Comparison of Finite Element Analysis and Classification Society Standards for Buckling and Ultimate Strength Evaluation of Flat and Curved Plates

_ This study presents a comprehensive comparative investigation of the buckling and ultimate strength behavior of flat and curved plates subjected to longitudinal compression, utilizing nonlinear finite element analysis (FEA) with NASTRAN, ABAQUS, and ANSYS and benchmarking the results against the established rules of major classification societies including American Bureau of Shipping (ABS), Bureau Veritas (BV), Det Norske Veritas (DNV), and Germanischer Lloyd (GL). The parametric analysis was conducted on plates with an aspect ratio of 3.0, thicknesses ranging from 10 to 25 mm, widths from 800 to 1000 mm, and curvature radii from 3000 to 10;000 mm (corresponding to flank angles of 5°–45°), encompassing the typical geometric configurations found in large LNG carrier hull structures. The findings reveal that for flat plates, FEA predictions demonstrate excellent correlation with classification society rules, with mean ratios of FEA to rule-based strengths between .988 and 1.036, coefficients of variation below 5%, and coefficients of determination R2 exceeding .985, confirming the adequacy of existing empirical methods for flat plate assessment. Keywords ship structure; buckling; regulations and standards; longitudinal strength; structural analysis