Finite element analysis of mechanical behavior of bellows with a wall-through crack

The use of bellows expansion joints in the piping of a liquid metal fast breeder reactor is expected because of their displacement absorbing capability and space saving advantage. However, their reliability in a high temperature condition as pressure boundary is yet to be confirmed. The authors perform a series of linear elastic finite element stress analyses on a one convolution bellows with a circumferential through-wall crack of a variable length at either the root apex or the crown apex. The bellows is either subjected to an internal pressure or prescribed axial displacement at the end. The effect of parameters on the mechanical behavior of the bellows is discussed with the results. Stress intensity factors are also evaluated from the obtained displacements and stresses using the extrapolation method. (author)