Tube sheet design by code formulas - ramification of plasticity at the tube sheet shell joint

摘要

The ASME Special Working Group on Heat Exchange Equipment is currently developing rules for the design of heat exchanger tubesheets having different edge supports. The tubesheets can be in P-tube exchangers, fixed tubesheet exchangers, or floating heat exchangers. One problem area which is being investigated involves the effect of local plasticity at the tubesheet-barrel junction, and how to account for such action while using a design method which relies entirely on elasticaction of the plate-like tubesheet and the shell-like barrel. In this paper, we use finite element analysis to develop solutions when plastic action is permitted to occur in the heat exchanger barrel. We compare the finite element results withthe proposed ASME method and suggest approximations to the ASNE elastic method that provides for the effect of local plasticity.