Effect of residual stress on stress intensity factors of inner barrel bore cracks

DOI:	10.11809/bqzbgcxb2023.02.001
Keywords:	autofrettaged barrel; residual stress; XFEM; crack; stress intensity factor
Abstract:	Autofrettage creates plastic deformation of the inner bore of a barrel by applying self tightening pressure so as to produce residual stress and increase the strength of the barrel. It is also an effective method to improve the service life of the barrel. In order to study the influence of residual stress on inner barrel bore cracks, this paper establishes a finite element model of barrel expansion with residual stress. The intensity factors of inner bore surface cracks under the action of residual stress field of the barrel with different autofrettage are calculated, and the effects of self tightening residual stress and crack depth on the magnitude of crack stress intensity factors are analyzed. At the same time, under the condition of residual stress release after continuous shooting, the variation law of residual stress of autofrettage barrels and the effect of surface thermal stress on crack stress intensity factors are calculated. The results show that the autofrettaged residual stress can effectively inhibit the crack propagation of the barrel and improve the fatigue life, and its inhibition effect is positively related to the magnitude of the residual stress. After the barrel is shot, under the action of thermal load, the residual stress on the surface layer changes from compressive stress to tensile stress, and the values of tangential residual stress in other areas also decrease accordingly. The residual tensile stress makes the surface layer of the barrel easier to crack.
Published:	2023-02-28
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