Dynamic modeling of solids with discontinuities

Large solid material masses inevitably contain discontinuities. In many cases they occur in one or several parallel sets with individual discontinuities spaced at regular intervals. The numerical treatment of the combined effect of motion across discontinuities and deformation of the intervening intact blocks poses a formidable challenge. Two general complementary approaches are considered for stress wave interaction: explicit, in which the motions across the discontinuities and the deformation within the blocks are represented separately; and implicit, wherein a single effective medium is defined so as to deform on average like an assemblage of blocks and discontinuities. The implicit composite model admits arbitrary constitutive behavior in both the intact blocks and discontinuities, and by enforcing internal compatibility and stress equilibrium derives a super-element representing the combined anistropic behavior due to both discontinuities and continuous blocks, in close agreement with the explicit model.