The molecular dynamics （MD） simulation and the modified analytical embedded-atom method （MAEAM） were used to study the influence of a He atom on the movement of the（a/2）？110？{111} edge dislocation in Ni. First...The molecular dynamics （MD） simulation and the modified analytical embedded-atom method （MAEAM） were used to study the influence of a He atom on the movement of the（a/2）？110？{111} edge dislocation in Ni. First, the calculated Burgers vector distribution shows that the equilibrium dissociation distance （Ded） and the stacking fault energy （Esf） between two partial edge dislocations are about 25.95 ？ and 108 mJ/m2, respectively. Then, the obtained formation energies （Ef） of a He atom at some different sites demonstrate that the He atom is attracted and repelled in the tension and compression regions, respectively. And the He？dislocation interaction reveals that an interstitial He atom plays a more significant role in the dislocation movement than a substitutional He atom. Finally, it is found that the movement of an interstitial He atom is apparent as the first partial dislocation bypasses and the edge dislocation offers fast-diffusion path for the migration of a He atom.展开更多
The thermal elasto-hydrodynamic lubrication characteristics of the internal meshing gears in a planetary gear train under vibrations were examined considering the influence of the modification coefficient and time-var...The thermal elasto-hydrodynamic lubrication characteristics of the internal meshing gears in a planetary gear train under vibrations were examined considering the influence of the modification coefficient and time-varying meshing stiffness.Based on dynamic theory of the gear system,a dynamic model of the planetary gear train was established.The lubrication performances of modified gear systems under vibrations and static loads were analyzed.Compared with other transmission types,the best lubrication effect could be produced by the positive transmission.A thicker lubricating oil film could be formed,and the friction coefficient and oil film flash temperature are the smallest.Increasing modification coefficient improves the lubrication performance continuously but intensifies the engage-in and tooth-change impact.For the planetary and inner gears,the increase in the modification coefficient also leads a decrease in the oil film stiffness.展开更多
基金Project(ZL1405)supported by the Talent Project of Lingnan Normal University,China
文摘The molecular dynamics （MD） simulation and the modified analytical embedded-atom method （MAEAM） were used to study the influence of a He atom on the movement of the（a/2）？110？{111} edge dislocation in Ni. First, the calculated Burgers vector distribution shows that the equilibrium dissociation distance （Ded） and the stacking fault energy （Esf） between two partial edge dislocations are about 25.95 ？ and 108 mJ/m2, respectively. Then, the obtained formation energies （Ef） of a He atom at some different sites demonstrate that the He atom is attracted and repelled in the tension and compression regions, respectively. And the He？dislocation interaction reveals that an interstitial He atom plays a more significant role in the dislocation movement than a substitutional He atom. Finally, it is found that the movement of an interstitial He atom is apparent as the first partial dislocation bypasses and the edge dislocation offers fast-diffusion path for the migration of a He atom.
基金Projects(51575289,51705270)supported by the National Natural Science Foundation of China。
文摘The thermal elasto-hydrodynamic lubrication characteristics of the internal meshing gears in a planetary gear train under vibrations were examined considering the influence of the modification coefficient and time-varying meshing stiffness.Based on dynamic theory of the gear system,a dynamic model of the planetary gear train was established.The lubrication performances of modified gear systems under vibrations and static loads were analyzed.Compared with other transmission types,the best lubrication effect could be produced by the positive transmission.A thicker lubricating oil film could be formed,and the friction coefficient and oil film flash temperature are the smallest.Increasing modification coefficient improves the lubrication performance continuously but intensifies the engage-in and tooth-change impact.For the planetary and inner gears,the increase in the modification coefficient also leads a decrease in the oil film stiffness.
