Void coalescence in porous ductile solids containing two populations of cavities

Abstract

A model of coalescence by internal necking of primary voids is developed which accounts for the presence of a second population of cavities. The derivation is based on a limit-analysis of a cylindrical cell containing a mesoscopic void and subjected to boundary conditions describing the kinematics of coalescence. The second population is accounted locally in the matrix surrounding the mesoscopic void through the microscopic potential of Michel and Suquet (1992) for spherical voids. The macroscopic criterion obtained is assessed through comparison of its predictions with the results of micromechanical finite element simulations on the same cell. A good agreement between model predictions and numerical results is found on the limit-load promoting coalescence.

Numerical prediction of the effect of irradiation on the Charpy Upper Shelf Energy of Reactor Pressure Vessel steels

“…However, void nucleation could also affect indirectly void growth and coalescence through the parameters q 1 , q 2 , q χ by changing microscopic scale hardening behavior. Typically, void nucleation from carbides (below 1µm) in between voids nucleated from MnS inclusions (above few µm) is expected to favor void coalescence, as shown in [58]. This may provide a rationale for the evolution of the parameter q χ with irradiation, but experimental data are required to support this hypothesis.…”