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Suppose I have a 20mm pipe with water flowing through it. The pressure in the pipe is 0.5 MPa. The pipe widens at a certain point and contains a metal object that blocks the pipe but has a number of holes in it that the water can flow through. The total cross-sectional area of these holes is equal to the cross-sectional area of the 20mm section of the pipe.

I want to know if the metal object will withstand the pressure of the flowing water. The yield strength is 205 MPa and the water pressure is only 0.5 MPa but I am assuming that the pressure will be greater at the points close to the holes - is this correct? Is the pressure likely to be greater than 205 MPa, I feel like it is safe to assume that it won’t be, but I don’t have the knowledge or experience to make that assumption with confidence so I would like the input of those who do. Any comments on this would be appreciated!

EddieP
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1 Answers1

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Because the total area of the holes is the same as the pipe area, the pressure on the strainer is roughly the same as that of the water: 0.5MPa, with a fraction added due to friction around the holes.

That friction can be minimized by making the edges of the holes smooth.

So the plate stress can be calculated using Roark's formulas for stress and strain, Source , particularly tables 11.1 and 11.2 in chapter 11 page 430.

one can plug in the thickness of the plate, its diameter, and choose if it is simply supported or fixed, and calculate stresses and deflections, ignoring the perforations by adding a factor of safety of say 2.

But as a first estimate, a steel plate with a diameter of 30mm and a thickness of 2mm should handle this. there is a balance between the diameter of the strainer and its strength after the perforations are cut out.

kamran
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