Thermo-Mechanical Autofrettage Process of Spherical Vessel

In this analysis results of Elastic-plastic stress distributions in a spherical pressure vessel with ThermoMechanical loads are discussed. Results of study are obtained with Finite element (FE) analysis. A quarter of pressure vessel is considered and modeled with all realistic details. In addition to presenting the stress distribution of the pressure vessel, in this work the effects thermo-Mechanical autofrettage on different limit strength for spherical pressure vessels are investigated. The effect of changing the load and various geometric parameters is investigated. Consequently, it can be observed that to be the significant differences between the present thermo-Mechanical autofrettage and earlier (Mechanical autofrettage and Thermal autofrettage) method of autofrettage for the predictions of Elastic-plastic stress distributions of spherical pressure vessels. Some realistic examples are considered and results are obtained for the whole vessel by applying thermal load and mechanical load. The actual material curve is used for loading, unloading and residual stress behavior of spherical pressure vessel. Kinematic hardening material is considered and effect of Bauschinger effect factors are studied with thermo-mechanical load. Equivalent Von -Mises yield criteria is used for yield criteria. Behavior of elastic-perfectly plastic is also studied and compared. Influence of Thermo-Mechanical autofrettage over stress distribution and load bearing capacity of spherical vessel is examined. The question of whether Thermo-mechanical autofrettage gives more favorable residual compressive stress distribution and therefore extension of pressure vessel life is investigated in this analysis.