Abstract: A substrate having inner and outer major surfaces, a plurality of edge surfaces, and a plurality of corner surfaces; and at least one of: (i) a coating applied over a limited area of the outer major surface of the substrate to produce a composite structure, (ii) an intermediate layer applied to the inner major surface of the substrate, and (iii) an elongate discontinuity disposed at one or more corners of the substrate, each of which operates to reduce catastrophic failures in the substrate resulting from a dynamic sharp impact to the outer major surface of the substrate.