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Rectangular Tank

Rectangular Tank

Rectangular Tank

(OP)
I am designing a rectangular tank and need to have it comply using Mohr's Stresses formulas. I know of some FEA that could do something but according to ASME appendix 13.
Meygesy' PV handbook has a simplified method

Tanks has to comply to this equation....
S = 0.5 (Sy + Sx) ± [0.25(Sy – Sx)2 + Ss2]0.5

JL

RE: Rectangular Tank

Do you have a question?

Patricia Lougheed

******

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RE: Rectangular Tank

(OP)
Do you know of some way of doing this analysis in an efficient manner. Where to read about rectangular steel tank design?

JL

RE: Rectangular Tank

won't your FE output principal stresses ? von Mises stresses ??

if think your equation is "just" the principal stress equation, and if your FEA outputs max (and min) principal stresses that should do it. no?

RE: Rectangular Tank

(OP)
What good software would produce those outputs with calcs showing too? I am green in FEA Software.

JL

RE: Rectangular Tank

Why wouldn't you do something that simple by hand?

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

RE: Rectangular Tank

I was thinking there was a recent post on the subject of rectangular tanks, but I couldn't find it.  Here are some older posts which contain references to books/articles which may be of help.

thread1452-272642: Rectangular Tank Design
thread794-55086: Rectangular Tank Design
thread404-293556: Dynamics of a tank and
thread794-153709: Rectangular Tank Design.

Patricia Lougheed

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RE: Rectangular Tank

(OP)
I had all of those already ...Thanks.

If your are designing circular tanks..it's simple and you have many ways; a rectangular one, very few! Even less using Mohr's circle or the principal stress formulas.

Example S = 0.5 (Sy + Sx) ± [0.25(Sy – Sx)2 + Ss2]0.5

But in a boxed or closed rectangular tanks, where are the "obvious" stress points or area of interest!
big smile

JL

RE: Rectangular Tank

Is this for work or for school?

RE: Rectangular Tank

(OP)
Work...

JL

RE: Rectangular Tank

(OP)
What FEA software would be best suited for my needs?

JL

RE: Rectangular Tank

My two cents.....

My experience has been that, after bidding and designing a series of rectangular and clyndrical(API-650)tanks for a major US chemical company.....

You can be sure to pay about TWICE the cost for a rectangular tank than a circular tank. Stainless and other exotics only increase this ratio.

Furthermore, you have increased the cost of inpection and repair during the life of the tank.

Unless the tank is a special "one-of-a-kind" to perhaps fit into a certain area ( like.....ummmm....say a submarine) there is no reason to go with a rectangular design...... IMHO

Regards

   

RE: Rectangular Tank

(OP)
Client wants and needs a rectangular tank for space management.

JL

RE: Rectangular Tank

i wonder if i (and others ?) was mislead with your "FEA" comment ... have you done an FEA of this ?  are you asking what Sx, Sy, and Ss are (ie their values, since i'll assume you know they're stresses) ?  how to determine them for your tank ??

i guessing this isn't something that can be solved from scratch in a forum like this ... we don't know enough details.

roark has some data for rectangular plates.  his source is a paper written by Moody.  Google (seriously) "Moody Rectangular Plates" (truly, seriously) and you find the paper and a lot more detail than roark has.

RE: Rectangular Tank

i think the point of cronin's post is a rectangular tank is difficult (structurally inefficient) to design.  ok, your customer has a rectangular volume available .... do you have to fill it ?  rounding the sides as much as possible will be "better" (for efficient structure).

the reasons for keeping with a rectangular design are 1st the customer needs the volume, and 2nd other forms are too expensive (to make, to work with, ...).

simple flat sides will produce a heavy design.

RE: Rectangular Tank

(OP)
I know, I have been in "round tanks" for years

JL

RE: Rectangular Tank

ok, so you have to be rectangular ... what about my earlier post ?  FEA ? roark ??

RE: Rectangular Tank

(OP)
I am looking at some FEA programs. Most are expensive and I need one that can do detailed reports. I have to use Mohr's principal stresses as a reference as required by client.

JL

RE: Rectangular Tank

any will give you max and min principal stresses.

reports tend to be as detailed as you make them.  i don't think you'll get one to make a report at the press of a button ... if you can post it !.  I'd use hand calcs to verify your model.

RE: Rectangular Tank

I know that I'm a bit late, would you be interested designing your tank in accordance with AS 1692? It is specific to the rectangular storage tanks and extensively used in Australia, including exports...
Cheers,
gr2vessels

RE: Rectangular Tank

(OP)
I did the design by good old hand method...Thanks.

I would have liked to compare it to what FEA can produce though.

JL

RE: Rectangular Tank

Farm the FEA out to a consultant.  Require they provide details and come in to discuss with you.  You get an outside opinion, FEA ability that would take you years to obtain, and don't have to outlay for software.  Win, win.

ZCP
www.phoenix-engineer.com

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