There are several factors that can contribute to a weaker critical fracture energy in a material, including its microstructure, chemical composition, and mechanical properties. For example, materials with a more disordered or amorphous microstructure tend to have a weaker critical fracture energy than those with a more ordered or crystalline microstructure. Similarly, materials with a lower strength or toughness tend to have a weaker critical fracture energy than those with a higher strength or toughness. However, as this study takes place at the continuum scale, with no consideration for microstructure or chemical composition, we can target this lower critical fracture energy to the mechanical properties being effected.