THE BENDING-BUCKLING COUPLED MECHANICAL MODEL FOR WRINKLING BEHAVIOR IN MARINE ANTI-CORROSION COATINGS

Marine anti-corrosion coatings are subjected to extreme marine environments, where wrinkling is one of the primary forms of damage and failure. Understanding the wrinkling failure mechanism of anti-corrosion coatings is helpful for optimizing their structural design and extending their service life. Based on the chemo-mechanical coupling environment of marine anti-corrosion coatings, and considering the precise geometric relationship of large deformation associated with coating wrinkling failure, this paper establishes a bending-buckling coupled mechanical model, and employs perturbation methods to solve the nonlinear straight-sided buckling and post-buckling problems of the coating. The study analyzes the functional relationship between the buckling load, induced by the diffusion of corrosive substances, and the maximum deflection of the coating, under transverse bending load opposite to the deflection direction. The effects of hydrostatic pressure and the coating's aspect ratio on post-buckling behavior are discussed. The distribution laws of axial force, deflection, and cross-sectional rotation angle of the wrinkled coating are precisely determined. Finally, a comparative analysis is conducted with theoretical predictions based on the F?ppl-von Kármán (FvK) assumptions. The results reveal that as the buckling load increases, the theoretical model based on the FvK assumptions gradually underestimates the nonlinear effects of geometric large deformation of the coating, resulting in an underestimation of the maximum deflection.