Which tools can I use for buckling check of a structural element of a vessel?

Efficient buckling checks

Sesam, DNV GL's FEM software for offshore and ship structural analysis and design, includes several postprocessing tools for capacity (Ultimate Limit State) checking of stiffened and unstiffened panels, including buckling and yield checks.

The PULS buckling code is available as integrated in Nauticus Hull and Sesam’s GeniE, as well as standalone version and as spreadsheet.