Tubesheet calcs are extremely complicated and I would advise against trying to do them by hand.
If you do make the attempt, you must closely follow the rules of UHX, taking into account the type of tubesheet (floating, fixed, U-tube), expansion cases, mating bolt load, etc. Follow UHX very carefully.
abhimech1991, as others have stated there are number of different calculations for this. If the tubesheet is on a boiler it would be calculated using ASME Section I or IV. The ligaments, pitch, spacing, stay rods/bolts all have to be taken into account and can greatly change these equations. The only time I've attempted these by hand were to pass the National Board test, and wouldn't attempt them by hand unless you're extremely familiar and comfortable with these codes.
You wouldn't necessarily have to do these by hand, but what you would have to do is define the proper conditions under which to perform the calculations.
For example, shell & tube exchanger, MAWP for tubesheet, Part UHX. When calculating MAWP for one side, what is the condition for the other side? Is it at zero pressure? Operating pressure? Design pressure? Do you increment pressure for both sides at the same time, i.e. both sides at respective "MAWP"? Pressure only conditions? Pressure plus thermal expansion?
Who knows, I won't touch it. MAWP is design pressure. Period.
