<p>Problems in structural dynamics that involve rapid evolution of the material at multiple scales of length and time are challenging to solve numerically. One such problem is that of a structure un- dergoing fracture, where the material in the vicinity of a crack front may experience high stresses and strains while the remainder of the structure may be unaffected by it. Usually, such problems are solved using numerical methods based on a finite element discretization in space and a finite difference time-stepping scheme to capture dynamic response. Regions of interest within the struc- ture, where high transients are expected, are usually modeled with a fine discretization in space and time for better accuracy. In other regions of the model where the response does not change rapidly, a coarser discretization suffices and helps keep the computational cost down. This variation in spatial and temporal discretization is achieved through domain decomposition and multi-time-step coupling methods which allow the use of different levels of mesh discretization and time-steps in different regions of the mesh.</p>