.0222 mm. The user is trying to relate this coefficient to practical dimensions, such as 2mm, and is confused about the calculations involved. They also inquire about the temperature change that would produce a specific expansion measurement. The conversation highlights the importance of understanding thermal expansion in the context of building materials.
DHA
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Hi all

I am a newbie here, so please go gentle

It is along time since I have had to use Thermal Co-efficients of expansion for various metals.

However, I am trying to tie in some figures I have been given to what I know to be reality.
i am sure that I am doing something basically wrong, or the whole theory of such science will hve to be re-written

Now I know that aluminium expands at a rate of 1 or 2 mm per metre ( depending on colour ) I am involved here with the flashings on buildings , so thicknesses from 0.9mm to 3mm thick )

Given that knowledge ( unless the building industry is wrong ) I have been given a co-eff of 22.2 x (10 power -6) m/m K (Not sure how to get -6 as supertext )

How do I relate that back to a dimension of 2mm or so that I am familiar with ( I am sure I can not count the right number of zeros ) but hey it's well over 40 years since I did this and a good 50 since I did it at school

Much appreciated

A confused Old Timer

DHA
PS Perhaps I should add ~ I am moving decimal point 6 places to left, then 3 to right (to bring to mm ) obviously wrong as it is no where near ??
 
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When you say 1-2mm expansion for 1 m bar, what is the temperature change producing this expansion?
 
given a co-eff of 22.2 x (10 power -6) m/m K
Hi DHA! http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

That means for every degree Celcius it is heated, each metre of length (and thickness) expands by 0.0000222 metres (i.e., by 0.0222 mm).

So a 100°C rise would see each metre of it stretch by 2.22mm.
 
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OK Forgot about temp difference, How thick am I ?

Thanks
 
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