查询词典 friction coefficient

The rule of dry sliding friction wear of vermicular iron was analyzed. The influence of working conditions, composition and structure on dry sliding friction characteristics was investigated, 3D morphologies of friction surfaces of vermicular iron and temperature characteristics of friction surface were discussed. The results showed that, compared with nodular and gray irons, vermicular iron has lowest wear rate, highest friction coefficient and lowest friction coefficient attenuation, so it is suitable to be as the material of braking device.

分析了蠕墨铸铁的干滑动摩擦磨损规律，研究了工况条件、成分、组织对蠕墨铸铁干滑动摩擦学特性的影响，探讨了蠕墨铸铁摩擦表面二维形貌与摩擦表面温度特性，结果表明：蠕墨铸铁与球墨铸铁和灰铸铁相比具有最低的磨损率和最高的摩擦系数与最低的摩擦系数衰减量，适合于作为制动器材料。

The friction performances of carbon face were investigated with an inertia friction tester. The torque curve of carbon face was ideal, the coefficient of static friction was lower than that of dynamic in 0.28 MPa, the friction coefficient of static and dynamic decreased with the braking pressure increasing. To the fiber face, the coefficient of dynamic friction of carbon face was more stable in cycle braking process, the wear rate was lower, and it was efficient to protect the couple plate not to be worn.

结果表明：碳质层的摩擦力矩在制动初期上升较快，中间过渡区平稳，尾部翘起较小；在制动压力小于0.28 MPa时静摩擦系数小于动摩擦系数，且动、静摩擦系数均随制动压力增加而减小；相对纤维层而言，采用碳质层摩擦时摩擦力矩曲线形态更好，连续制动时摩擦系数波动较小，磨损率低且能够有效保护偶件，是1种静/动摩擦系数比较低且适用于高载荷工况条件下使用的摩擦材料。

The results indicate that as the value of fractal dimension is increased, the interfacial static friction coefficient first increases and then decreases; the interfacial static friction coefficient decreases as the fractal roughness parameter increases; while the inter-facial static friction coefficient increases as the material property or total normal load increases; the curve of static friction coefficient versus dimensionless total normal load is convex when the fractal dimension becomes smaller or fractal roughness parameter is larger or material property becomes smaller.

研究结果表明：界面的静摩擦因数首先随分形维数的增加而增加，然后随分形维数的增加而减小；界面的静摩擦因数随分形粗糙度参数的增加而减小，但随材料特性的增加而增加，也随总法向载荷的增加而增加；当分形维数较小或分形粗糙度参数较大或材料特性较小时，静摩擦因数－量纲一的总法向载荷曲线为凸弧。

In order to reasonably depict four basic problems with friction, one Coulomb friction new form in first Kirchhoff stress is proposed to deal with finite deformation problems, other Coulomb friction form in incremental mode to elastoplastic flow theory; Hilbert function spaces concerning elastoplastical problems with friction are established, so it makes all operations and calculations in the treatise standardized within the scope of reasonably topologic structure; In view of functional extremum, the equivalence between generalized variational inequalities principles in elastoplasticity with friction and corresponding basic problems are testified by inducing Lagrangian multipliers, so it provides a rationally theoretical basis for numerical methods in elastoplasticity with friction; From the viewpoint of variational inequality, the theory of generalized variational inequalities in elasticity and elastoplasticity with frictional constraint is studied, and the uniqueness and existence of the solution of FEM is proofed under the proposed conditions of stress compatibility, and them FEM approximation and a discrete solution are discussed; Based on the principles of generalized variational inequalities in elastoplasticity with friction, direct generalized variational inequalities methods is pretended, which is a natural generalization and development of direct variational methods; Using generalized variational inequalities methods, some examples in metal forming including plane deformation, upset and extrusion are analyzed and the results prove that all the theories and methods in the paper are right, feasible, accurate and advanced.

主要内容有：为了合理地描述金属塑性成形中摩擦约束弹性、弹塑性基本问题，提出和研究了有限变形下以Kirchhoff第一应力表示的Coulomb摩擦定律形式和弹塑性流动理论下以增量形式表示的Coulomb摩擦定律表示形式；系统建立了摩擦约束弹塑性问题的Hilbert函数空间，使本文规范在一个具有合理的代数拓扑结构内进行一切操作和运算；利用Lagrange乘子，从泛函极值的角度系统地阐述和论证了一系列摩擦约束弹性、弹塑性广义变分不等原理与相应的实际问题之间的等价性，它为处理摩擦约束的弹塑性力学数值方法提供了合理的理论基础；从变分不等式的角度出发，阐述了对应于摩擦约束弹性、弹塑性问题的广义变分不等式理论，首次提出了在应力相容性条件下，它的有限元解具有存在唯一性，进而讨论了其有限元近似及离散解法；基于摩擦约束弹塑性广义变分不等式原理，首次提出了直接广义变分不等式方法，这一方法是直接变分法的合理推广和发展；利用直接广义变分不等式方法对金属压力加工中的平面变形问题、镦粗、挤压等塑性成形问题进行了分析计算，验证了该理论和数值算法的正确性、实用性、精确性和优越性。

Friction are many ways to fitness, with a dry towel friction body, known as "dry cloth friction"; with a soft brush friction, known as "brush friction"; with a cold towel wrung friction is called "cold-water friction"; also can be used "hand-rub the Law" and so on.

磨擦健身的方法很多，用干毛巾磨擦全身，叫作&干布磨擦&；用柔软的刷子磨擦，称为&刷子磨擦&；用拧干的冷毛巾磨擦叫&冷水磨擦&；此外还可以采用&手擦法&等等。

The law of factors' affecting degree, which influences the parameters between geogrids and soils in the pulling-out procedure, is obtained. With the concept of 'equivalent pull-out displacement' brought forward, the whole process of pull out tests is divided into two process-" main process (when x 1.0)" and "residual process (when x 1.0)", and three stages-static friction resistance stage, slip friction resistance stage, and residual friction resistance stage.2 The value of friction coefficient between reinforcement and soil varies with their definitions of friction, but each factor' s affecting degree influencing friction pa

将模糊控制理论引入了岩土工程过程分析，考虑影响因素影响程度的变化及其规律，提出了一套可供岩土工程过程分析中参数选择的分析方法，并在筋土界面相互作用参数选取的拉拔试验过程控制中获得实施，为应用有限元法对加筋土结构进行过程中南大学博士论文摘要分析提供了参数选择的新方法；将模糊聚类分析方法应用于加筋土陡边坡状态评定，并提出侧向位移可作为加筋土边坡状态评定的量化指标，而不同类型边坡的侧向位移允许控制值可仿效此法结合工程经验确定。

The author also studies the relationship between the maximum friction coefficient, optimum slip ratio, friction coefficent with locked wheels and three parameters in friction coefficient function of slip ratio, and three fit functions derived from experimental analysis, maximum friction coeffient, optimum slip ratio and friction coefficent v~ ith locked wheels, of aircraft speed.

利用试验数据研究了最佳滑移率、结合系数最大值和机轮抱死时的结合系数随飞机速度的变化规律。两者联系在一起，便得到了结合系数随飞机速度和滑移率的变化规律。它是本文的创新点之三。

The friction performances of carbon face were investigated with an inertia friction tester.The torque curve of carbon face was ideal,the coefficient of static friction was lower than that of dynamic in 0.28 MPa,the friction coefficient of static and dynamic decreased with the braking pressure increasing.To the fiber face,the coefficient of dynamic fric...

结果表明：碳质层的摩擦力矩在制动初期上升较快，中间过渡区平稳，尾部翘起较小；在制动压力小于0.28 MPa时静摩擦系数小于动摩擦系数，且动、静摩擦系数均随制动压力增加而减小；相对纤维层而言，采用碳质层摩擦时摩擦力矩曲线形态更好，连续制动时摩擦系数波动较小，磨损率低且能够有效保护偶件，是1种静/动摩擦系数比较低且适用于高载荷工况条件下使用的摩擦材料。

The results show that when the porosity of sample was higher, compressure rate was higher and resilience rate was lower, however resilient rate of sample with higher porosity were increased notably when pressure was increased, and it tended to accord with of sample with lower porosity. The friction coefficient was higher when porosity of paper-based friction material was higher, and the friction coefficient tended to reduce and stabilize when braking pressure was increased. The friction coefficient of sample with high porosity tended to reduce and stabilize in continuous braking cycles.

结果表明：在相同载荷下，随着孔隙率增大，材料的压缩率增加而回弹率降低，随着载荷增加，高孔隙率材料的回弹率先明显增大，而后趋于稳定；在相同比压和转速下，孔隙率越高，材料的摩擦系数越大，随着比压增加，孔隙率高的材料摩擦系数逐渐降低，且不同孔隙率材料的摩擦系数逐渐趋于一致；在连续循环制动时，高孔隙率材料的摩擦系数逐渐降低并趋于稳定。

For the first patern, elastic dynamics is adopted to study the steady state rolling contact, elastic dynamics incorporating with rigid dynamics is adopted to study the non-steady state. For the steady state, the analytical solution is obtained, and for the non-steady state, the variational formulation to solve the problem numerically is derived For the later patern, the function type friction coefficient is introduced. On the basis of the quasi-stastic theories of constant friction coefficients, both the exact theory and the simplified theory of the function type friction coefficient are established, the computer programms for both the theories are also made out. Using the function type friction coefficient, Shen-Hedrick-Elkins theory's application range is extended to large creepage .

对于速度对接触体力学特性的影响，本文采用弹性动力学方法和弹性动力学与刚体动力学相结合的方法分别对稳态和非稳态两种情况进行了研究，得到了稳态情况的解析解，给出了对非稳态情况进行数值求解的变分公式；对于速度对相关物理量的影响，本文主要讨论了速度对摩擦系数的影响，在滚动接触准静态理论的基础上引进了函数型摩擦系数，建立了函数型摩擦系数的滚动接触准静态精确理论和简化理论，并分别编制了相关的计算程序，还用函数型摩擦系数将简便的Shen-Hedrick-Elkins理论的适用范围扩展到大蠕滑区。

The circulation, consumption and reproduction of the trilogy have not only testified to its historical significance and literariness, but also invested it with new meanings.

该三部曲的流通、消费与再生产不仅验证了其历史意义及文学性，而切还赋予它以新的意义。

If he thought that he could buy me off, he would be wrong.

如果他认为他可以收买我，那他就大错特错了。