Thermal and mechanical cyclic loading of thick spherical vessels made of transversely isotropic materials

The aim of this paper is to obtain the dependency of the ratcheting, reversed plasticity, or shakedown behavior of spherical vessels made of some anisotropic materials to the stress category of imposed cyclic loading. The Hill anisotropic yield criterion with the kinematic hardening theories of plasticity based on the Prager and Armstrong–Frederick models are used to predict the yield of the vessel and obtain the plastic strains. An iterative numerical method is used to simulate the cyclic loading behavior of the structure. The effect of mean and amplitude of the mechanical and thermal loads on cyclic behavior and ratcheting rate of the vessel is investigated respectively. The ratcheting rate for the vessels made of transversely isotropic material is evaluated for the various ratios of anisotropy.

► Cyclic loading analysis of anisotropic spheres is assessed.
► Using the Prager model results in ratcheting.
► Armstrong-Frederick model predicts ratcheting for load controlled cyclic loadings.
► The A-F model predicts ratcheting to a stabilized cycle for thermal loadings.