Residual ultimate strength analysis of stiffened panels exposed to fire

Studying the collapse mode of stiffened panel exposed to fire and calculating the residual ultimate strength of it accurately are all important for ship and marine structure designs and safety assessments. Considering the temperature-dependent material parameters, the method of thermal-elastic-plastic FE analysis with ideal elastoplastic model is used to study the collapse mode of stiffened panel under two different heating modes. The numerical results show that: The whole structure heats up faster and fails earlier when stiffener is heated; the collapse mode is beam-column-type collapse mode when plate is heated and a combination of overall collapse mode and local buckling mode of stiffener web when stiffener is heated. Beyond that, on the basis of the mechanical response of stiffened panel at different heating-up time, the ultimate strength of stiffened panel with initial imperfections under biaxial compression is analyzed. This innovation is that the thermal-elastic-plastic FE analysis method is used in study on ultimate strength with nonlinear finite element method.