This study investigates the resistance spot welding (RSW) of two different steels, AISI 1005 and AISI 304L, using both experiments and computer simulations. Researchers used a Taguchi L16 design to test how welding current, squeeze time, welding time, and hold time affect tensile-shear strength (TSF). The best welding setup reached a TSF of 78.86 MPa, while the lowest settings gave 44.31 MPa. Simulations in COMSOL Multiphysics modeled the thermal, electrical, and mechanical behavior of the welds. The predicted TSF values matched the experiments closely, with less than 5% difference. Free-vibration modal analysis was also done for cantilever and fixed-fixed setups. The experimental and simulated eigenfrequencies were similar, with errors within ±3%, supporting the accuracy of the model. These results show that choosing the right RSW parameters can greatly improve both the strength and stiffness of AISI 1005/AISI 304L joints.