共查询到17条相似文献,搜索用时 515 毫秒
1.
2.
3.
4.
非牛顿特性下冷挤压流体动力润滑模型的建立 总被引:1,自引:0,他引:1
应用磨擦学和金属塑性成形理论,对冷挤压工艺中的流体动力润滑机理进行了分析。针对冷挤压高压、大剪应变率工况下,润滑剂呈非牛顿特性的特点,运用Ostwald非牛顿体模型,分别建立了冷挤压非稳定流体动力润滑状态和稳定流体动力润滑状态的数学模型,并运用该模型对以蓖麻油作润滑剂的纯铝冷挤压进行了分析。计算结果揭示了冷挤压过程中,润滑油膜厚度及油膜压力的分布。 相似文献
5.
摩擦副表面物化特性对纳米级膜厚的影响 总被引:5,自引:0,他引:5
为研究固体表面物理化学特性对 nm级润滑膜厚度的影响 ,以铝、铬、钛和二氧化钛作为基体表面材料 ,采用NGY- 2型 nm级膜厚测量仪 ,对 136 0 4标准粘度液、添加有10 %十六酸乙酯的 136 0 4溶液和液体石蜡的膜厚进行了测量 ,并利用 Fourier红外分析仪对润滑剂在实验前后的成分变化进行了检测。红外光谱数据表明 ,不同基体下 ,润滑剂在实验前后的化学成分没有发生变化。膜厚测量结果发现 ,基体的表面物理化学性质对润滑膜厚度有较大影响 ,对基体Al,Cr,Ti,Ti O2 ,弹流润滑向薄膜润滑的转变的临界膜厚按基体表面能增大的顺序依次增大。该研究为处于薄膜润滑状态的润滑系统摩擦副的设计提供了理论基础 相似文献
6.
汽车覆盖件拉深成形过程中的摩擦研究 总被引:1,自引:0,他引:1
借助板料拉深成形性能实验测试系统,应用物理模拟的方法研究了覆盖件拉深 成形过程中磨擦与润滑的关系,并通过自行配置的油基润滑剂和水基润滑基研究了汽车覆盖件拉深成形过程中压边力与不同润滑状态的关系。由于水基润滑剂对压边力的敏感性,将水基润滑剂在不同压边力值条件下测试得到的磨擦系数进行了回归分析,建立起磨擦系数与压边力的实验回归方程。 相似文献
7.
在薄膜润滑的无限短径向轴承中,薄膜间隙和吸附层厚度对润滑剂的影响不可忽视.引用薄膜润滑的等效粘度模型推导无限短径向轴承的等效粘度计算模型以获得薄膜润滑无限短轴承的解析解,并运用该模型进行薄膜润滑条件下无限短径向滑动轴承的性能分析,确立了参数与轴承性能变化之间的关系,为工程实际计算提供了理论依据. 相似文献
8.
粘—塑性流体润滑失效研究—滑动问题 总被引:1,自引:0,他引:1
从润滑剂极限剪应力出发,以粘-塑性流体本构的线接触问题为例,从理论上分析了滑动问题中极限剪应力对润滑理论基本方程的改变,推出了滑动边界Reynolds方程以及为满足流量连续而存在的恒压区,对所得到的屈服条件下的润滑理论方程的分析和计算表明:当润滑膜的较大区域上剪应力达到极限值时,润滑膜的承载能力将大大降低。 相似文献
9.
润滑失效分析 总被引:2,自引:0,他引:2
黄平 《华南理工大学学报(自然科学版)》2002,30(11):95-100
介绍了笔者等人近年来在润滑失效方面的研究结果,通过对润滑剂非牛顿性,润滑剂温升和固体表面粗糙度对润滑失效的影响的研究,发现了固-液表面的边界滑移,推导了热本构方程,分析了固体材料粘弹性的影响,分析表明:(1)润滑剂的在固体表面会发生滑移,滑移将不再增加润滑剂的传动摩擦力,而且它将导致润滑膜的承载能力大大降低;(2)润滑剂内部的摩擦热导致的润滑膜的承载能力不会无限增大,当其增加到最大值后,会逐渐降低,从而导致润滑膜的破裂;(3)在实际变形下,表面粗糙和变形的耗时将引起润滑条件下的固体表面磨损。 相似文献
10.
研究了铝管拉伸摩擦润滑状态、铝管拉伸工艺润滑的特点及其对润滑剂的要求、配方和实验过程.作者研制的新型拉伸润滑剂解决了优良的润滑性能与拉伸铝管表面无光泽和污染的矛盾,在满足大变形拉伸过程工艺润滑的同时,可使所拉铝管获得光亮的退火表面. 相似文献
11.
Developments and unsolved problems in nano-lubrication 总被引:2,自引:0,他引:2
The main achievements in the area of nano liquid film, e.g. the distinction between different lubrication regimes, properties of thin film lubrication, the transition between liquid and solid state, ordered and disordered state, the failure of thin lubricant film, the equivalent viscosity and flowing characteristics of micro-fluid, the influence of solid surfaces on nano-lubrication, thin film lubrication of polymer, superlubricity, have been reviewed and some unsolved problems are discussed. 相似文献
12.
13.
ZHANG Chaohui LUO Jianbin HUANG Zhiqiang 《科学通报(英文版)》2005,50(22):2645-2649
It is an important concern to explore the properties and principles of lubrication at nano or molecular scale. For a long time, measurement apparatus for film thickness of thin film lubrication (TFL) at nano scale have been devised on the basis of superthin interferometry technique. Many experiments were carried out to study the lubrication principles of TFL by taking advantages of aforementioned techniques, in an attempt to unveil the mechanism of TFL. Comprehensive experiments were conducted to explore the distinctive characteristics of TFL. Results show that TFL is a distinctive lubrication state other than any known lubrication ones, and serves as a bridge between elastohydrodynamic lubrication (EHL) and boundary lubrication (BL). Two main influence factors of TFL are the solid surface effects and the molecular properties of the lubricant, whose combination effects result in alignment of liquid molecules near the solid surfaces and subsequently lubrication with ordered film emerged. Results of theoretical analysis considering microstructure are consistent with experimental outcomes, thus validating the proposed mechanism. 相似文献
14.
Under conditions of low speed, small viscosity and molecularly smooth tribo-surfaces, the behavior of lubricant film in the
nano scale is different from that in elastohydrodynamic lubrication (EHL) and boundary lubrication (BL). Due to the size effect,
long-range ordered structure of liquid crystal (LC) has great effects on the tribological properties and film-forming mechanism
of thin film in the nano scale. The technique of relative optical interference intensity (ROII) was used to investigate nano-tribological
properties when cholesteryl LCs are added to hexadecane. The results indicate that the practical film thickness of hexadecane
with liquid crystal is 3–5 times as large as that expected from EHL theory in the low speed region. The film thickness increases
with the enhancement in polarity and concentration of LC in hexadecane, and external DC voltage. The effective viscosity of
lubricant is related to the film thickness and the voltage and it varies from bulk viscosity to several times or tens of times
of bulk viscosity with reducing film thickness, and slowly rises with increasing external DC voltage and then trends to a
constant. The higher ordered degree of molecules close to solid surfaces gives rise to a thicker film. 相似文献
15.
Progresses and problems in nano-tribology 总被引:3,自引:0,他引:3
The recent development in the four areas of nano-tribology is analysed. They are micro and nano-friction and wear, mi-cro
and nano-tribological engineering. The research methods in nano-tribology and thin film lubrication in which five branches
are included: equivalent viscusity and flowing characteristics of micro fluid, the transition between ordered molecular film
and disordered one, the essence of matrix influence on thin film lubrication, the lubrication mechanism of high polymer lubricants
and the problem of superlubricity. Meanwhile, more than 35 problems are proposed which should be solved in the future. 相似文献
16.
为研究超薄润滑膜的摩擦特性和添加剂的影响 ,采用自制的表面力仪进行了润滑剂基础油和油性添加剂的薄膜流变实验。结果表明 :当膜厚减薄到纳米量级时 ,润滑油呈现非牛顿剪切响应 ,即剪切稀释现象 ,其等效粘度随着膜厚变薄而增加 ,并在某个临界膜厚处急剧上升。加入添加剂后 ,润滑油等效粘度降低 ,临界膜厚变小 ,说明薄膜流变特性与界面的摩擦状况有关。指出油性添加剂的功能在于形成摩擦系数小但厚度较薄的吸附层 ,与界于壁面间的润滑流体构成夹层结构 ,从而较好地解释了实验规律 相似文献
17.
采用本文设计的强迫润滑装置进行试验,测量出口钢丝表面润滑剂的附着量和温度,以及拉拔力与压力管长度和拉拔速度的关系,并和常规润滑拉拔进行了比较。通过试验和理论公式,给出了压力管较适宜的长度。 相似文献