查询词典 threshold friction

Simulation of micro-milling process is conducted using finite element method. During modeling, the Johnson-Cook's coupled thermal-mechanical model was employed as workpiece material model, the Johnson-Cook s shear failure principle was adopted as work piece failure principle, and the coupled thermal-mechanical hexahedron strain hybrid modules and adaptive grid were used to remesh the workpiece's elements. The friction between the tool and workpiece obeys the amended coulomb's law that combines with the sliding friction and the adhesive friction.

采用有限元方法对微细铣削过程进行模拟，采用Johnson-Cook热力耦合模型作为工件材料模型，采用Johnson-Cook的剪切失效法则作为工件材料的失效准则，采用热力耦合平面应变杂交单元并使用自适应网格技术进行网格划分，刀具与工件间的摩擦采用滑动摩擦区和粘着摩擦区相结合的修正库仑定律。

The results under the oil lubricate friction conditions were similar with those under the dry friction conditions. The wear mechanism of 3Cr13 matrix alloy was micro-cutting and distorting wear. For the composites with a low fraction of TiC particle, distorting wear dominated and cutting was partly operating. For the composites with a high fraction of TiC particle, stress fatigue wear and wear of hard phase decohesion has occurred, but the main wear mechanism was still distorting wear. When the wear experiments were performed under the oil lubricate friction conditions, the main wear mechanism has became to abrasive wear and fatigue wear for the composites with the low TiC fraction, and fatigue wear would be to dominate for the composites with the high TiC fraction. There were similar wear mechanisms in H13 and 1Cr18Ni9 matrix composites.

在干摩擦条件下，3Cr13基体合金的磨损机理为显微切削和变形磨损；低体积分数的复合材料磨损机制以变形磨损为主，兼有少量的切削磨损机制；高体积分数的复合材料磨损机制以变形磨损为主，兼有应力疲劳磨损和脆性相剥落磨损；在油润滑摩擦条件下，3Cr13基体合金的磨损以磨粒磨损为主；低体积分数的复合材料磨损为磨粒磨损和疲劳磨损；高体积分数的复合材料磨损以疲劳磨损为主。H13、1Cr18Ni9基体及其复合材料的磨损机制类似于3Cr13基体及其相同体积分数的复合材料。

Generally, its operating condition is under the low-speed and thin oil lubrication, so the viscous friction was usually neglected and the friction torque caused by main influencing factors of elastic hysteresis in rolling, spin of rolling element and sliding friction on contact zone were considered.

低速灵敏球轴承小而稳定的启动力矩和动态力矩对于导航系统的姿态控制至关重要，其工况通常是低速稀油润滑，黏性摩擦被忽略而重点推导接触区因弹性滞后、自旋及差动滑动引起的摩擦力矩。

At present, although finite element methods is a kind of effective measures in analyzing metal plastically forming problems with friction, dynamic friction in the process of metal forming is substituted with static friction and constant frictional force as one of independent constraint conditions is transposed to equivalent node-load or FEM unit is divided into contact unit and inner unit in numerous studys and applications, so that it result in relative bad accuracy and awkward operation. These defects mostly attribute to the fact that FEM bases on the variational equality principles, however frictional constraint will actually result in variational inequality energy functional.

目前，应用于分析金属塑性成形的有限元法是一种有效的处理摩擦效应的定量计算方法，但是许多应用和研究是用常摩擦来代替金属塑性成形过程中的动态摩擦；把常摩擦力作为单独的约束条件移置到等效结点载荷上或把有限元单元划分成接触单元和内单元，这些将导致解的精度相对不高及实际操作不方便等一系列问题，产生这些不足的重要原因之一在于它的理论基础是变分等式原理。

For nonlinear friction force in hydraulic position tracking system, partition compensation is to solve the problem of large approximation error caused by non-smooth characteristic of friction when the whole friction is compensated by one fuzzy neural network.

针对液压位置跟踪系统中的非线性摩擦力，提出对摩擦力模型的不同分量分别进行补偿的分部补偿算法，以解决用模糊神经网络对摩擦力整体进行补偿时，因摩擦力非光滑特性引起较大逼近误差的问题。

We analyze the principle of stick-slip motion deeply. From foregoing analysis a result was made that dry friction is the main factor in influencing low speed capability of electro-hydraulic servo system. Dry friction must be compensated for improving the low speed performance. Then a nonlinear model with friction is set up and control methods is discussed.

深入分析了汽轮发电机转速不稳定的原因是由于电液伺服系统在低速区性能不稳定，而影响电液伺服系统低速性能的主要因素是干摩擦，要提高电液伺服系统的低速性能必须对摩擦力进行补偿。

After analyzing the general principle of friction drive, this paper studies the kinematics and the dynamics of twist-roller friction drive deeply, and discovers the changing law of friction direction.

本文在分析了摩擦传动一般原理的基础之后，深入研究了扭轮摩擦传动系统的运动学、动力学问题。

The index of slipping friction work is incompatible with that of shock intensity. In order to form an integrative optimization between shock intensity and slipping friction work, different gear shift control strategy have been made to find a compromise between shock intensity and slipping friction work according to different work condition of E.T.

滑磨功和冲击度这两个指标相互制约，因而为了达到综合最优，针对电动变速驱动单元不同工作状况，制定了不同的换档控制策略来达到冲击度和滑磨功协调最优。

The mode of the friction saw cutting has been founded and the theory of that one has been put forward according to analysing the process of friction saw cutting, which make use of friction and extrusion to increase temperature of the area of work cutting and make the hardness and strength of work reduce obviously.

通过对摩擦锯切过程的分析，建立摩擦锯切模型，提出了摩擦锯切的原理，主要是利用挤压变形和摩擦，提高工件切削区的温度，使工件的强度和硬度显著下降，同时，设法保持刀具的温度在300℃以下，使硬度保持不变，从而实现了刀具硬度与工件硬度比的大量增加，完成超高速切削。

However, POM/PEO interfibrillar segregation and the interspherilute segregation crystalline structures seem unfavourable for the toughness of the blends.5. PEO can improve the friction and wear properties of POM/PEO blends because PEO in the blend melts during friction and transfers to the friction surface, forming a lubricative layer.

磨痕宽度则先减小后增加，这是因为随PEO含量增加，其结晶结构发生了变化，无定形PEO与POM微纤晶穿插有利于减小磨痕宽度。6。

He studied their excrement for evidence of livestock hair.

他为家畜毛的证据研究他们的粪便。

Loneliness is not grounds for deportation, deportation of the people are not all lonely people.

寂寞也不是放逐的理由，放逐的人也并不都是孤独的人。