calculating the combined ring-shell section I'

[monk1999]

Hi,


When you try to compare the combined ring-shell sections, the required moment of inertia is I's formula which is straight forward. But when calculating the combined ring-shell section I' - what is the cross sectional area of the shell section contributing to the moment of inertia? Is it the nominal shell thickness (ts) * 1.10*sqrt(Do*ts) or ts minus the thickness required to withstand external pressure * 1.1*sqrt(Do*ts)?


Regards,
Monk

 

[SnTMan]

Might be useful if you would reveal the Code and Part you are working to.

Regards,

Mike



The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[monk1999]

Section UG-29 of BPVC Sect. VIII Div 1

Regards,
Monk

 

[SnTMan]

Oh, OK, under the nomenclature, I', ts is nominal thickness of the shell. This would normally be understood as with any corrosion allowance deducted.

Note that I' is computed on the composite ring-shell section per the parallel axis theorem with the width of shell section contributing as noted in the definition of I'.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand