<p>This study presents experimental and numerical analyses of joints and beams made of aluminum alloys 7075 T6 and D16 AT, joined using resistance spot welding (RSW). Joints corresponding to the sheet configurations applied in the beams were subjected to uniaxial tensile–shear tests, and local plastic strain fields were analyzed using digital image correlation (DIC). The structural response of the beams was evaluated through three-point bending tests. Numerical analyses were performed in ADINA and ANSYS using three dimensional solid models. The numerical models accounted for spatial variations in the mechanical properties of the RSW weld zones based on microhardness measurements and contour maps, enabling a realistic representation of differences between the base material (BM), the heat affected zone (HAZ), and the fusion zone (FZ). The results demonstrated good agreement between numerical predictions and experimental observations, allowing the identification of plastic strain localization and damage initiation mechanisms relevant to load-bearing assessment and the design of lightweight aluminum structures.</p>