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erssk
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Euler's Long Column Formula

10/08/2008 9:01 AM

Just want to verify my calcs. I haven't done one of these for quit a while. What is Pcr of a column 12 foot tall made from 2.75" o.d. X .375" wall drill pipe. Assuming Grade X-95, 95kpsi yield, 105kpsi tensile minimums.

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erssk
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#1

Re: Euler's Long Column Formula

10/08/2008 11:56 AM

Also; One end is hinged other is free. Assume Young's modulus E = 31 x 10*6.

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ba/ael
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#2
In reply to #1

Re: Euler's Long Column Formula

10/08/2008 7:49 PM

The column is unstable if one end is hinged and the other is free. Pcr = 0.

If one end is fixed and the other is free, the effective length will be 24'. I'm not sure where you find drill stem with the properties you have stated, so the exercise is a bit academic.

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erssk
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#4
In reply to #2

Re: Euler's Long Column Formula

10/09/2008 9:48 AM

API X-95 drill stem. = 95kpsi/105kpsi.

Like I said haven't done one for a while so was not certain about end conditions. This is not a civil project. No code worries. Using 12' pipe hinged one end other end held by two chains for a boom truck.

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Codemaster
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#3

Re: Euler's Long Column Formula

10/09/2008 4:28 AM

Hello erssk

Formula is Pcr = (pi/Leff)2*E*I where Leff = effective length. You need to check the end conditions, but taking ba/ael's assumption effective length = 2*length, I make it 7459 lbf.

This is theoretical, for any sort of structural member building codes likely to want a safety factor of 3 - 4.

Cheers.........Codey

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erssk
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#5
In reply to #3

Re: Euler's Long Column Formula

10/09/2008 9:49 AM

see reply ba/ael

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