It is well known that groove texture with a careful design can be used to enhance the load‐carrying capacity of oil film under the conditions of hydrodynamic lubrication.In this study,a general parametric model was d...It is well known that groove texture with a careful design can be used to enhance the load‐carrying capacity of oil film under the conditions of hydrodynamic lubrication.In this study,a general parametric model was developed,and agenetic algorithm‐sequential quadratic programming hybrid method was adopted to obtain the global‐optimum profile of the groove texture.The optimized profiles at different rotating speeds are all chevrons.The numerical analysis results verified the effect of the optimization.In addition to the numerical optimization,experiments were conducted to validate the superiority of the optimized results.The experimental results show that the optimized groove texture can efficiently reduce the coefficient of friction(COF)and the temperature rise of the specimen.In particular,the optimized groove textures can achieve stable ultra‐low COF values(COF<0.01)under certain conditions.展开更多
In this study,the tribological behaviors of graphene as a lubricant additive for steel/copper and steel/steel friction pairs were compared.For the steel/copper friction pair,the graphene sheets remarkably decreased th...In this study,the tribological behaviors of graphene as a lubricant additive for steel/copper and steel/steel friction pairs were compared.For the steel/copper friction pair,the graphene sheets remarkably decreased the coefficient of friction and wear scar depth under low loads,but these slightly increased under high loads.The steel/steel friction pair showed excellent tribological properties even under high loads.Severe plastic deformation on the copper surface reduced the stability of the graphene tribofilm because of a rough copper transfer film on the steel during the running-in period.The results provide a better understanding of the mechanism of graphene as a lubricant additive.展开更多
文摘It is well known that groove texture with a careful design can be used to enhance the load‐carrying capacity of oil film under the conditions of hydrodynamic lubrication.In this study,a general parametric model was developed,and agenetic algorithm‐sequential quadratic programming hybrid method was adopted to obtain the global‐optimum profile of the groove texture.The optimized profiles at different rotating speeds are all chevrons.The numerical analysis results verified the effect of the optimization.In addition to the numerical optimization,experiments were conducted to validate the superiority of the optimized results.The experimental results show that the optimized groove texture can efficiently reduce the coefficient of friction(COF)and the temperature rise of the specimen.In particular,the optimized groove textures can achieve stable ultra‐low COF values(COF<0.01)under certain conditions.
基金This work was supported by National Natural Science Foundation of China(Nos.51527901 and 51335005)the National Key Basic Research Program of China(973 Program,No.2014CB046404)Tribology Science Fund of State Key Laboratory of Tribology(No.SKLTKF18A02).
文摘In this study,the tribological behaviors of graphene as a lubricant additive for steel/copper and steel/steel friction pairs were compared.For the steel/copper friction pair,the graphene sheets remarkably decreased the coefficient of friction and wear scar depth under low loads,but these slightly increased under high loads.The steel/steel friction pair showed excellent tribological properties even under high loads.Severe plastic deformation on the copper surface reduced the stability of the graphene tribofilm because of a rough copper transfer film on the steel during the running-in period.The results provide a better understanding of the mechanism of graphene as a lubricant additive.
