Issue 78

C. Popa et alii, Fracture and Structural Integrity, 78 (2026) 118-128; DOI: 10.3221/IGF-ESIS.78.07

To extract stress and deformation results in the region of interest with improved consistency, a local coordinate system was defined and used to create a construction-geometry surface. This surface facilitated the evaluation of field quantities (e.g., total displacement, Von Mises equivalent stress, maximum shear stress and maximum normal stress on the loading direction) in a prescribed location. Fig. 3 shows the results-extraction surface positioned between the cut regions.

Figure 3: Construction geometry surface between the pre-cracks.

A total of 145 numerical simulations were conducted using different combinations of design parameters. The resulting response values are summarized in Fig. 4, where the outcomes are visualized using heatmap plots for various values of parameter A. The blue marker denotes the optimal configuration, identified by the highest value of the objective metric, defined as the ratio between maximum shear stress to maximum normal stress along the loading direction, S= / . This ratio is used as an objective function because it quantifies the degree to which the stress state approaches pure shear. A higher S value indicates a reduced influence of normal stress, which is essential for obtaining reliable shear strength measurements. The results indicate that a 60° notch orientation provides the most favorable response across all distances investigated. In addition, the 3D plot in Fig. 5 summarizes the full parameter space and highlights the optimal configuration. The best performing case corresponds to a A= 6 mm distance, B=1 mm radius and C = 60° angle

121