Ultimate bearing capacity analysis of reinforced butt joints of large marine composite structures: Numerical optimization and experimental verification

• The processing technology and optimization measures of reinforced butt joint are put forward. • The simulation method of progressive failure of complex composite structures is improved and renewed. • The ultimate bearing capacity of reinforced butt joints are predicted and verified. With the increasing use of composite materials in large ship structures, bonded joints have become a crucial component of hull connection structures. This paper investigates the ultimate load-bearing capacity and failure mechanisms of large adhesive joints in stiffened composite sandwich structures. Full-scale experiments and numerical simulations are conducted to analyze the ultimate strength, strain distribution, and displacement behavior of the joints under various loading conditions. An improved progressive damage analysis method, combined with a cohesive zone model, is proposed to accurately predict the failure process and load-bearing capacity of the bonded joints at each stage. The impact of key factors, such as the overlapping width and reinforcement thickness, on the structure's bearing capacity is quantitatively analyzed. The findings offer valuable insights for optimizing the design and improving the efficiency of large-scale composite adhesive joints in marine applications.