A constitutive model of unsaturated soils with coupling capillary hystere- sis and skeleton deformation is developed and implemented in a fully coupled transient hydro-mechanical finite-element model （computer code U...A constitutive model of unsaturated soils with coupling capillary hystere- sis and skeleton deformation is developed and implemented in a fully coupled transient hydro-mechanical finite-element model （computer code U-DYSAC2）. The obtained re- sults are compared with experimental results, showing that the proposed constitutive model can simulate the main mechanical and hydraulic behavior of unsaturated soils in a unified framework. The non-lineaxity of the soil-water characteristic relation is treated in a similar way of elastoplasticity. Two constitutive relations axe integrated by an implicit return-mapping scheme similar to that developed for saturated soils. A consistent tan- gential modulus is derived to preserve the asymptotic rate of the quadratic convergence of Newton＇s iteration. Combined with the integration of the constitutive model, a complete finite-element formulation of coupling hydro-mechanical problems for unsaturated soils is presented. A number of practical problems with different given initial and boundary conditions are analyzed to illustrate the performance and capabilities of the finite-element model.展开更多
The surface defect distribution in stainless steel irradiated with intensepulsed ion beam (IPIB) of current density above 60A/cm^2 and acceleration voltage 300-500ke V wasdiscussed and analyzed. The defects near the s...The surface defect distribution in stainless steel irradiated with intensepulsed ion beam (IPIB) of current density above 60A/cm^2 and acceleration voltage 300-500ke V wasdiscussed and analyzed. The defects near the surface of stainless steel were generated in two ways:(1) generated by the bombardment of energetic ions and (2) induced by the high level stress near thesurface. Thus the temperature and stress distributions near the steel surface were calculated bymeans of our STEIPIB code, which treated with the thermal-dynamical process in the target irradiatedby the IPIB. Based on these distributions, the generations and movements of these defects werediscussed and compared with the experiment results.展开更多
基金supported by the National Natural Science Foundation of China(No.11072255)the Natural Science Foundation of Guangxi Province(No.2011GXNSFE018004)
文摘A constitutive model of unsaturated soils with coupling capillary hystere- sis and skeleton deformation is developed and implemented in a fully coupled transient hydro-mechanical finite-element model （computer code U-DYSAC2）. The obtained re- sults are compared with experimental results, showing that the proposed constitutive model can simulate the main mechanical and hydraulic behavior of unsaturated soils in a unified framework. The non-lineaxity of the soil-water characteristic relation is treated in a similar way of elastoplasticity. Two constitutive relations axe integrated by an implicit return-mapping scheme similar to that developed for saturated soils. A consistent tan- gential modulus is derived to preserve the asymptotic rate of the quadratic convergence of Newton＇s iteration. Combined with the integration of the constitutive model, a complete finite-element formulation of coupling hydro-mechanical problems for unsaturated soils is presented. A number of practical problems with different given initial and boundary conditions are analyzed to illustrate the performance and capabilities of the finite-element model.
基金This work is supported by the National Natural Science Foundation of China (Grant No. 19975003 and 10175003).
文摘The surface defect distribution in stainless steel irradiated with intensepulsed ion beam (IPIB) of current density above 60A/cm^2 and acceleration voltage 300-500ke V wasdiscussed and analyzed. The defects near the surface of stainless steel were generated in two ways:(1) generated by the bombardment of energetic ions and (2) induced by the high level stress near thesurface. Thus the temperature and stress distributions near the steel surface were calculated bymeans of our STEIPIB code, which treated with the thermal-dynamical process in the target irradiatedby the IPIB. Based on these distributions, the generations and movements of these defects werediscussed and compared with the experiment results.
