Damage and failure mechanism of sapphire under ballistic loading based on a modified bond‐based peridynamic model

To investigate the dynamic mechanical behaviors of c ‐plane and a ‐plane sapphire, a novel anisotropic constitutive model and fracture criterion are constructed on the basis of bond‐based peridynamics (BB‐PD) theory. And the concept of strain is introduced in the framework of BB‐PD. After that, the simulations of a ‐ and c ‐planes of sapphire under spherical and cylindrical impact are conducted. In addition to capturing the distribution of strain and damage, the histories of various fracture types such as the primary fracture front and cracks are monitored for quantitative analysis. The numerical predictions are shown to agree well with previous experimental results, and further reveal the damage and failure mechanisms of sapphire. The different forms of contact between the projectile and the target strongly influence the stress waves generated and energy transferred ultimately affecting the damage development process. The crystal orientation dominates the appearance of anisotropic crack modes. Crack bending and deflection, as well as spalling‐like fracture, are associated with wave reflection and intersection. Moreover, an in‐depth examination of the observed wave splitting phenomenon is performed.