Self Tight Thick Outer Wall Of The Cylinder With The Carrying Capacity Of The Remaining Cracks

Autofrettage thick-walled cylinders are widely used in nuclear power, petroleum, transportation, chemical, military and other various industries and fields. Their security issues have been particularly important. Once the explosion or leakage accident occurred, safety of the lives and property of humans will have huge losses. In most cases, autofrettage thick-walled cylinder accident was caused by cracks or the expansion of other defects. Therefore, the study of the remaining carrying capacity of thick-walled cylinder with cracks has important engineering significance.Based on the elastic-plastic theory and the linear elastic fracture mechanics, Bauschinger effect of thick-wall cylinder material was considered as the function of equivalent plastic strain, the formulas of residual stress in autofrettage thick-walled cylinder were derived under the material of bilinear hardening model. The equation of stress intensity factors of internally pressurized thick-walled cylinder was used as the reference case, the formulas of stress intensity factor were derived through the weight function approach; Finally, by the calculation examples, the regularities of the residual stress and stress intensity factor of thick-walled cylinder with single crack or double crack were studied, the influence of crack depth and internal pressure and the extent of autofrettage to residual bearing capacity of thick-walled cylinder was analyzed.Conclusion of this paper has certain reference significance to the study of autofrettage thick-walled cylinders with defects.