Many manufacturing processes utilize sheared bulk materials as feedstock. However, shear-induced defects can significantly compromise the final product quality ultimately affecting its functionality. To address this issue, the present study conducts a parametric analysis of the failure behavior of sheared aluminum bulk, focusing on the interplay between process parameters and material response. The shearing process is first examined to determine the prevailing stress states, which include compression, tension, and shear. A finite element model incorporating thermo-mechanical coupling is employed to simulate these stress conditions accurately. For modeling ductile damage, the Johnson-Cook constitutive model is adopted, along with the stress triaxiality parameter, to capture material failure under several loading scenarios. Additionally, this study evaluates the influence of specimen geometry on the outcomes of mechanical characterization tests. Variations in geometry can lead to discrepancies in stress distribution and failure modes, thereby affecting the reliability of experimental data. By systematically analyzing these effects, the study aims to optimize test configurations for more accurate material characterization. The findings provide critical insights into the shear-induced damage mechanisms in aluminum, facilitating improved process design and quality control in industrial applications. This research contributes to a deeper understanding of material behavior under shear-dominated loading conditions, supporting advancements in precision manufacturing.