An analytical / numerical study on buckling behaviour of typical composite top hat stiffened panels

This paper deals with the buckling strength of typical ship stiffened panels built in fibreglass composite laminates. The results obtained applying analytical formulations based on equilibrium and potential energy equations are compared with the ones obtained by linearised eigenvalue analyses of rather detailed finite-element models. Analytical formulations consider an elementary panel only, accounting for the boundary effects of stiffeners surrounding its edges, while FE models fully describe the interactions among plate and stiffeners as a whole. A sensitivity analysis to highlight the most influencing parameters in the problem is also presented. So far no systematic scantling assessment of buckling behaviour of hull shell and deck panels seems to be recommended by classification societies’ rules for pleasure crafts made in composite materials. Thus, this paper aims at illustrating the application limits of analytical methods, natural candidates to become the basis of rule requirements. Difficulties in the evaluation of torsion behaviour of stiffeners and of corresponding buckling modes involving both the plate and the stiffeners are highlighted. Some concluding suggestions for rule scantling assessment formulations are eventually provided.