粗糙接触表面微滑移诱发的磨损与能量损耗及其动态演化

Microslip, which has been revealed in rough contacting surface of fastened connecting part in many high speed and precision mechanical systems, is one important factor that decreases the vibration and increases the dynamic performance of mechanical system. The contacting mechanics between the rough interfaces have not been sufficiently investigated since only the two-dimensional Coulomb friction model, incorporating only piece-wise nonlinearity, has been utilized currently and thus cannot describe the real three-dimensional frictional behavior accurately on the contacting interface. The rough surface generation scheme to represent the engineering oriented contacting interface will be studied first in this project. The normal tractions and tangential tractions distribution will be solved for the contacting interfaces, which is enforced by time-varying normal and tangential external loads. The multi-node three-dimensional microslip model will be established and a high accuracy numerical scheme will be proposed to provide the responses of the multi-node model. The microslip phenomenon, wear and energy dissipation induced by the microslip inside the asperity contacting regions of rough contacting surface and will be investigated. The variations of the surface geometry caused by the accumulated wear are introduced to analyze the dynamic evolution of microslip, wear and energy dissipation behavior. The experiments incorporating rough contacting surfaces are established to examine the relationship between wear, energy dissipation and surface roughness and magnitude of excitations and thus to validate the theoretical research results of the project. It’s anticipated that an in-depth understanding of microslip, wear and energy dissipation will be proposed and the important factor that influent contact behavior will be revealed. The methods and approaches that can optimize the contact behavior will also been acquired and thus provide theoretical support for product design for mechanical systems.

高速、精密机械系统紧固联接部位粗糙接触表面的微滑移是减小系统振动、提高动态服役性能的重要因素。目前对于微滑移的研究采用二维滑移模型，并不能真实描述粗糙接触表面的摩擦接触行为，影响对其深入认识和准确理解。为此，本课题首先研究三维粗糙接触表面数字化表征方法；求解法向和切向外部激励作用下三维粗糙接触表面正压力和剪切力的分布规律；建立粗糙接触表面的三维微滑移多结点模型，研究多结点模型的求解算法，分析接触区域内的微滑移及其诱发的磨损和能量损耗；引入累积磨损对粗糙表面几何形貌特征的影响，研究粗糙接触表面微滑移、磨损和能量损耗行为的动态演化规律。搭建粗糙接触表面实验系统，研究磨损、能量损耗随表面粗糙度和载荷的变化规律，验证课题理论研究的正确性。预期通过课题研究深入了解微滑移、磨损与能量损耗的发生机理及其动态演化规律，揭示影响粗糙表面的接触行为关键因素，寻求优化接触行为的方法与途径。

粗糙接触表面发生的摩擦行为对机械系统的载荷传递和动态响应都会产生重要影响，而接触界面之间的摩擦运动引发部分振动能量的耗散能有效降低系统振动。但是，接触行为受到几何形貌、预紧力、接触尺寸等因素的影响，呈现出复杂的非线性行为，导致接触界面间的能量损耗、磨损等问题一直未得到很好的解决。为此，本课题在已有的平面二维库伦摩擦力系统的封闭解的基础上，考虑了结点正压力、切向载荷及摩擦阻力，建立了二维库伦摩擦力系统动态响应和准静态响应的算法，实现了对含有滑移、粘滞、分离状态的单结点运动响应的准确预测，求解了法向和切向外部激励作用下三维粗糙接触表面正压力和剪切力的分布规律。针对求解过程中特殊情况下出现的病态问题，提出了基于角度增量的平面库伦摩擦力系统求解算法，将隐式求解转变为显式求解，提高算法求解稳定性和求解精度以及每一迭代步的计算效率，实现了对准确滑移/粘附转换时刻的精确计算。利用MB分形模型，开展了三维粗糙接触表面数字化表征，引入累积磨损对粗糙表面几何形貌特征的影响，建立了粗糙接触表面的多结点三维微滑移模型，研究多结点模型的求解算法，分析接触区域内的微滑移及其诱发的磨损和能量损耗，研究粗糙接触表面微滑移、磨损和能量损耗行为的动态演化规律。