<p>In this study, they investigated the effect of interfacial bond strength on the mechanical properties and fracture mechanisms of aluminum/steel (Al/Steel) composite plates using both finite element simulations and experimental methods. Numerical calculations were performed by progressive failure analysis, considering the failure initiation criteria under failure evolution based on the energy criterion. Different interface bond strengths were achieved by employing wire brush and blue oxidized surface treatments, allowed for a detailed analysis of stress distribution, failure patterns, and fracture mechanisms of composite plates under varying bond strengths. The results indicate that a higher bonding strength of the composite plate leads to a more uniform stress distribution at the gauge length section during the tensile test, thereby eliminating stress concentration and increasing plastic elongation. Additionally, specimens exhibit bending toward the Steel side in width but toward the aluminum side in the drawing direction, leading to a significant x-shaped highly strained zones in the gauge distance segment and a characteristic 45° beveled angle in tensile fractures. A key observation is that increased interfacial bonding strength enhanced plastic ductility and reduced the delamination distance along the tensile direction. The close correlation between the simulation results and experimental data confirms the validity and reliability of the finite element approach in predicting delamination failure of composite plates.</p>