Tubular members subject to combined pitting corrosion and crack damage were numerically studied to clarify the reduction of ultimate strength and failure behavior,based on numerical models validated against available ...Tubular members subject to combined pitting corrosion and crack damage were numerically studied to clarify the reduction of ultimate strength and failure behavior,based on numerical models validated against available experi-ments.The effects of length,location and inclined angle of a crack under combined damage were studied to disclose the mechanism of interaction between the crack and corrosion pits.The methods,named as linear superposition directly accumulating the effects of solo crack and solo pitting damage,as well as crack projection transferring an inclined crack to a transverse one,were discussed and verified in the view of assessing ultimate strength of tubular members with combined damage.It was shown that the former is practical but complex while the next always over-estimates the residual strength.Besides,the location and inclined angle of a crack have a subtle effect on the reduction of ultimate strength under combined damage,especially at higher level of pitting damage,due to the synergistic effect between corrosion pits and cracks.Such effect can lead to early occurrence of plasticity and local buckling by inducing stress interaction between crack tips and pits,and causing more significant strength reduction compared with a solo type of damage.A practical method was proposed to determine the loss ratio of cross-sectional area on the equivalent weakest section of a damaged member.Based on the loss ratio,a formula was presented to predict the ultimate strength of damaged members with combined damage,showing good applicability.展开更多
A great deal of attention has been focused on discharge plasma as it can rapidly decompose N2O without additives,which is not only a kind of greenhouse gas but also a kind of damages to the ozone layer.The thermal equ...A great deal of attention has been focused on discharge plasma as it can rapidly decompose N2O without additives,which is not only a kind of greenhouse gas but also a kind of damages to the ozone layer.The thermal equilibrium plasma is chosen to combine with catalysts to decompose N2O,and its characteristics are analyzed in the present paper.The results indicate that NO and NO2 were formed besides N2 and O2 during N2O decomposition when N2O was treated merely by discharge plasma.Concentration of NO declined greatly when the discharge plasma was combined with catalysts.Results of Raman spectra analysis on CeO2,Ce（0.75）Zr（0.25）O2and Ce（0.5）Zr（0.5）O2 imply that the products selectivity has been obviously improved in discharge plasma decomposing N2O because of the existence of massive oxygen vacancies over the composite oxide catalysts.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51879124)。
文摘Tubular members subject to combined pitting corrosion and crack damage were numerically studied to clarify the reduction of ultimate strength and failure behavior,based on numerical models validated against available experi-ments.The effects of length,location and inclined angle of a crack under combined damage were studied to disclose the mechanism of interaction between the crack and corrosion pits.The methods,named as linear superposition directly accumulating the effects of solo crack and solo pitting damage,as well as crack projection transferring an inclined crack to a transverse one,were discussed and verified in the view of assessing ultimate strength of tubular members with combined damage.It was shown that the former is practical but complex while the next always over-estimates the residual strength.Besides,the location and inclined angle of a crack have a subtle effect on the reduction of ultimate strength under combined damage,especially at higher level of pitting damage,due to the synergistic effect between corrosion pits and cracks.Such effect can lead to early occurrence of plasticity and local buckling by inducing stress interaction between crack tips and pits,and causing more significant strength reduction compared with a solo type of damage.A practical method was proposed to determine the loss ratio of cross-sectional area on the equivalent weakest section of a damaged member.Based on the loss ratio,a formula was presented to predict the ultimate strength of damaged members with combined damage,showing good applicability.
基金supported by National Natural Science Foundation of China(No.50677026)the Applied Basic Research Program of Wuhan,China(No.2015060101010068)
文摘A great deal of attention has been focused on discharge plasma as it can rapidly decompose N2O without additives,which is not only a kind of greenhouse gas but also a kind of damages to the ozone layer.The thermal equilibrium plasma is chosen to combine with catalysts to decompose N2O,and its characteristics are analyzed in the present paper.The results indicate that NO and NO2 were formed besides N2 and O2 during N2O decomposition when N2O was treated merely by discharge plasma.Concentration of NO declined greatly when the discharge plasma was combined with catalysts.Results of Raman spectra analysis on CeO2,Ce（0.75）Zr（0.25）O2and Ce（0.5）Zr（0.5）O2 imply that the products selectivity has been obviously improved in discharge plasma decomposing N2O because of the existence of massive oxygen vacancies over the composite oxide catalysts.
