second moment of area
second moment of area
(OP)
I have a horizontal section of pipe with another section of pipe joined at 90 degrees (mid span) and am trying to work out the stiffness of the section. Calculating the stiffness of the horizontal section is easy but can anybody help calculating the stiffness increase due to the vertical pipe?





RE: second moment of area
RE: second moment of area
Perhaps the Constant Deformation Method or the Method of Superposition.
These are just guesses at what I would look at as possible starting points. I really don't work with this type of thing normally.
Ed
www.engineerboards.com
RE: second moment of area
the 2nd mooment of inertia of a pipe is easy enough (look in any structures book, something like pi*r^3*t).
but i think you're more interested in the deflection of the end of the vertical pipe. Consider this pipe to be cantilevered off the horizontal pipe, which is subject to deflection to support the load applied to the vertical pipe (it sees a moment applied, this will cause the base to rotate, the axis of the undeformed vertical pipe will be normal to the deflected horizontal pipe) and the vertical pipe deflects under bending from the applied load.
RE: second moment of area
RE: second moment of area
or pi/4*(ro^4-ri^4) (... subs ro = ri + t)
RE: second moment of area
RE: second moment of area
This is valid of course only for tees properly reinforced for pressure usage.
It should be noted that the flexibility factor is used in piping analysis for the calculation of expansion stresses, so that the use of a factor not higher than one is a safe assumption. Personally would expect some reduction in stiffness (fl.factor>1), but, as also noted above, there are no data in the literature that I know of.
prex
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