Roark

[mech_eng_p]

Hi All,

I am looking for a formula to describe the stress in the centre of a circular plate, stiffened with a small pipe. Something like added section.

Roark formula 9(a), from table 11.2 is quite good if i compare the results with FEA, but that is just a flat circular plate.(without the ring...)

The ring stiffens the plate, so the plate will have less stresses at the centre.
Roark has something like underneath, but it doesn't describe the stress at the centre of the plate.

If I use Roark 9b here, the stresses are way off, compared to FEA.

Can somebody help me with a formula (roarks maybe?) describing the stress at the centre of the plate, where the plate is stiffened?

I am looking forward to hear from you!

 

[btrueblood]

Compare the stress for a flat plate of diameter 180 to that of a plate (edges fixed) with diameter (180 - 2*thickness).

 

[rb1957]

how does this plate attach to "the rest of the world" ? I assume the plate is loaded by pressure ??

Why not assume a simply supported plate ?? diameter 180mm, or 180-t, or 180-2t ...

another day in paradise, or is paradise one day closer ?

 

[MIStructE_IRE]

Where can I get a copy of these Roark formulae?

 

[msquared48]

From Roark - "Formulas for Stress and Strain".

Mike McCann, PE, SE (WA)

 

[rb1957]

"Where can I get a copy of these Roark formulae?"

I'd look into Roark's references, for this problem probably timoshenko "plates and shells".

another day in paradise, or is paradise one day closer ?

 

[MIStructE_IRE]

Thanks Guys