Expanding Hole

Discussion in 'Physics & Math' started by KilljoyKlown, Apr 14, 2012.

1. RealityCheckBannedBanned

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800
Hi again, mate.

Sorry if I am not making myself clearer.

If the surface 'wrinkles', the surface may stay the same 'area' but its ridges effectively make the 'fitting space' smaller diameter without the actual inner surface area changing much.

Then I also said that the inner diameter may not change because the inner surface layers may be 'compressed' and made a denser layer than the material behind it.

That's all I meant mate. Cheers!

Disclaimer Again: I do not know about the 'heating fit' side of things. I've only ever used (once) the 'cooling' method for the stud/bolt to go into such a hole.

.

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7,261

5. DinosaurRational SkepticValued Senior Member

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4,320
See my Post #8, where I suggested consideration of the circumference of both the inner & outer circles.

Isn't obvious that both circumferences expand as the washer is heated? If you think of the washer as made up of a large number of very thin rings, each ring would expand along the circumference.

If the inner circumference increases, the radius must increase.

I would expect the washer to get thicker (Id est: Difference between radii increases) with some expansion toward the center. I expect that expansion to be overwhelmed by the increase in circumference.

7. KilljoyKlownWhateverValued Senior Member

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7,261
Maybe it would help to think of the hole as an arch that will dissipate any force directed towards the center around the circumference of the inner surface of the ring. Whatever, I like your example. I am somewhat surprised that so many people believed the hole would get smaller. Did anybody notice the difficulty rating on this problem was only 4 out of 10?

8. RJBeeryNatural PhilosopherValued Senior Member

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3,953
...so if the washer was cut through on one side and the newly-cut edges were allowed to cross over (like a ribbon) then we could expect a shrinking hole?

9. EmilValued Senior Member

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2,789
It's a good question.
I think whether it is cut or not, similar behave. As a photo enlargement.
Otherwise it would appear some very high tensions inside the material.
But this is only an opinion.

10. keith1Guest

The material becomes molten before it expands by 1%?
The material puddles?
The hole decreases in the puddle?