Rectangular Tank

[jlarocque]

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

 

[vpl]

Do you have a question?

Patricia Lougheed

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Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

 

[jlarocque]

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

JL

 

[rb1957]

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?

 

[jlarocque]

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

JL

 

[msquared48]

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

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

 

[vpl]

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
thread794-55086
thread404-293556 and
thread794-153709.

Patricia Lougheed

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Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

 

[jlarocque]

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!
:-D

JL

 

[TGS4]

Is this for work or for school?

 

[jlarocque]

Work...

JL

 

[dvd]

You can't go wrong with a copy of "Design of Weldments" by Omer Blodgett. There is a section on designing tanks.

https://ssl.lincolnelectric.com/foundation/item.asp?prodnum=DW&PID=16

 

[jlarocque]

What FEA software would be best suited for my needs?

JL

 

[MJCronin]

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

 

[jlarocque]

Client wants and needs a rectangular tank for space management.

JL

 

[rb1957]

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.

 

[rb1957]

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.

 

[jlarocque]

I know, I have been in "round tanks" for years

JL

 

[rb1957]

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

 

[jlarocque]

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

 

[rb1957]

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.