Mechanical APDL can account for irradiation-induced swelling (accessed via TB,SWELL). Swelling is defined as a material enlarging volumetrically in the presence of neutron flux. The amount of swelling can also be a function of temperature. The material is assumed to be isotropic and the basic solution technique used is the initial stress method.

For a solid element, the swelling strain vector is simply:

(4–272)

It is seen that the swelling strains are handled in a manner totally analogous to temperature strains in an isotropic medium and that shearing strains are not used.

For more information, see Swelling in the Material Reference.