For each miniature specimen tested, the energy at both 70% of maximum load and at maximum load were calculated based on the area under the curve. Fig. 6 shows the evolution of the fracture energy as a function of the pre-deformed biaxial level of each specimen for both notch lengths analyzed. As can be expected, the crack initiation energy needed for a 5 mm
notch length is greater than that needed for 5.4 mm for both cases (70% Pmax and Pmax).