TEMA FSE FEA RCB 8

[tabbymulla]

Hello everyone,

I was trying to perform a finite element analysis of a heat exchanger expansion joint on ANSYS following RCB 8 of TEMA. I modeled it according to Figure RCB 8.42, applied boundary conditions as per RCB 8.41 and determined spring rate. Now to determine deflection to be applied, I need a parameter "Axial membrane stress (S)" as mentioned in RCB-8.42 which is to be computer but how, that I don't know and is not explained. Can anybody kindly guide me? Plz

Regards,

Tabby Mulla

 

[DSB123]

tabbymulla,
Not having read the excerpts of TEMA you quote I would have thought that the FEA model under deflection/loading would yield the Axial Membrane Stress in the unit which you can compare with the materials allowable stress.

 

[tabbymulla]

@DSB123,

Well there is this procedure in TEMA RCB 8.

First an FEA is performed in order to determine displacement for spring rate calculation.
Then, this spring rate is used to calculate the induced axial displacement which is used in second FEA to determine stresses.

But to calculate induced axial displacement, a mathematical relation is provided in TEMA RCB 8.42 which also require "Axial membrane stress (S)" which TEMA specified that it has to be computed but does not indicate how nor does refer anywhere.