Spreading of Plastic Zones in Functionally Graded Spherical Tanks Subjected to Internal Pressure and Temperature Gradient Combinations

Thermo-Elasto-Plastic analyses of thick-walled spherical tanks made of functionally graded materials (FGM) are investigated analytically. These tanks are subjected to positive or negative temperature gradient and internal pressure loadings, separately or simultaneously. The power law modeling has been used for considering the throughthickness variation of mechanical properties. von Mises yield criterion and Elastic-Perfectly-Plastic assumptions are used for describing the material behavior in plastic zones. The patterns of plastic zones spreading for various combinations of internal pressure and positive or negative temperature gradient are investigated. Conducting numerical exercises for similar problems in ABAQUS software shows the excellent agreement with the analytical solutions. FG sphere subjected to internal pressure and negative temperature gradient yields at a lower pressure than the FG sphere subjected to internal pressure. Internal pressure and negative temperature gradient combination is the most critical loading combination. Moreover, the results show that the capacity of FG spherical tank subjected to internal pressure is increased by applying a positive temperature gradient.