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Re: [Phys-L] Stress Calculation?



On 3/9/2013 5:35 AM, Chuck Britton wrote:
http://www.thingiverse.com/thing:51248

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If the first worm rotates as fast as 3600 rpm and its pitch is 1/8 inch, then its engagement patch advances along the perimeter of the matching gear at 1/8 inch per 1/60 second.

If this gear wheel were fixed in place, its engaged tooth would advance less than a half pitch before breaking. This would take less than 1/120 second. It could certainly advance more than 1/1000 of a pitch before cracking at the root for 1 millistrain. (1/8000 inch) This would occupy 1/60000 sec

If the second worm wheel's pinion were fixed in place, its engaged tooth would increase to a strain of 1 millistrain in 50/60000 sec.
The twelfth gear wheel would move its engaged tooth to a strain of 1 millistrain in (50^11/60000 sec.
How long would it take to break this final gear wheel tooth?

Longer than (50)^11 / (60000. 60.60.24.365) years or ~ 2.5Myr then....

Brian W