Numerical investigation of residual stress formation during swage autofrettage process

Authors : Doğan Baran, Osman Bican, Yahya Doğu

Pages : 939-955

Doi:10.5505/pajes.2025.86727

View : 70 | Download : 146

Publication Date : 2025-11-13

Article Type : Research Paper

Abstract :Autofrettage is the process of developing residual stress through the wall thickness of the cylinder to increase the pressure carrying capacity and fatigue life of thick-walled cylinders. Although there are many techniques in practice, swage and hydraulic autofrettage processes have been mostly used in heavy gun barrel production process. In this study, the stresses developed at the end of the swage autofrettage process on a heavy gun barrel are numerically calculated by using an FEA (Finite Element Analysis) software. In FEA, a two-dimensional (2D) axisymmetric model has been used. The Von Mises stress under working pressure for non-autofrettaged barrel is calculated as 1350.3 MPa. The Von Mises equivalent stress for the autofrettaged barrel is 1122.3 MPa at 63% barrel thickness. It is seen that this stress is below the barrel yield strength of 1195 MPa. As a result, there is 16.88% reduction of Von Mises equivalent stress for autofrettaged barrel under the working pressure. In addition, the pushing force generated during the mechanical autofrettage process has been calculated numerically and experimentally. The pushing force is calculated with FEA software as 135.58T while it is empirically measured as about 142T. When the numerical and experimental results are compared, it is seen that there is an error of 4.52% between the two results. It is possible to say that this percentage error is quite reasonable. Finally, it is possible to say that the numerical study is quite successful in terms of accurately reflecting the real-world conditions.
Keywords : Mekanik Otofretaj, Kalıntı Gerilme, Sonlu Elemanlar Analizi (SEA), Sürtünme

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