1.IntroductionSo far there are few people who studythe relationship between the criticalhydrogen concentration and the stress forhvdrogen induced cracking (CCHIC)quantitatively.Several researchers have cal-culated the...1.IntroductionSo far there are few people who studythe relationship between the criticalhydrogen concentration and the stress forhvdrogen induced cracking (CCHIC)quantitatively.Several researchers have cal-culated the CCHIC of steels under no stressby means of H permeation method,but no展开更多
The effect of varying the temperature and the concentration of ammonium nitrate solution on the stress corrosion cracking (SCC) susceptibility of mild steel is studied. An increase in the temperature causes a decrease...The effect of varying the temperature and the concentration of ammonium nitrate solution on the stress corrosion cracking (SCC) susceptibility of mild steel is studied. An increase in the temperature causes a decrease in the stress corrosion life. It appears that the susceptibility in the range 368 K to 380 K was greater than at other temperatures. Near the boiling point corrosion and stress corrosion occurs, at the boiling point, the cracking was associated with a high rate of general corrosion. Microscopic examination after stress corrosion testing in 10Wt%, 20Wt%, and 52Wt% NH4NO3 solution revealed that in all cases there was severe intergranular attack, especially at the high concentration.展开更多
In order to ensure safe mining and reduce surface damage in shallow multi-seam mining,the failure characteristics of interburden strata with different coal pillars offset distances between pillars in the upper and low...In order to ensure safe mining and reduce surface damage in shallow multi-seam mining,the failure characteristics of interburden strata with different coal pillars offset distances between pillars in the upper and lower seams,the distribution characteristics of stress concentration in coal pillars,and the development characteristics of stratum cracks and subsidence were investigated by physical and UDEC2D simulation.Meanwhile,the effect of different coal pillar offset distances on stress concentration of coal pillar and development of stratum cracks were studied.Based on those results,a formula for safe mining and reducing surface damage was established,which provided a theoretical basis for safe and environmentally friendly mining in shallow multi-seam.According to the results,the optimal coal pillar offset distance(the side to side horizontal distance of the upper and lower coal pillars)between the upper and lower coal seams was developed to reduce the stress concentration of coal pillars and surface damage.The results of this study have been applied in Ningtiaota coal mine and have achieved good results in safe and environmentally friendly mining.展开更多
A new experimental method was developed to simulate the generation of the surface transversal crack on the continuous casting slab with a discontinuous sample. A high temperature property of steel named"the sensi...A new experimental method was developed to simulate the generation of the surface transversal crack on the continuous casting slab with a discontinuous sample. A high temperature property of steel named"the sensitivity to the stress concentration of steel at high temperature"was defined to evaluate the effect of stress concentration on thermal plasticity of steel. "The sensitivity parameter to the stress concentration of steel at high temperature"was available to determine the temperature range in which steel is sensitive to the stress concentration.展开更多
In this paper, the analytical solution of stress field for a strained reinforcement layer bonded to a lip-shaped crack under a remote mode III uniform load and a concentrated load is obtained explicitly in the series ...In this paper, the analytical solution of stress field for a strained reinforcement layer bonded to a lip-shaped crack under a remote mode III uniform load and a concentrated load is obtained explicitly in the series form by using the technical of conformal mapping and the method of analytic continuation. The effects of material combinations, bond of interface and geometric configurations on interfaciai stresses generated by eigenstrain, remote load and concentrated load are studied. The results show that the stress concentration and interfaciai stresses can be reduced by rational material combinations and geometric configurations designs for different load forms.展开更多
The problem of scattering of SH-wave by a circular cavity and an arbitrary beeline crack in right-angle plane was investigated using the methods of Green's function,complex variables and muti-polar coordinates.Fir...The problem of scattering of SH-wave by a circular cavity and an arbitrary beeline crack in right-angle plane was investigated using the methods of Green's function,complex variables and muti-polar coordinates.Firstly,we constructed a suitable Green's function,which is an essential solution to the displacement field for the elastic right-angle plane possessing a circular cavity while bearing out-of-plane harmonic line source load at arbitrary point.Secondly,based on the method of crack-division,integration for solution was established,then expressions of displacement and stress were obtained while crack and circular cavities were both in existence.Finally,the dynamic stress concentration factor around the circular cavity and the dynamic stress intensity factor at crack tip were discussed to the cases of different parameters in numerical examples.Calculation results show that the crack produces adverse engineering influence on both of the dynamic stress concentration factor and the dynamic stress intensity factor.展开更多
Wave propagation in an infinite elastic piezoelectric medium with a circular cavity and an impermeable crack subjected to steady-state anti-plane shearing was studied based on Green's function and the crack-divisi...Wave propagation in an infinite elastic piezoelectric medium with a circular cavity and an impermeable crack subjected to steady-state anti-plane shearing was studied based on Green's function and the crack-division technique.Theoretical solutions were derived for the whole elastic displacement and electric potential field in the interaction between the circular cavity and the impermeable crack.Expressions were obtained on the dynamic stress concentration factor(DSCF) at the cavity's edge,the dynamic stress intensity factor(DSIF) and the dynamic electric displacement intensity factor(DEDIF) at the crack tip.Numerical solutions were performed and plotted with different incident wave numbers,parameters of piezoelectric materials and geometries of the structure.Finally,some of the calculation results were compared with the case of dynamic anti-plane interaction of a permeable crack and a circular cavity in an infinite piezoelectric medium.This paper can provide a valuable reference for the design of piezoelectric actuators and sensors widely used in marine structures.展开更多
文摘1.IntroductionSo far there are few people who studythe relationship between the criticalhydrogen concentration and the stress forhvdrogen induced cracking (CCHIC)quantitatively.Several researchers have cal-culated the CCHIC of steels under no stressby means of H permeation method,but no
文摘The effect of varying the temperature and the concentration of ammonium nitrate solution on the stress corrosion cracking (SCC) susceptibility of mild steel is studied. An increase in the temperature causes a decrease in the stress corrosion life. It appears that the susceptibility in the range 368 K to 380 K was greater than at other temperatures. Near the boiling point corrosion and stress corrosion occurs, at the boiling point, the cracking was associated with a high rate of general corrosion. Microscopic examination after stress corrosion testing in 10Wt%, 20Wt%, and 52Wt% NH4NO3 solution revealed that in all cases there was severe intergranular attack, especially at the high concentration.
基金The article was funded by the National Natural Science Foundation of China(Nos.51674190 and 52074211)the Natural Science Basic Research Program of Shaanxi(Nos.2019JQ-798 and 2019JLP-08).The authors also thank the reviewers for their patient work.
文摘In order to ensure safe mining and reduce surface damage in shallow multi-seam mining,the failure characteristics of interburden strata with different coal pillars offset distances between pillars in the upper and lower seams,the distribution characteristics of stress concentration in coal pillars,and the development characteristics of stratum cracks and subsidence were investigated by physical and UDEC2D simulation.Meanwhile,the effect of different coal pillar offset distances on stress concentration of coal pillar and development of stratum cracks were studied.Based on those results,a formula for safe mining and reducing surface damage was established,which provided a theoretical basis for safe and environmentally friendly mining in shallow multi-seam.According to the results,the optimal coal pillar offset distance(the side to side horizontal distance of the upper and lower coal pillars)between the upper and lower coal seams was developed to reduce the stress concentration of coal pillars and surface damage.The results of this study have been applied in Ningtiaota coal mine and have achieved good results in safe and environmentally friendly mining.
文摘A new experimental method was developed to simulate the generation of the surface transversal crack on the continuous casting slab with a discontinuous sample. A high temperature property of steel named"the sensitivity to the stress concentration of steel at high temperature"was defined to evaluate the effect of stress concentration on thermal plasticity of steel. "The sensitivity parameter to the stress concentration of steel at high temperature"was available to determine the temperature range in which steel is sensitive to the stress concentration.
基金Project supported by the National Natural Science Foundation of China(Nos.10872065 and 50801025)the State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body(No. 60870005)the Doctor Station Fund of Institutions of Higher Learning(No.200805320023)
文摘In this paper, the analytical solution of stress field for a strained reinforcement layer bonded to a lip-shaped crack under a remote mode III uniform load and a concentrated load is obtained explicitly in the series form by using the technical of conformal mapping and the method of analytic continuation. The effects of material combinations, bond of interface and geometric configurations on interfaciai stresses generated by eigenstrain, remote load and concentrated load are studied. The results show that the stress concentration and interfaciai stresses can be reduced by rational material combinations and geometric configurations designs for different load forms.
文摘The problem of scattering of SH-wave by a circular cavity and an arbitrary beeline crack in right-angle plane was investigated using the methods of Green's function,complex variables and muti-polar coordinates.Firstly,we constructed a suitable Green's function,which is an essential solution to the displacement field for the elastic right-angle plane possessing a circular cavity while bearing out-of-plane harmonic line source load at arbitrary point.Secondly,based on the method of crack-division,integration for solution was established,then expressions of displacement and stress were obtained while crack and circular cavities were both in existence.Finally,the dynamic stress concentration factor around the circular cavity and the dynamic stress intensity factor at crack tip were discussed to the cases of different parameters in numerical examples.Calculation results show that the crack produces adverse engineering influence on both of the dynamic stress concentration factor and the dynamic stress intensity factor.
基金Supported by the Natural Science Foundation of Heilongjiang Province of China (A00-10)the Basis Research Foundation of Harbin Engineering University (HEUF04008)
文摘Wave propagation in an infinite elastic piezoelectric medium with a circular cavity and an impermeable crack subjected to steady-state anti-plane shearing was studied based on Green's function and the crack-division technique.Theoretical solutions were derived for the whole elastic displacement and electric potential field in the interaction between the circular cavity and the impermeable crack.Expressions were obtained on the dynamic stress concentration factor(DSCF) at the cavity's edge,the dynamic stress intensity factor(DSIF) and the dynamic electric displacement intensity factor(DEDIF) at the crack tip.Numerical solutions were performed and plotted with different incident wave numbers,parameters of piezoelectric materials and geometries of the structure.Finally,some of the calculation results were compared with the case of dynamic anti-plane interaction of a permeable crack and a circular cavity in an infinite piezoelectric medium.This paper can provide a valuable reference for the design of piezoelectric actuators and sensors widely used in marine structures.