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Anonymous Poster #1

# Hoop Stress and Axial Stress

11/02/2017 6:56 PM

I'm designing a tank and wondering about the relationship between hoop stress and axial stress.

Thanks

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#1

### Re: hoop stress and axial stress

11/02/2017 7:00 PM

..."Circumferential stress or hoop stress, a normal stress in the tangential (azimuth) direction; Axial stress, a normal stress parallel to the axis of cylindrical symmetry; Radial stress, a stress in directions coplanar with but perpendicular to the symmetry axis."...

https://en.wikipedia.org/wiki/Cylinder_stress

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#2

### Re: hoop stress and axial stress

11/03/2017 5:15 AM

That's OK for cylindrical tank, usually the case but OP didn't say.

Could add that in that case, hoop stress is 2 x axial stress, no doubt it's in the Wiki somewhere, but it doesn't jump out at me. Wiki gives a fairly thorough treatment but a tad over-complicated for somebody just trying to get his general thoughts in order IMO.

Also it only applies to pressurised tanks, for a cylindrical vertical axis atmospheric tank the only axial stress is compressive due to the weight of the tank wall.

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#3

### Re: hoop stress and axial stress

11/03/2017 9:07 AM

The shape and orientation of the tank is fundamental to the answer, which have been withheld from the forum.

Temperatures, pressures and densities of the fluids to be contained are also fundamental, which have also been withheld from the forum.

Materials of construction are of great interest, as is the compatibility between the fluids present and the wetted surfaces from a corrosion resilience perspective.

What design code is the organisation using in pursuit of this design?

What "as built" information is available from previous designs that could be cloned onto this one?

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#4

### Re: Hoop Stress and Axial Stress

11/03/2017 9:43 AM

For a pressurized cylindrical tank:

Axial (or longitudinal) stress = pr/2t,

Hoop stress = pr/t

so hoop stress is twice axial stress.

https://www.engr.colostate.edu/~dga/mech325/handouts/pressure_vessels.pdf

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#6

### Re: Hoop Stress and Axial Stress

11/03/2017 10:18 AM

Very good, you get A+ on that one, as even I can understand the answer.

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#5

### Re: Hoop Stress and Axial Stress

11/03/2017 10:15 AM

I would, but I need both of them today.

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#7

### Re: Hoop Stress and Axial Stress

11/03/2017 11:09 AM

Sure I'm sending one over...

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#8

### Re: Hoop Stress and Axial Stress

11/03/2017 11:15 AM

LOL!

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#9

### Re: Hoop Stress and Axial Stress

11/09/2017 2:08 PM

You are designing a tank? Really? In which country do you live?

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#10

### Re: Hoop Stress and Axial Stress

11/09/2017 2:57 PM

Good question, old boy, good question. I suspect we scared him/her off rightly done.

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