Coating Breakdown Analysis of Steel Plates in Marine Structures
The objective of the present study is to analyse the coating breakdown of steel plates in marine structures, subjected to uniaxial in plane compression. A finite element model is developed and validated in ANSYS. The behaviour of the coated steel plate, with an initial imperfection and a macro delamination in the interface, is studied based on the eigenvalue buckling and nonlinear strength analysis. The compressive loads acting on the plate, in addition to the initial imperfections caused by the inadequate steel surface preparation and/or poor coating application, leads to the local buckling of the coating layer. As the load increases the buckled region increases reaching the critical size, when the coating layer starts to delaminate. Based on the exponential form of the cohesive zone model, a zero thickness interface element, to model the adhesion between plate and coating layer, is employed. When the stress in these elements exceeds the critical one, the stress field is redistributed, resulting in the element deformation and separation/delamination across the interface. The influence of the delamination length, coating thickness, mechanical and interface properties on the buckling and post buckling behaviour of the steel plate coating are also studied. Based on these results, a coating failure assessment diagram for the macro delamination diameters is created.