Design of Legs Welded Directly to Conical Shaped Bottoms

mwhytlaw
(not verified)
Posted in: , on 10. Oct. 2002 - 01:38

"Hi

My name is Michael Whytlaw and I have just begun working as a Mechanical Engineer for an Engineering Fabrication company that manufacture wine tanks and silos.

I have been asked to design a wine tank that requires the legs to be welded directly to the conical shaped bottom part of the tank.

So far I have not been able to find any literature on the design of legs that are welded directly to the cone at the bottom.

Is there any literature available on this?

If not, does anyone know of an analytical approach that can be used to design the legs to connect to the tank in this manner?

Michael Whytlaw

mwhytlaw2002@yahoo.com.au"

Robert Sander
(not verified)

Re: Design Of Legs Welded Directly To Conical Shaped Bottoms

Posted on 14. Oct. 2002 - 04:12

I do not think this can be done without considerable modification of the inside of the tank. It would help to know the size of the tank.

As you might imagine, putting legs on the cone directly would introduce forces on the cone for which the cone was not designed. I think you would have to put a stiffener on the cone to distribute the load around the cone. The ring would have to be conical shaped to match the cone it was installed on.

I do not see this as a very good design. I think the reason you don't find design guidance in the literature is that it is seldom done. It is not clear from your question why you must do this. It would seem to me that a new vessel designed to meet your constraints would do better than what you propose.

Randall Carroll - River Consulting, USA
(not verified)

Re: Design Of Legs Welded Directly To Conical Shaped Bottoms

Posted on 5. Dec. 2002 - 03:12

If your requirement is to have the supporting legs of the tank inside of the footprint of the tank you might want to consider extending the side wall of the tank below the cone to cylinder junction creating a skirt. Inside this skirt you may attach chord plates which may be used to transfer the load to the supporting structure.

mwhytlaw
(not verified)

Reply To Previous Posts

Posted on 9. Dec. 2002 - 10:39

As I have learnt over the last couple of months, the legs on most silos and tanks are connected to the side of the tank, not the bottom cone.

The tanks are used for storing wine.

They have a diameter of about 2000mm, a height of about 3.0m and a storage capacity of 10,000 litres.

The angle on the bottom cone is normally 15 to 20 degrees.

The material on the bottom is cone is normally made from 2.5mm thick stainless steel.

A number of tanks imported from Italy have been made with the legs (normally folded 2.5mm thick S/S in the shape of a hollow rectangular box) welded to the cone.

Due to "competition" leading this design approach, most of our wine producer customers in Australia insist on us making the legs the same as those imported from Italy.

We have had to use Finte Element Analysis to assess the loads on the bottom cone and the legs.

We have successfully built many tanks in this manner, but I do not have an alternative way to FEA of assessing the strength of the legs and the conical bottom.

I am hopeful there may be some literature in existence that I am not aware of that provides a conventional approach to calculating the stresses in the legs and the conical bottom.



Michael Whytlaw

ring that goes around the base of the tankdesigned with , tanks etc.