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Too close to maximum deflection or not too close to maximum deflection

  • Thread starter yohnson
  • Start date
  • #1
3
0

Homework Statement


Calculating uniform and sometimes point loads on simple beams and the calculated beam deflections using ETLs (estimated tabular loads).

My question in simply if I have found a deflection that is .005" less than the given maximum deflection, is it so close that if I don't recalculate, will my professor think that I'm some kind of an engineering maverick/loose cannon? I'm not kidding, I seriously just don't want to be too close for comfort, and I don't know yet how close structural engineers like to get.


Homework Equations


ETL = [(M)(8)] / L

deflection = [(5)(ETL)(L3) / [(384)(E)(I)]


The Attempt at a Solution



Deflection found. too close?

actual deflection = .660" maximum deflection = .6666"
 

Answers and Replies

  • #2
Lok
555
23
If that is the maximum great, don't worry it is just fine, safety factors are still there.
 
  • #3
3
0
thanks, Lok!
 
  • #4
740
27
Just to put a perspective: A frame manufacturer I know tested a bare frame and got pretty much the calculated deflection. Then the other frames adjacent were built, and connected with purlins etc. Same test on original frame got about two thirds of the original deflection. Finally all the sheet cladding was added. Tested again, the deflection was about one third of the calculated deflection.
 
  • #5
3
0
pongo38,
That makes sense, I'm so glad. I turn in my final project tomorrow!
Thanks!
 

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