spring washer for hold down case

Hi all,

I am working on 4 no. of heat exchanger package connected through bellow on shell side & direct pipe spool piece on tube side.
In order to qualify nozzle loads for direct pipe spool piece nozzle, we need to remove or provide the bolted arrangement of fixed & sliding saddle say with 3mm gap. Client agrees with our this proposal ..however, client ask to insert a spring washer in between the bolted fixed & sliding saddles of heat exchanger.

Now, how to model this in CAESAR II?

Also, what preload value we need to include for washer in CAESAR II?

Please provide your expert opinion on this

thanks

In my opinion you may model the spring washer set as EJ element with axial stiffness and all other stifnesses as rigis as it can be. No preload.

I would use also nozzle flexibilities and I would be careful in modeling as much as realistic the exchangers because with the saddles not loaded you will have the loads transfered on the nozzles.

Thanks Danb for your response.

you mean to say i need to model at saddle the below:

1.Rest + guide support at saddle bolting location
2.add a 50mm bellow spool with axial stiffness(i am considering 50mm as free length of spring washer)
3.-Y support with 50mm gap at the edge of the bellow point.

Is it ok?

Also, what value of axial stiffness can be considered if saddle bolt size is M16.

I think that you may use
1.Rest + guide support at saddle bolting location (CNODE is on the lower exchanger)
2.-Y support with stiffness (CNODE is on the lower exchanger)

The stiffness is to be determined from disk spring washer datasheet.

It is simpler than use the EJ.