A numerical investigation of tripping

The twin aims of the present study are to investigate numerically the characteristics of tripping failure of flat-bar stiffened panels subject to uniaxial compressive loads and also to study the accuracy of two available design formulations. A special-purpose nonlinear finite element method capable of efficiently analyzing the elasto-plastic large deflection behavior of stiffened panels is developed and used in the study. A benefit of the application of the nonlinear finite element method is that it makes possible a rigorous accounting of the interacting effects of stiffener tripping and plating collapse and also the inclusion of the influence of elasto-plastic rotational restraint at the plate-stiffener intersection prior to and during failure. A parametric series of elasto-plastic large deflection analyses for stiffened panels with flat-bar type of stiffeners under uniaxial compressive loads are carried out varying member proportions and structural parameters. Based on the computed results, a basic investigation of tripping behavior of flat-bars is made, and the accuracy of design formulations is studied. The calculations and comparisons of this paper are for flat-bar stiffened panels under uniaxial compression, but the special-purpose finite element method implemented is considerably more general.