摘要
基于空间机构的运动特性,考虑空间颤振环境的影响,采用粗粒化分子动力学研究MoS_(2)/Ag薄膜的碰撞滑动接触摩擦性能,建立颤振环境碰撞滑动接触摩擦的粗粒化分子动力学模型,对比了纯Ag和MoS_(2)/Ag薄膜的摩擦性能,研究了初始碰撞速度、滑动速度以及空间温度对碰撞滑动接触摩擦过程的影响.结果表明:与纯Ag相比,MoS_(2)/Ag薄膜表现出更优异的摩擦性能;压头碰撞速度对动能有一定的贡献,初始碰撞速度的增加会增大压头压入基体的深度,使得平均摩擦力增大;滑动速度的增加会加剧原子间的相互剪切摩擦,使平均摩擦力增加;MoS_(2)/Ag薄膜在100~500 K温度范围内表现出良好的摩擦性能,当空间温度为600 K时,其摩擦性能降低,并伴随着MoS_(2)膜的破裂.
Space environment is greatly different from atmospheric environment in many aspects,e.g.energetic atomic oxygen,ultra-high vacuum,microgravity,alternate extreme temperature,solar UV radiation,and this produces a vital influence on aerospace devices’reliability and life durability.In space environment,the vacuum and microgravity environments always induce high friction forces between contact surfaces.In vacuum,adhesive effects induce a high adhesion component of a friction force.Under microgravity,the irregular collision between contact bodies induced by the disturbance occurs all the time,which has a great influence on a ploughing component.The kinetic energy of a contact body will be converted to the mechanical energy during the collisionprocess,and the friction forces could be underestimated if the collision effects are neglected.As a result,the adhesive and collision effects should be considered simultaneously during the simulation of friction behaviors under space environment.As one of the most widely used solid lubricants in space environment,molybdenum disulfide(MoS_(2))can significantly improve the tribological properties of friction pairs.Moreover,soft metals are always used as solid lubricants in spacecraft,and a soft metal Ag could be used to weaken the collision effects.The combination of MoS_(2) and Ag may provide synergistic lubricating performance.To investigate the influence of MoS_(2)/Ag films on the friction behaviors,a monolayer MoS_(2) film was coated on the Ag surface to form MoS_(2)/Ag films.It is difficult to perform microgravity friction experiments on the earth,and the chance to take a friction experiment in space is scarce.Therefore,in this work,based on the motion characteristics of a space mechanism,a coarse-grained molecular dynamics method was used to study the friction properties of collision sliding contacts between a rigid indenter and the MoS_(2)/Ag films considering the influence of the vibration in space environment.A coarse-grained molecular dynamics model of the collision sl
作者
杜晶涛
佟瑞庭
王云峰
权泽芬
DU Jingtao;TONG Ruiting;WANG Yunfeng;QUAN Zefen(Shaanxi Engineering Laboratory for Transmissions and Controls,Northwestern Polytechnical University,Shaanxi Xi’an 710072,China;Shanghai Aircraft Design and Research Institute,Shanghai 200436,China)
出处
《摩擦学学报》
EI
CAS
CSCD
北大核心
2022年第4期669-679,共11页
Tribology
基金
国家自然科学基金(52075444,51675429)
中央高校基本科研业务费专项资金(31020190503004)
国家自然科学基金重点项目(51535009)资助。
