Integrated Buildings & Structures

Should be an easy question, but I'd like to confirm what set of formulas for different shapes (circular, rectangular, I beam...) should be used along with the material's Poisson Ratio? I have read several papers suggesting different formulas, which seem to change a little with each author. So I'd like to be clear what the "standard" set would be for practicing engineers.

The most current I have found that look promising are based on "W.C. Young and R.G. Budynas, Roark's Formulas for Stress and Strain". One such example would say:

Thin-walled square tube: k= 20(1+v)/(48 + 39v), where v= Poisson Ratio.

This value would be used to calculate the effective area in shear for the different section shapes and different material.

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Stephen Cumminger
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I realize that my question may not have been phrased very well, so here is some additional context in hope someone can help.

I am performing a Finite Element Analysis on a structure using various beam shapes and material; and considering their performance. The analysis includes the effect of shear stress on deflections as per Timoshenko theory. When doing that, the material's Poisson ratio is used of course, plus an estimating factor that reduces the beam's cross sectional area to better reflect the "effective" or average cross sectional area used in shear. This factor is always less than one and varies with shape and if the material is hollow. Since I found a few different examples of Shear Correction Factors on the Internet, I wanted to reach out and see what the most respected source of information among practicing engineers may be for this type of information.

 

For example, this link shows various steel sections for Eurocode 3 with the effective areas for shear precalculated: http://www.upi2mbooks.hr/upi2mbooks.hr/pdfs/SteelSectionsEC3ENG.pdf
Specifically it has the cross-sectional area and the Shear Area parallel to the web (y-y axis) and flanges (z-z axis) separately. For my purposes, I can get the factors by dividing the Shear Areas by the total cross-sectional area. What I'm wondering is if there is something similar to what is in this link as an ASCE reference. Some references I have found provide Shear Areas by shape and others provide formulas based on shape parameters and the Poisson Ratio. I prefer the latter so that I can consider materials other than steel, but any well respected references would be appreciated.

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Stephen Cumminger P.Eng, C.Eng, M.ASCE
Principle Engineer
Middle Sackville NS
1902 4760165
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