Plastic limit loads for cylindrical shell intersections under combined loading

• This paper presents nonlinear two-dimensional FE analysis for shell intersections.
• Determining the plastic limit loads under combined loading is considered.
• Developed maximum criterion of rate of change of relative plastic work is employed.
• Plastic deformation mechanism in shell intersections is discussed.
• Results for generalized plastic limit load curves of branch intersection are presented.

In this research, applied methods of nonlinear analysis and results of determining the plastic limit loads for shell intersection configurations under combined internal pressure, in-plane moment and out-plane moment loadings are presented. The numerical analysis of shell intersections is performed using the finite element method, geometrically nonlinear shell theory in quadratic approximation and plasticity theory. For determining the load parameter of proportional combined loading, the developed maximum criterion of rate of change of relative plastic work is employed. The graphical results for model of cylindrical shell intersection under different two-parameter combined loadings (as generalized plastic limit load curves) and three-parameter combined loading (as generalized plastic limit load surface) are presented on the assumption that the internal pressure, in-plane moment and out-plane moment loads were applied in a proportional manner.