STUDIES OF THE GROWTH AND COLLAPSE OF VOIDS IN VISCOUS SOLIDS

The growth and collapse of isolated voids in power-law viscous matrix materials are investigated. The study is restricted to axisymmetric re mote stressing and to voids which are initially spheroidal with the ax is of symmetry of the voids coincident with the axis of symmetry of th e remote loading. Particular attention is given to the evolution of in itially spherical voids, but the effect of initial voidshape on subseq uent void evolution is also investigated. For linearly viscous matrix materials, the voids evolve through spheroidal shapes and the work of Budiansky et al. (1982) provides the desired information about the his tory of void shape and volume. For nonlinear matrix materials, the voi d evolution is idealized as proceeding through a sequence of spheroida l shapes, and the rate of deformation for a given instant is evaluated using a Ritz procedure developed by Lee and Mear (1992). The results of the study demonstrate that the history of void volume and voidshape is influenced significantly by the material nonlinearity, the remote stress state and the initial void aspect ratio.