Equivalent length of of column ?

  • Thread starter rad10k
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  • #1
rad10k
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Equivalent length of of column ??

Homework Statement



A Mild steel column has a cross section of 100 mm by 50 mm . Assuming a safety factor of 6 calculate the load that it can safely support?

Homework Equations



Rankines formula : W = Oc/K[1+a(AEe^2/I]


The Attempt at a Solution



My problem is with Ee = Equivalent length of column in millimetres

How do I find this value as the question does not give a length?

Thanks for any advice
 

Answers and Replies

  • #2
nvn
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rad10k: I think you cannot solve this if no column length is given. You also need boundary conditions to be given. Are you sure no length is given? If you are sure no length is given, then perhaps the only thing you could do is, assume Ee is a variable, and obtain W as a function of Ee, which would be a curve.
 
  • #3
rad10k
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Yes the question is an exact copy . I spoke to my tutor who informed me that I do not need a length for short columns so maybe im trying to used the wrong formula for which Eulers formula also asks for Ee so I cant use that. The only other formula I know of is the straight line formula but for that you need to be given the end conditions ie. pin ends .
 
  • #4
nvn
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No, even short columns need a length, and boundary conditions. Something seems amiss.
 
  • #5
pongo38
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Maybe all that is being asked for is the squash load from f=P/A. Who says that Rankine's formula is relevant?
 
  • #6
rad10k
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Nobody I was just just going to use that. I think I need to go get clarification on what exactly the question is asking for. thanks
 

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