Effect of Pressure Ratio on Tangential/Axial Stress in Thick Spherical Vessels

The study describes the effect of varying pressure ratio on tangential/axial stress in thick walled spherical vessels under uniform temperature field. The spherical vessel is made of functionally graded material and plain strain condition was assumed. The creep behaviour of material is governed by threshold stress based creep law. The study reveals that for assumed pressure ratio the threshold stress decreases linearly with maximum value at inner radius and minimum value at outer radius of spherical vessel. On the other hand the creep parameter M increases from inner radius to outer radius. The tangential/axial stress which is dependent upon creep parameters remains compressive at inner radius, however, the value become tensile for pressure ratio 3, 4 and 5.