基于界面力学分析的轴承钢表面固体薄膜承载能力研究

发布时间：2018-03-07 02:05

本文选题：界面力学分析　切入点：复变函数镜像法　出处：《哈尔滨工业大学》2017年博士论文　论文类型：学位论文

【摘要】：固体薄膜润滑在空天、星际和深海等极端环境条件下的机械装置中广泛应用,其在重载等工况下的工作承载能力和运行寿命是机械设计关注的核心指标之一。本文以“探月工程”主轴钻杆的动力传输与支撑部件——密珠轴系重载下的表面固体薄膜润滑设计和实施为应用背景,探索轴承钢表面常用固体润滑薄膜在重载作用下的失效过程和界面力学机制,为密珠轴系的结构与润滑设计提供依据。建立了固体薄膜表面在集中单元力作用下的二维和三维界面力学分析模型,采用复变函数镜像法,利用固体薄膜的自由表面和连续界面两个边界条件实现不同阶次的镜像迭代,计算固体薄膜和基底的每阶镜像递推系数使表面和界面边界条件得到满足,最终求解出界面应力和变形的解析解。通过对集中力的积分,获得膜基系统在法向和切向分布力协同作用下的二维和三维界面力学分析模型。针对常见球形赫兹点接触形式,为简化三维积分过程,利用横观各向同性应力势函数的解,通过镜像法直接获得了膜基系统界面应力与变形解。通过与有限元法进行对比验证,该计算方法具有相同的精度和更快的速度,且对不同工况参数具有更好的适应性。针对机械零件高副接触中常用的层状二硫化钼(Molybdenum disulfide,Mo S2)薄膜和硬脆性类金刚石碳(Diamond-like Carbon,DLC)膜,采用球-盘摩擦和纳米/微米划痕方法测试了随载荷变化的薄膜摩擦与失效行为;利用纳米压痕测试获取固体薄膜和基底的弹性属性参数,结合界面力学计算,分析了固体薄膜承载过程中的界面应力响应规律和失效过程参数变化。Mo S2固体薄膜在低界面剪切应力下发生膜内层间滑移,而在高界面剪切应力下发生片状剥落;DLC膜则表现为重载下接触后端薄膜拉伸断裂和前端膜基界面错位失效形式。最后,针对钻杆密珠轴系的载荷需求开展了密珠轴系结构设计和内部载荷分析,根据固体薄膜失效特点及边界参数核算了二硫化钼和类金刚石碳薄膜润滑下的膜基界面应力状态;利用密珠轴系模拟工况试验平台完成了固体润滑的应用性能测试。
[Abstract]:Solid film lubrication is widely used in machinery under extreme conditions such as sky, interstellar and deep sea. Its working load capacity and service life under heavy load and other working conditions are one of the key indexes of mechanical design. In this paper, the surface fixation under heavy load of "lunar exploration project" spindle drill pipe and its supporting part-Mizhu shafting is used. Body film lubrication design and implementation for the application background, The failure process and interface mechanics mechanism of solid lubricating film commonly used on bearing steel surface under heavy load were investigated. This paper provides the basis for the structure and lubrication design of the bead shafting. The two-dimensional and three-dimensional interface mechanical analysis models of the solid film surface under the action of concentrated element force are established, and the complex variable function mirror image method is used. Two boundary conditions of free surface and continuous interface of solid films are used to realize different order image iterations. The recursive coefficients of each order image of solid films and substrates are calculated to satisfy the boundary conditions of surface and interface. Finally, the analytical solution of interfacial stress and deformation is obtained. By integrating the concentrated force, the two-dimensional and three-dimensional interface mechanics analysis models of the membrane base system under the synergistic action of normal and tangential distributed forces are obtained. In order to simplify the three-dimensional integration process, the interfacial stress and deformation solutions of the membrane base system are obtained directly by using the solution of transversely isotropic stress potential function, and the results are compared with that of the finite element method. This method has the same precision, faster speed and better adaptability to different working conditions. For the lamellar molybdenum disulfidemolybdenum disulfide MoS _ 2 film and hard brittle diamond-like carbon like carbon DLCL film, which are commonly used in high pair contact of mechanical parts, The friction and failure behavior of thin films varying with load was measured by ball disk friction and nano / micron scratch methods, the elastic properties of solid films and substrates were obtained by nano indentation test, and the interface mechanics calculation was performed. The law of interfacial stress response and the parameter change of failure process during the loading process of solid films are analyzed. The interlayer slippage of MoS2 thin films under low interfacial shear stress is analyzed. However, the flake spalling DLC films under high interfacial shear stress are characterized by tensile fracture at the contact back end under heavy load and dislocation failure at the front end of the films. The structural design and internal load analysis of the bead shaft system were carried out according to the load requirement of drill pipe. According to the failure characteristics of solid film and boundary parameters, the interfacial stress state of the film was calculated under the lubrication of molybdenum disulfide and diamond-like carbon film. The application performance of solid lubrication was tested by using the bead shafting simulation test platform.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TG174.4;TH117.2

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