Buckling of Aluminum Silo

[farzam]

Dear All,
Our client has problem with buckling of a aluminum vertical silo(ID=3500mm, L=10000mm, thk.=4mm)first i tried by using ASME Div1,considering ring but it did not work.Actually Im not sure ASME applicable for silo or not?and if it is, so what is the solution?

Thanks in Advance

 

[MJCronin]

farzam....

Amy pictures ? Where, on the silo, was the failure ?

What is the material ?

Did the silo buckle during an event (wind, seismic or during discharge or...what ?)

Was the silo designed for "mass-flow" conditions ?

More info would help....

 

[JStephen]

Silo design can be an involved issue.

The most likely cause of buckling would be eccentric loading or unloading of the silo. ASME is not really set up to handle this kind of stress in a shell.

Buckling could be due to vertical drag (develops compressive stress in the shell) or due to internal vacuum/ external pressure. The compressive stress and external pressure approaches of ASME would work for this type of loading, if the shell material is included in ASME.

 

[vesselfab]

Could also be the skirt below the cone bottom. Some folks dont put that big vertical load on the skirt and just go with the same thickness of shell. Bad mistake.

 

[farzam]

Dear MJCronin,
Actually the silo has been buckled first time 2 years ago during unloading on surface of silo.the Client installed a structure(2rings with some pipe installed between thease 2rings)rings didnot weld to silo.
Now again the problem happened for the other location on the silo lower than the first ring. they do not know the reason.
material of silo is Aluminum,AlMg3.

Thanks in Advance

 

[nackra]

what type failure?
buckle "inward" or "outward"?
could be vent is too small if unloading rate creates "vacuum" in silo