Analysis of mechanical autofrettage in thick cylinders

Thick-walled cylindrical pressure vessels are commonly used in power, nuclear, chemical, armament and food industries as boilers, nuclear reactor vessels, high-pressure containers, and gun barrels. The autofrettage process can be applied to such cylindrical pressure vessels in order to induce favorable residual compressive stresses at the inner surface of cylindrical vessel to increase its load-bearing capacity. Both mechanical autofrettage and hydraulic autofrettage can be used for the purpose. This research work analyses the effect of mechanical autofrettage in terms of residual stresses to increase the load-bearing capacity of thick-walled pressure vessels. A mathematical model is developed including Bauschinger effect and the appropriate failure criteria. Numerical simulation of the mathematical model has been carried out using finite element method. The predicted results are validated using the available data. (authors)