Finite Element Modeling and Analysis for Creep Buckling of a Cylindrical Shell Subjected External Lateral Pressure with Local Wall Thinning

The corrosion, erosion, or worn defects on cylindrical shells often lead to localized wall thinning. The influence of the local wall-thinning defects on the creep buckling behavior of the cylindrical shells serving in high-temperature environments with high pressure is studied. A finite element model is developed for a Zircaloy cylindrical shell with two kinds of geometrical imperfections, including initial ovality and local wall thinning, which are the representations of the global and local geometric imperfections, respectively. Their influence on the creep buckling modes and the critical buckling time is investigated through the creep buckling analysis. It is revealed that the buckling modes are dominated by the ovality deformation in a wide range of defect widths, whether the initial ovality appears or not. The local thinning defects significantly reduce the critical buckling time of the cylindrical shells with initial ovality, where a 30% reduction was observed even with a small local defect, highlighting the need for careful consideration in practical applications.