Papers by Author: Ning Li

Abstract: Resource sharing is based on network resource sharing, in which many Internet enthusiasts share the information collected by themselves with the world through some platforms for not pursuing any interests. Along with the wide application of computer network in the groups of users, a good communication platform between the Internet and users has begun to be produced, and also network resources gradually trend to the development of resources sharing, but are no longer simply enjoyed by a certain user. To analyze and further know the advantages of computer network resource sharing, it is necessary to combine with their actual application conditions. This is analyzed in this paper.

Abstract: A thermal-mechanical coupled analysis of superplastic differential temperature deep drawing (SDTDD) with the MARC finite element code is performed in this paper. Initial drawing blank of an AA5083 bracket was calculated and adjusted according to the simulation result. During the SDTDD simulation, the power-law constitutive model of AA5083 was established as function of temperature and implanted in software MARC through new complied subroutine. Under the guide of the numerical simulation, the die was fabricated and the AA5083 bracket was successfully manufactured via superplastic differential temperature deep drawing. In forming practice, the temperature of female die was kept at 525°C, i.e. the optimal superplastic temperature of AA5083, and the punch was cooled by the flowing water throughout the forming process. The drawing velocity of punch was 0.1mm/s. Results revealed that the formed bracket had a sound uniform thickness distribution. Good agreement was obtained between the formed thickness profiles and the predicted ones.

Abstract: A mechanical model of the pressure-sensitive dilatant material is established in order to investigate the viscous effect in mode I quasi-static growing crack-tip field. The constitutive equations on the pressure-sensitive dilatant material are deducted. Through asymptotic analysis, it is shown that in the stable creep growing stage, the elastic-deformation and the visco-deformation are equally dominant in the near-tip field, as . The asymptotic solutions of separative variable in the crack-tip field of plane stress mode I quasi-static are aslo obtained. According to numerical calculation, the curves of stress, strain and displacement in terms of various parameters are given. The asymptotic solutions of quasi-static growing crack-tip field gained here can conveniently degenerate the incompressible case, when the Poisson ratio , named as HR field. The conclusions can provide the references for further studying the dynamic growing crack-tip field in the pressure-sensitive dilatant material.

Abstract: A mechanical model of the pressure-sensitive dilatant material is established in order to investigate the viscous effect in quasi-static growing crack-tip field. The constitutive equations on the pressure-sensitive dilatant material are deducted. Through asymptotic analysis, it is shown that in the stable creep growing stage, the elastic-deformation and the visco-deformation are equally dominant in the near-tip field, as . The asymptotic solutions of separative variable in the crack-tip field of plane stress mode II quasi-static are aslo obtained. According to numerical calculation, the curves of stress, strain and displacement in terms of various parameters are given. The asymptotic solutions of quasi-static growing crack-tip field gained here can conveniently degenerate the incompressible case, when the Poisson ratio , named as HR field. The conclusions can provide the references for further studying the dynamic growing crack-tip field in the pressure-sensitive dilatant material.