Geometric effects on shakedown and ratchetting of axisymmetric cylindrical shells subjected to variable thermal loading

This paper presents results obtained from numerical simulations of the responses of an elastic-plastic thin cylindrical shell to fluctuating axisymmetric temperature in the presence of uniform axial stresses. The engineering situation considered has practical importance in nuclear reactors and has been the subject of a number of earlier studies. The main purpose is to assess quantitatively the influence of geometry changes, primarily due to plastic yielding, on shakedown and ratchetting (incremental collapse) phenomena. In particular, these phenomena are investigated with respect to both the stabilizing effects of tensile primary stresses on them, and their strong interference with elastoplastic buckling. The systematic evolutive analyses presented herein are also intended to critically assess the validity of earlier results (mainly condensed in the so-called Brussels diagrams) which have been established by simplified methods of shakedown based on the small deformation (no geometric effects) hypothesis.