The microstructure and properties of high carbonic-chromium cast steel subjected to different hot deformation ratios were studied.The experimental results show that the microstructure and properties of high carbonic-c...The microstructure and properties of high carbonic-chromium cast steel subjected to different hot deformation ratios were studied.The experimental results show that the microstructure and properties of high carbonic-chromium cast steel are obviously improved after hot deformation,and the best mechanical properties of the cast steel can be obtained under hot deformation ratio of 40 %-50 %,which leads to the morphology change of eutectic carbide and the precipitation of granular carbides.展开更多
Discusses the elastic deformation of ellipsoidal shell of different axis ratio under inner pressure during hydraulic bulging forming with theoretical results in good agreement with actual result, thereby providing the...Discusses the elastic deformation of ellipsoidal shell of different axis ratio under inner pressure during hydraulic bulging forming with theoretical results in good agreement with actual result, thereby providing theoretical basis for hydraulic bulging forming of ellipsoidal shell.展开更多
The aim of this note is to study the effect of negative Poisson’s ratio on the quasi-static deformation of a poroelastic half-space with anisotropic permeability and compressible fluid and solid constituents by surfa...The aim of this note is to study the effect of negative Poisson’s ratio on the quasi-static deformation of a poroelastic half-space with anisotropic permeability and compressible fluid and solid constituents by surface loads. Two particular cases considered are: two-dimensional normal strip loading and axisymmetric normal disc loading. It is found that a negative Poisson’s ratio makes the Mandel-Cryer effect more prominent. It also results in an increase in the magnitude of the surface settlement.展开更多
Surrounding rocks at different locations are generally subjected to different stress paths during the process of deep hard rock excavation.In this study,to reveal the mechanical parameters of deep surrounding rock und...Surrounding rocks at different locations are generally subjected to different stress paths during the process of deep hard rock excavation.In this study,to reveal the mechanical parameters of deep surrounding rock under different stress paths,a new cyclic loading and unloading test method for controlled true triaxial loading and unloading and principal stress direction interchange was proposed,and the evolution of mechanical parameters of Shuangjiangkou granite under different stress paths was studied,including the deformation modulus,elastic deformation increment ratios,fracture degree,cohesion and internal friction angle.Additionally,stress path coefficient was defined to characterize different stress paths,and the functional relationships among the stress path coefficient,rock fracture degree difference coefficient,cohesion and internal friction angle were obtained.The results show that during the true triaxial cyclic loading and unloading process,the deformation modulus and cohesion gradually decrease,while the internal friction angle gradually increases with increasing equivalent crack strain.The stress path coefficient is exponentially related to the rock fracture degree difference coefficient.As the stress path coefficient increases,the degrees of cohesion weakening and internal friction angle strengthening decrease linearly.During cyclic loading and unloading under true triaxial principal stress direction interchange,the direction of crack development changes,and the deformation modulus increases,while the cohesion and internal friction angle decrease slightly,indicating that the principal stress direction interchange has a strengthening effect on the surrounding rocks.Finally,the influences of the principal stress interchange direction on the stabilities of deep engineering excavation projects are discussed.展开更多
基金Item Sponsored by Guiding Program of Science and Technology Research of Hebei Province of China(94122123)
文摘The microstructure and properties of high carbonic-chromium cast steel subjected to different hot deformation ratios were studied.The experimental results show that the microstructure and properties of high carbonic-chromium cast steel are obviously improved after hot deformation,and the best mechanical properties of the cast steel can be obtained under hot deformation ratio of 40 %-50 %,which leads to the morphology change of eutectic carbide and the precipitation of granular carbides.
文摘Discusses the elastic deformation of ellipsoidal shell of different axis ratio under inner pressure during hydraulic bulging forming with theoretical results in good agreement with actual result, thereby providing theoretical basis for hydraulic bulging forming of ellipsoidal shell.
文摘The aim of this note is to study the effect of negative Poisson’s ratio on the quasi-static deformation of a poroelastic half-space with anisotropic permeability and compressible fluid and solid constituents by surface loads. Two particular cases considered are: two-dimensional normal strip loading and axisymmetric normal disc loading. It is found that a negative Poisson’s ratio makes the Mandel-Cryer effect more prominent. It also results in an increase in the magnitude of the surface settlement.
基金the financial support from the National Natural Science Foundation of China(Grant Nos.51839003 and 42207221).
文摘Surrounding rocks at different locations are generally subjected to different stress paths during the process of deep hard rock excavation.In this study,to reveal the mechanical parameters of deep surrounding rock under different stress paths,a new cyclic loading and unloading test method for controlled true triaxial loading and unloading and principal stress direction interchange was proposed,and the evolution of mechanical parameters of Shuangjiangkou granite under different stress paths was studied,including the deformation modulus,elastic deformation increment ratios,fracture degree,cohesion and internal friction angle.Additionally,stress path coefficient was defined to characterize different stress paths,and the functional relationships among the stress path coefficient,rock fracture degree difference coefficient,cohesion and internal friction angle were obtained.The results show that during the true triaxial cyclic loading and unloading process,the deformation modulus and cohesion gradually decrease,while the internal friction angle gradually increases with increasing equivalent crack strain.The stress path coefficient is exponentially related to the rock fracture degree difference coefficient.As the stress path coefficient increases,the degrees of cohesion weakening and internal friction angle strengthening decrease linearly.During cyclic loading and unloading under true triaxial principal stress direction interchange,the direction of crack development changes,and the deformation modulus increases,while the cohesion and internal friction angle decrease slightly,indicating that the principal stress direction interchange has a strengthening effect on the surrounding rocks.Finally,the influences of the principal stress interchange direction on the stabilities of deep engineering excavation projects are discussed.
