In this paper we analyze the behavior of hysteresis curves of CK20 alloy steel cylindrical shells under various types of axial cyclic loadings. Due to occurrence of local buckling in sections which are under compressive loads and also due to decrease of cross section in regions which are under tensile loads, hysteresis curves show different behavior in compression and tension regions over cyclic loadings. Under displacement-control loading condition, by increasing of displacement amplitude we can see softening behavior in specimens. Softening rate is higher in regions which are under compressive loading due to creation of local buckling. Under axial asymmetric force-control loading condition, we can see ratcheting behavior in shells and by increasing of displacement amplitude, ratcheting rate is increased and the shell is failed over few cycles.

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