Analysis of Residual Stress of Auto-fretted Barrel Based on Unified Strength Theory
Based on the unified strength theory,considering the influence of material tension-compres-sion anisotropy and Bauschinger effect,a bilinear strengthening material model was used to analyze the auto-fretted barrel,and analytical solutions of loading stress,unloading stress,residual stress and working stress of the barrel were derived.The calculation formulas of the elastic-plastic interface radius and reverse yield radius were obtained,and the calculation methods of the optimum autofrettage degree and autofrettage pressure were proposed.The correctness of the theoretical solutions was verified by comparison with the experimental data,and the influences of material tensile strength ratio,intermedia-te stress coefficient and other parameters on the residual stress,elastic-plastic interface radius,reverse yield radius and optimum autofrettage pressure of the barrel were analyzed.The results show that the reverse yield radius,elastic-plastic interface radius and residual stress at the elastic-plastic interface are proportional to the material tensile strength ratio and inversely proportional to the intermediate stress coefficient;the optimum autofrettage pressure is inversely proportional to the material tensile strength ratio and proportional to the intermediate stress coefficient.
residual stressunified strength theoryBauschinger effectdual linear strengthening modelreverse yield
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