The primary mechanism of damage evolution of brittle materials in peridynamic theory is based on individual pair-wise bond strain. A critical value for bond strain is derived based on linear elastic fracture mechanic theory. It is a function of the horizon, the radius of non-locality of the material. The horizon must be larger than the material point spacing but not too large which would significantly slow the simulation. Typical sizes used for the horizon range between three and six times the material point spacing, if a constant multiple is used it could be said that the critical strain is a function of the model's material point grid resolution. This critical strain function ensures that the fracture toughness is independent of the horizon and grid resolution. This works well when modeled materials have pre-existing cracks. However, since the peridynamic fracture toughness manifests as a critical strain it imposes an artificial strength onto the modeled material that may not represent the real strength of the material. When the material strength is less than the model's critical strain certain flaw insertion methods can be used to capture the strength behavior. However, if the material strength is larger than the critical strain then the flaw size that represents that strength is too small to model. To address this discrepancy, multi-resolution models have been previously used, having differently sized horizons, such that the region that is expected to nucleate failure is represented correctly while the bulk material is modeled with a coarser grid and larger horizon. Such a multiscale approach could be designed from the beginning of the simulation or exhibit adaptive refinement during crack propagation. Such multiscale approaches add significant complexity to the simulation framework and fundamental model descriptions. This paper introduces a method that is able to decouple the model strength from the horizon and grid resolution by using a refinement overlay technique. This overlay is virtual and does not change the explicit material resolution as adaptive techniques do.

In glass research, the effect and influence of pre-deformation by thermal or chemical treatment is of great importance when configuring different mechanical properties or scratch resistance on the surface of glasses. In particular, such pre-deformation affects dynamic fracture or damage evolution when glass structures are under impact or collision conditions. Peridynamics provides a seamless approach for the simulation of dynamic damage evolution of the system under aggressive environments. Revising the pair interaction of each material point, the effect of pre-deformation is implemented, and the corresponding damage evolution can be simulated conveniently. Our approach is composed of two steps: first, a static solution is found via energy minimization with thermal boundary conditions in the peridynamic platform. Second, comparing the initial and the pre-deformed structures from the energy minimization, the effect of residual deformation, strengthening and reactive behaviour of brittle structures are seamlessly simulated. The developed methods are applied to the Prince Rupert’s drop and Bologna vial, which are classic examples of strengthened glasses. This study reports the first complete and successful simulation of dynamic behaviour of strengthened glasses, and a significant contribution in simulating residual stress behaviour in any material.