Abstract: The creep behavior of a spherical vessel composed with the functionally graded material is derived under the internal and external pressure. The effects of elastic and creep graded distributions on the time-dependent stress/strain are systematically analyzed. The numerical results show that the elastic distribution only affects the stress development at the initial creep stage. When the stress reaches the steady state its magnitude is only related to the graded creep property distribution inside the vessel. However the variation of the creep strain is both determined by the graded creep property distribution and the graded elastic pattern. The different gradient distributions are further discussed to reduce the creep stress and strain along the wall thickness. The research work performed can be used to guide the structural and optimum design of functionally graded material spherical vessel.

Key words: Creep, Functionally graded material, Spherical vessel, Strain, Stress