Pressure limits of thick-walled cylinders

Abstract

The effect of autofrettage on thick-walled cylinders, operating under high internal pressure, has become a significant area of development, both in research and practice. In optimal design of thick-walled cylinders, there are two main objectives to be achieved: increasing its strength-weight ratio and extending its fatigue life. This can be achieved by generating a residual stress field in the cylinder wall prior to use. Both analytical and numerical techniques have been used for the investigation of the effects of residual stresses on the load-carrying capacity. The scope of the current paper includes application of ABAQUS finite element code to the direct problem of finding thick-walled cylinder autofrettage solutions. The results reveal three scenarios in the design of thick-walled cylinders. For maximum load carrying capacity, non-autofrettage is suitable when, in service, the whole wall thickness will be yielded. Full autofrettage is suitable when, during subsequent operation, yielding is limited at the inner surface. Optimum autofrettage of the cylinder is suitable if a minimum equivalent stress is to be achieved. The analytical solutions were compared to numerical results and a very good correlation in form and magnitude was obtained.