Residual stress analysis of swage autofrettaged gun barrel via finite element method

Abstract

Residual stress analysis of swage autofrettaged gun barrel is performed in this study via finite element (FE) method. The swage autofrettage technique is one of the modernized pre-stressing methods to enhance the load bearing capacity and fatigue life of all gun barrels. An oversized moving mandrel is forced inside the gun barrel, which deforms the material through physical interference. The process is analyzed by evaluating residual stresses using a commercially available software package. The deformation effects caused by the mandrel and the geometrical variation of the mandrel on the gun barrel are analyzed in this study. This field has been insufficiently researched, but the effect of pre-stressing on the barrel, and at the start and mid-length for the swaging process, is not well examined. Thus, further analysis is required. The variations and effectiveness of the designed pressure band model are shown to define the problem easily. Results are evaluated at mid-length using a fixed fringe width percentage (A defined percentage of gun barrel axial length). The desired effects are well validated through numerical investigation using FE analysis. This study reveals that the geometry should be designed very thoroughly to determine the after effects. If too many variations occur, then the initial force requirement is extremely high; otherwise, the desired swaging effect cannot be achieved.