Fixed tubesheet with hub welded to shell

[b5quaj]

For fixed tubesheet with hub welded to shell(Refer to Fig. UW-13.3),
If Allowable stress of tubesheet is lower than allowable stress of shell,
Shall Hub end thickness be checked as per UG-27 consider hub as cylindrical shell Or May hub end thickness be equal to shell thickness?

Please reply from your experience and knowledge.
Please send me information to solve this problem?
b5quaj@hotmail.com

 

[deanc]

See UG-34,Appendix 2 for the hub. See Appendix AA for the tubesheet. Talk to your AI.

 

[b5quaj]

As an example,

I determined fixed tubesheet thickness as per TEMA.
And This tubesheet has hub to be welded to shell.
But allowable stress of tubesheet is lower than allowable stress of shell.

How should I determine hub thickness to be butt-welded to shell? by UG-27 or by shell thickness?

Is it correct to consider hub of tubesheet as cylindrical shell?

 

[prex]

I think that you should consider the hub as a cylinder and calculate it per UG-27.
Of course this is not really necessary from a strength point of view, but as I don't see this case treated by code formulae, I think you have no choice.

prex

http://www.xcalcs.com

Online tools for structural design

 

[deanc]

IMO-There are more things a work here. See Appendix AA-2.5

 

[prex]

deanc,
Point AA-2.5 deals with bending + membrane stresses in the longitudinal direction only, and is therefore unrelevant to circumferential stress checking.
Of course the check of circumferential membrane stress due to pressure only is a prerequisite to any other check: hence I maintain my point.

prex

http://www.xcalcs.com

Online tools for structural design

 

[deanc]

prex:My concern is that there is more going on then meets the eye(been doing this for too long,suspicious). Down and dirty I agree with you. Think this design needs more attention.