考虑表面力的低弹性模量聚合物材料接触计算方法  

Contact calculation method for low-elastic-modulus polymer materials considering surface force

作　　者：赵明波 张晨辉[1] 郭丹[1] ZHAO Mingbo;ZHANG Chenhui;GUO Dan(State Key Laboratory of Tribology in Advanced Equipment,Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学机械工程系,高端装备界面科学与技术全国重点实验室,北京100084

出　　处：《清华大学学报(自然科学版)》2025年第2期392-403,共12页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金杰青项目(51925506);国家自然科学基金重点项目(52335004)。

摘　　要：聚合物材料在摩擦设计上具有广泛的应用。对聚合物进行改性,增强聚合物表面与水合离子的结合能力,利用水合效应减小摩擦是聚合物摩擦副减摩设计的重要手段。但聚合物材料的弹性模量通常比较低,对这种低弹性模量材料在水合效应作用下的接触情况,目前还没有构建出很好的数值模型。该文构建了考虑水合效应的低弹性模量聚合物材料接触数值模型,分析了表面力和弹性模量对接触状态的影响。发现低弹性模量材料接触压力小,接触区域的各处分布压力可能完全由水合层承担,形成纳米级间隙。研究还表明,表面形貌对低弹性模量下考虑表面力的接触计算结果影响较小,对高弹性模量下的则影响较大。此外,弹性模量对模型收敛性有显著影响,低模量情况下收敛难度显著增加。该成果为后续聚合物材料在表面力作用下的混合润滑数值计算研究奠定了基础。[Objective]Polymer materials exhibit promising prospects in various applications,such as ship bearings and artificial joints,due to their low density as well as high toughness,corrosion resistance,and foreign-matter tolerance.However,in engineering applications,there is often a need to reduce friction.Modifying polymers to enhance their surface binding capacity with hydrated ions and utilizing the hydration effect to reduce friction,represents an important strategy in the tribological design of polymer friction pairs. Polymer materials typically possess a low elastic modulus, and the hydrationeffect introduces nonlinearity into iterative algorithms. Consequently, a robust numerical model for simulating the contactbehavior of such low-elastic-modulus materials under the hydration effect remains elusive. [Methods] This paper presents anumerical model for simulating the contact behavior of low-elastic-modulus polymer materials under the hydration effect.Taking ultra-high-molecular-weight polyethylene (UHMWPE) and sapphire as an example, a rough surface with aGaussian-distributed topography is constructed to analyze the influence of surface forces and material elastic modulus onmaterial contact behavior. [Results] The findings reveal that low-elastic-modulus materials exhibit low contact pressures,with pressure distribution across the contact area potentially fully supported by the hydration layer, resulting in the formationof nanoscale gaps. Calculations indicate that when the maximum pressure in the contact area is less than the maximumrepulsive pressure provided by surface forces, the two surfaces can be completely separated. Conversely, when a part of thepressure in the contact area exceeds the maximum repulsive force, partial separation occurs, with regions where the contactpressure is less than the maximum surface force remaining fully separated. A low elastic modulus promotes the reduction ofpressure in the contact area, facilitating surface separation and friction reduction. This study shows that surface topo

关 键 词：聚合物材料 水合效应 弹性模量 表面力 接触计算模型 

分 类 号：TH117.2[机械工程—机械设计及理论] TH145.4[一般工业技术—材料科学与工程]