外文翻译《轮辐柔性变形效果和滚动接触的潜变力追踪》
毕业设计（外文翻译）题目：
Effects of structure elastic deformations of and track on creep forces of wheel/rail in rolling contact
Effects of structure elastic deformations of wheel set and track on creep forces of wheel/rail in rolling contact
Xuesong Jin, Pingbo Wu, Zefeng Wen
National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031, PR China
Abstract
In this paper the mechanism of effects of structure elastic deformations of bodies in rolling contact on rolling contact performance is briefly analyzed. Effects of structure deformations of wheel set and track on the creep forces of wheel and rail are investigated in detail. General structure elastic deformations of wheel set and track are previously analyzed with finite element method, and the relations, which express the structure elastic deformations and the corresponding loads in the rolling direction and the lateral direction of wheel set, respectively, are obtained. Using the relations, we calculate the influence coefficients of tangent contact of wheel and rail. The influence coefficients stand for the occurring of the structure elastic deformations due to the traction of unit density on a small rectangular area in the contact area of wheel/rail. They are used to revise some of the influence coefficients obtained with the formula of Bossinesq and Cerruti in Kalker’s theo ry of three-dimensional elastic bodies in rolling contact with non-Hertzian form. In the analysis of the creep forces, the modified theory of Kalker is employed. The numerical results obtained show a great influence exerted by structure elastic deformations of wheel set and track upon the creep forces.
? 2002 Elsevier Science B.V. All rights reserved.
Keywords: Wheel/rail; Rolling contact; Creep force; Structure elastic deformation
1. Introduction
During running of a train on track the fierce action between wheel set and rails causes large elastic deformations of structure of wheel set and track. The large structure deformations greatly affect performances of wheels and rails in rolling contact, such as creep forces, corrugation [1–3], adhesion, rolling contact fatigue, noise [4,5] and derailment [6]. So far rolling contact theories widely used in the analysis of creep forces of wheel/rail are based on an assumption of elastic half
space [7–12]. In other words, the relations between the elastic deformations and the traction in a contact patch of wheel/rail can be expressed with the formula of Bossinesq and Cerruti in the theories. In practice, when a wheel set is moving on track, the elastic deformations in the contact patch are larger than those calculated with the present theories of rolling contact. It is because the flexibility of wheel set/rail is much larger than that of elastic half space. Structure elastic deformations (SED) of wheel set/rail caused by the corresponding loads are shown in Figs. 1 and 2. The bending deformation of wheel set shown in Fig. 1a is mainly caused by vertical dynamic loads of vehicle and wheel set/rail. The torsional deformation of wheel set described in Fig. 1b is produced due to the action of longitudinal creep forces between wheels and rails. The oblique bending deformation of wheel set shown in Fig. 1c and the turnover deformation of rail shown in Fig.
2 are mainly caused by lateral dynamic loads of vehicle and wheel set/rail. The torsional deformations with the same direction of rotation around the axle of wheel set (see Fig. 1d), available for locomotive, are mainly caused by traction on the contact patch of wheel/rail and driving torque of motor. Up to now very few published papers have discussions on the effects of the SED on creep ages and creep forces between wheel set and track in rolling contact.
In fact, the SED of wheel set/rail mentioned above runs low the normal and tangential contact stiffness of wheel/rail. The normal contact stiffness of wheel/rail is mainly lowed by the subsidence of track. The normal contact stiffness lowed doesn’t affect the normal pressure on the contact area much. The lowed tangential contact stiffness affects the status of stick/slip areas and the traction in the contact area greatly. If the effects of the SED on the rolling contact are taken into account in analysis of rolling contact of wheel/rail, the total slip of a pair of contacting particles in a contact area is different from that calculated with the present rolling contact theories. The total slip of all the contacting particles and the friction work are smaller than those obtained under
condition that the SED is ignored in the analysis of creep forces of wheel/rail. Also the ratio of stick/slip areas in a contact area is larger than that without consideration of the effects of the SED.
In this paper the mechanism of effects of structure elastic deformations of bodies in rolling contact on rolling contact performance is briefly analyzed, and Kalker’s theoretical model of three-dimensional elastic bodies in rolling contact with non-Hertzian form is employed to analyze the creep forces between wheel set and track. In the numerical analysis the selected wheel set and rail are, respectively, a freight-car wheel set of conical profile, Chi na “TB”, and steel rail of 60 kg/m. Finite element method is used to determine the SED of them. According to the relations of the SED and the corresponding loads obtained with FEM, the influence coefficients expressing elastic displacements of the wheel set and rail produced by unit density traction acting on the contact area of wheel/rail are determined. The influence coefficients are used to replace some of the influence coeffi- cients calculated
with the formula of Bossinesq and Cerruti in Kalker’s theor y. The effect of the bending deformation of wheel set shown in Fig. 1a and the crossed influences among the structure elastic deformations of wheel set and rail are neglected in the study. The numerical results obtained show marked differences between the creep forces of wheel set/rail under two kinds of the conditions that effects of the SED are taken into consideration and neglected.
2. Mechanism of reduced contact stiffness increasing the stick/slip ratio of contact area
In order to make better understanding of effects of the SED of wheel set/track on rolling contact of wheel/rail it is necessary that we briefly explain the mechanism of reduced contact stiffness increasing the ratio of stick/slip area in a contact area under the condition of unsaturated creep-force. Generally the total slip between a pair of contact particles in a contact area contains the rigid slip, the local elastic deformation in a contact area and the SED. Fig. 3a describes the status of a pair of the contact particles, A1 and A2, of rolling contact bodies and without elastic deformation. The lines, A1A_1 and A2A_2 in Fig. 3a, are marked in order to make a good understanding of the description. After the deformations of the bodies take place, the positions and deformations of lines, A1A_1 and A2A_2, are shown in Fig. 3b. The displacement difference, w1, between the two dash lines in Fig. 3b is caused by the rigid motions of the bodies and (rolling or shift). The local elastic deformations of points, A1 and A2, are indicated by u11 and u21, which are determined with some of the present theories of rolling contact based on the assumption of elastic-half space, they make the difference of elastic displacement between point A1 and point A2, u1 = u11 ?u21. If the effects of structure elastic
deformations of bodies and are neglected the total slip between points, A1 and A2, can read as: S1 = w1 ?u1 = w1 ?(u11 ?u21) (1) The structure elastic deformations of bodies and are mainly caused by traction, p and p_ acting on the contact patch and the other boundary conditions of bodies and , they make lines, A1A_1 and A2A_2 generate rigid motions independent of the local coordinates (ox1x3, see Fig. 3a) in the contact area. The u10 and u20 are used to express the displacements of point A1 and point A2, respectively, due to the structure elastic deformations. At any loading step they can be treated as constants with respect to the local coordinates for prescribed boundary conditions and geometry of bodies and . The displacement difference between point A1 and point A2, due to u10 and u20, should be u0 = u10 ?u20. So under the condition of considering the structural elastic deformations of bodies and , the total slip between points, A1 and A2, can be written as: S?1 = w1 ?u1 ?u0 (2) It is obvious that S1 and S?1 are different. The traction (or creep-force) between a pair of contact particles depends on S1 (or S?1 ) greatly. When |S1| > 0 (or |S?1 | > 0) the pair of contact particles is in slip and the traction gets into saturation. In the situation, a ccording to Coulomb’s friction law the tractions of the above two conditions are same if the
same frictional coefficients and the normal pressures are assumed. So the contribution of the traction to u1 is also same under the two conditions. If |S1| = |S?1 | > 0, |w1| in (2) has to be larger than that in (1). Namely the pairs of contact particles without the effect of u0 get into the slip situation faster than that with the effect of u0. Correspondingly the whole contact area without the effect of u0 gets into the slip situation fast than that with the effect of u0. Therefore, the ratios of stick/slip areas and the total traction on contact areas for two kinds of the conditions discussed above are different, they are simply described with Fig. 4a and b. Fig. 4a shows the situation of stick/slip areas. Sign in Fig. 4a indicates the case without considering the effect of u0 and indicates that with the effect of u0. Fig. 4b expresses a relationship law between the total tangent traction F1 of a contact area and the creep age w1 of the bodies. Signs and in Fig. 4b have the same meaning as those in Fig. 4a. From Fig. 4b it is known that the tangent traction F1 reaches its maximum F1max at w1 = w_1 without considering the effect of u0 and F1 reaches its maximum F1max at w1 = w_1 with considering the effect of u0, and w_1 < w__ 1 . u0 depends mainly on the SED of the bodies and the traction on the contact area. The large SED causes large u0 and the small contact stiffness between the two bodies in rolling contact. That is why the reduced contact stiffness increases the ratio of stick/slip area of a contact area and decreases the total tangent traction under the condition of the contact area without full-slip.
3. Calculation of structure deformation of wheel set/rail
In order to calculate the SED described in Fig. 1b–d, and Fig. 2, discretization of the wheel set and the rail is made. Their schemes of FEM mesh are shown in Figs. 5, 7 and 9. It is assumed that the materials of the wheel set and rail have the same physical properties. Shear modulus: G = 82,000 N/mm2, Poisson ratio: μ= 0.28. Fig.
5 is used to determine the torsional deformation of the wheel set. Since, it is symmetrical about the center of wheel set (see Fig. 1b), a half of the wheel set is selected for analysis. The cutting cross section of the wheel set is fixed, as shown in Fig. 5a. Loads are applied to the tread of the wheel set in the circumferential direction, on different rolling circles of the wheel. The positions of loading are, respectively, 31.6, 40.8 and 60.0 mm, measured from the inner side of the wheel. Fig.
6 indicates the torsional deformations versus loads in the longitudinal direction. They are all linear with loads, and very close for the different points of loading. The effect of the loads on the deformation of direction of y-axis, shown
in Fig. 5a, is neglected.
Parameters of contact geometry of wheel set/rail to be used in the latter analysis read as:
ri =ri(y,ψ)
δi = δi(y,ψ)
?i = ?i(y,ψ)
ai = ai(y,ψ)
hi = hi(y,ψ)
z = z(y,ψ)
φ= φ(y, ψ) (3)
where i = 1, 2 stand for the left and right side w
heels/rails, respectively. The parameters in (3) are defined in detail in the Nomenclature of the present paper.We define that y > 0
when the wheel set shifts towards the left side of track and ψ > 0 if it is inclined, in the clockwise direction, between the axis of wheel set and the lateral direction of track pointing to the left side. The parameters depend on the profiles of wheel and rail, y and ψ. But if profiles of wheel and rail are prescribed they mainly depend on y [7]. Detailed discussion on the numerical method is given in [7,8] and results of contact geometry of wheel/rail.
When a wheel set is moving on a tangent track the rigid creep ages of wheel set and rails read as [8]:
[7]
[8]
where i = 1, 2, it has the same meaning as subscript i in (3). The undefined parameters in (4) can be seen in the Nomenclature. It is obvious that the creep ages depend on not only the parameters of contact geometry, but also the status of wheel set motion. Since the variation of the parameters of contact geometry depend mainly on y with prescribed profiles of wheel/rail some of their derivatives with respect to time can be written as
Putting (5) into (4), we obtain:
In the calculation of contact geometry and creep age of wheel/rail, the large ranges of the yaw angle and lateral displacement of wheel set are selected in order to make the creep age and contact angle of wheel/rail obtained include the situations producing in the field as completely as possible. So we select y = 0, 1, 2, 3, . . . , 10 mm, ψ= 0.0, 0.1, 0.2, 0.3, . . . , 1.0?, ˙ y/v = 0, 0.005 and r0 ˙ ψ/v = 0, 0.001. ?ri?y, ?φ/?y and ??i/?y are calculated with center difference method and the numerical results of ri , φand ?i versus y. l0 = 746.5mm, r0 = https://www.360docs.net/doc/bd12528003.html,ing the ranges of y, ψ, ˙ y/v and r0 ˙ ψ/v selected above we obtain that ξi 1 ranges from ?0.0034 to 0.0034, ξi 2 ranges from ?0.03 to 0.03, ξi 3 ranges from ?0.00013 to 0.00013 (mm?1), and contact angle δi is from to 2.88 to 55.83?. Due to length limitation of paper the detailed numerical results of creep age and contact geometry are not shown in this paper.
4. Conclusion
(1) The mechanism of effects of structure elastic deformation of the bodies in rolling contact on rolling contact performance is briefly analyzed. It is understood that the reduced contact stiffness of contacting bodies increases the stick/slip area of a contact area under the condition that the contact area is not in full-slip situation.
(2) Kalker’s theoretical model of three-dimensional elastic bodies in rolling contact with non-Hertzian form is employed to analyze the creep forces between wheel set and track. In the analysis, finite element method is used to determine the influence coefficients expressing elastic displacements of wheel set/rail produced by unit traction acting on each rectangular element, which
are used to replace some of the influence coefficients calculated with the formula of Bossinesq and Cerruti in Kalker’s theory. The numerical results obtained show the differences of the creep forces of wheel set/rail under two kinds of conditions that effects of structure elastic deformations of wheel set/rail are taken into consideration and neglected.
(3) The structure elastic deformations of wheel set and track run low the contact stiffness of wheel set and track, and reduce the creep forces between wheel set and track remarkably under the conditions of unsaturated creep force. Therefore, the situation is advantageous to the reduction of the wear, rolling contact fatigue of wheel and rail.
(4) In the study the effect of the bending deformation of wheel set shown in Fig. 1a is neglected, and the crossed influence coefficients AIiJj(i _= j ; i, j = 1, 2) are
not revised. So, the accuracy of the numerical results obtained is lowed. In addition, when the lateral displacement of center of the wheel set, y > 10mm, the flange action takes place. In such situation the contact angle is very large and the component of the normal load in the lateral direction is very large. The large lateral force causes track and wheel set to produce large structure deformations, which affect the parameters of contact geometry of wheel/rail and the rigid creep ages. Therefore, the rigid creep ages, the creep forces, the parameters of contact geometry, the SED and the motion of wheel set have a great influence upon each other. It is necessary that they are synthetically put into consideration in the analysis. Numerical results of them can be obtained with an alternative iterative method. Probably conformal contact or two-point contact between wheel and rail take place during the action of flange. Such phenomenon of wheel set and rails in rolling contact is very complicated, and can be analyzed with a new theory of rolling contact, which may be a FEM model including effects of structure deformations and all boundary conditions of wheel set and track in the near future.
This work was supported by the Natural Science Foundation Committee of China that grant the key research project: “Corrugation of Contact Surface of Wheel and Rail and Rolling Contact Fatigu e” (59935100) to the National Traction Power Laboratory, Southwest Jiaotong University. It is also supported by the Foundation for University Key Teacher by the Ministry of Education of China.
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轮辐的柔性变形结构的效果和在滚动接触的轮/ 轨道的潜变力的追踪
金学松吴平博文泽峰
中国成都 600031 西南交通大学国家的牵引动力实验室
摘录
在这一篇论文中，对滚动接触机械装置上的滚动接触体结构柔性变形的效果简短地分析。轮副和轨道对轮的潜变力的结构变形的效果和轨条详细地被分析研究。轮副的一般结构柔性变形和轨道首先分别用有限元的机械要素方法和关系一起分析,从而获得表达滚动方向和轮副的横方向的结构柔性变形和对应的负载。按照它们之间的关系,我们计算轮和轨条的在一点相接接触的影响力系数。影响力系数代表发生在轮/轨道接触的一个小的矩形面积上的单位面积的牵引力引起的结构柔性变形。他们习惯校订一些与Kalker的无赫兹的形状滚动接触的三维空间的有柔性体的理论 Bossinesq 和 Cerruti 的公式一起获得的影响力系数。在潜变力的分析中, 利用了修正的 Kalker 的理论。从轮副和轨道的结构柔性变形中获得的数字结果表明潜变力发挥的很大影响力。
2002 Elsevier 科学出版社版权所有。
关键字: 轮/轨条; 滚动接触;潜变力;柔性变形结构
1.介绍
由于火车轮副和轨道之间的很大相对运动作用力引起轮副和轨道的结构较大的柔性变形。大的结构变形极大影轮和轨条响滚动接触的性能,如潜变力，波形 [1 – 3] ，黏着，滚动接触疲劳, 噪音 [4,5] 和脱轨[6]等等. 到现在为止在轮/ 轨道的潜变力的分析中广泛应用的滚动接触理论是以柔性一半的空间假定为基础的 [7 –12]. 换句话说，轮/ 轨道的一个接触的柔性变形和牵引之间的关系可以用Bossinesq 和 Cerruti 的理论公式表达。实际, 当轮副在轨道上持续运动,接触的柔性变形是比那些以滚动接触的现在理论公式计算的更大。因为轮副/ 轨道的挠性是比柔性一半的空间更加大。由对应的负荷所引起的轮副/ 轨道柔性变形结构在图中被显示。如 1 和 2. 在图中轮副弯曲变形被显示出来。在图 1a 中被显示的轮副弯曲变形主要由车辆和轮副/轨条的垂直动载荷所引起。在图 1 b 中描述的轮副扭转的变形是由于轮和轨道之间的纵潜变力的作用生产的。在图 1 c 中显示的轮副斜角弯曲变形和在图 2 中显示的轨道翻折变形主要地由交通工具和轮副/轨道的横动态负荷所引起。在轮副 (图 1 d) 的轴周围的和旋转装置相同方向的扭转变形,火车可以使用的,主要在电动机的轮/ 轨条和驱动扭矩的接触补缀上的牵引所引起。到目前为止很少的出版物讨论滚动接触的轮副和轨道之间的爬动和潜变力的效果。
事实上，上面提到轮副/ 轨道的柔性变形结构是在轮/轨道的常态和切线的接触刚性以下运动。轮/ 轨道的正常的接触点的刚性通常低于轨道的下沉位置。
低于正常接触点的刚性很少的影响接触面积上的正常压力。那低于切线的接触刚性很大影响接触面积的黏结/ 滑移面积状态和牵引力。如果滚动接触的柔性变形结构的影响被对于轮/轨道的分析考虑进去，一对接触面积的全体微粒滑移与用现在滚动接触理论计算的结果不同。所有的连络颗粒和摩擦功的总的滑移比那在分析轮/轨道浅动力的时候，被忽略的柔性变形结构更小。同样一个接触面积的根/ 转差面积的比率比没有考虑的柔性变形结构的效果更大。在这一篇论文中，在滚动接触性能上的滚动接触的车体柔性变形机构的装置被简短地分析，而且和Kalker''''s 无赫兹的形状滚动接触的三度空间的有柔性车体的理论模型用来分析在轮副和轨道之间的潜变力。在数值分析中挑选的轮副和轨条分别地,是货车轮副的锥形轮廓，中国 "兆位元组" 和钢轨条的质量是60 公斤/m 。有限元分析方法用来决定他们的柔性变形结构。依照柔性变形结构的关系和对应的由于 FEM 获得负荷, 表示轮副的柔性变位的影响系数是由轮/ 轨条的接触单位面积密度有所反应的牵引生产的轨条所决定。这些影响系数用来代替一些与 Kalker''''s 的理论 Bossinesq 和 Cerruti 的公式一起计算的影响系数。在图 1a 中被显示的轮副弯曲变形的效果和在轮副轨道的柔性变形结构之中的横断的影响力在研究中被疏忽。获得的数字结果表明在轮副/轨道柔性变形结构的潜变力效果考虑和疏忽的条件之间的显着差别。
2. 减少连络刚性机构增加接触面积的根粘滞/滑动比
为了要使轮副/ 轨道关于滚动接触的轮/ 轨的的柔性变形结构的效果较好的理解, 我们必需简短地解释减少的接触刚性的机构增加在没有饱和的潜变力的状态下面的接触面积的粘滞/ 滑移面积的比。通常在一个接触面积的一对接触颗粒之间的总的滑移含有刚性的滑移,局部一个接触面积和柔性变形结构的柔性变形。图 3 a一描述一对滚动接触车体①和没有柔性变形②接触颗粒， A1 和 A2 的状态。在图 3 a中的线A1A 1 和 A2A 2, 为了要作描述的让大家接受而被作记号。在车体的形变发生之后,线的位和形变,A1A 1 和 A2A2,在图3 b 中被显示。位移差别 , w1, 在图 3 b 的二个划线之间由车体的刚性运动①和②所引起(滚动或变化). 局部点 A1 和 A2 的柔性变形,被 u11 和 u21 指示,与基于有柔性- 半份空间的假设滚动接触的一些现代的理论一起决定,他们有差别在于点 A1 和点A2之间的有柔性位移 u1= u11- u21。如果车体的结构柔性变形的效果和被忽视的A1 和 A2点之间的总转差 , 能用公式: S1 = w1 ?u1 = w1 ?(u11 ?u21)
表示。柔性变形结构车体 1 和 2 主要地由牵引力所引起,p 和 p 代表接触插线和车体的其他边界条件1和 2,他们做线,A1A 1 和 A2A 2 产生与接触面积的局部的坐标 (ox1x3,图 3 a) 无关的刚性运动。u10 和 u20 用来表达点 A1 和点A2的位移,各自归于结构柔性变形。在任何的荷载阶段他们为规定的边界条件和车体 1 和 2 的几何学可能被当做有不防碍局部的坐标常数。在点 A1 和点 A2 之间的位移差别取决于 u10 和 u20, 应该是 u0=
u10-u20。如此在考虑车体 1 和 2的柔性变形结构的条件之下,在点之间的总滑移 , A1 和A2,同样地用公式:S*1 = w1 - u1 - u0表示。明显的 S1 和 S?1 是不同的。在一对接触颗粒之间的牵引 ( 或潜变力)非常仰赖 S1( 或 S?1) 。当 |S1|>0(或 |S?1|>0)那对接触颗粒是在滑移中和牵引力进入饱和。在进入饱和的情形中, 依照库伦摩擦定律的如果一样的磨擦力系数而且正常的压力被假定的二个条件，牵引是相同的。如此对 u1 的牵引影响在二个条件之下也是相同的。如果 |S1|=|S?1|>0,|w1| 在 (2) 必须是比在(1)更大。即没有 u0 的影响的那对接触颗粒比有 u0 的影响的滑移更快。相应地没有 u0 的影响整个的接触面积进入滑移情况快于有 u0 的影响。因此，在接触面积上的粘滞/ 滑移面积的比率和在上面被讨论的二个类型的总牵引是不同的,他们只是被图 4a 和 b一起被简单描述。图 4a表明粘滞/ 滑移面积的情况。图 4a 的号讯 1 表明不考虑 u0 和 2的效果而指示外壳即用 u0 的效
果指示。图 4 b表示在接触面积上总的接触牵引力F1和车体的滑动关系的一种规律。在图4 b 中的号讯 1 和 2 和图 4 中的意义相同。从图 4 b 中已知 , 在一点相接牵引力 F1 在w1=w 时到达它的最大值 F1max 不考虑 u0 和 F1 接触的效果在 w1=w 它的最大 F1max 仅由于 u0 的效果来看w1< w 1. u0 主要仰赖于车体的柔性变形结构和在接触面积上的牵引力。大的柔性变形结构引起滚动接触的在二个车体之间的大 u0 和小的接触刚性。那是为什么增加一个接触面积的根/ 滑移面积的比率和减少没有全滑移的在接触面积的条件下面的全体的牵引力而减少的接触刚性。
3. 轮副/轨条的结构形变的计算
为了要计算在图 1 b – d, 和图 2 中被描述的柔性变形结构，轮副的离散化而且轨条被虚构。他们的 FEM 网目的方案
在图 5,7 和 9中被显示。假定轮副和轨条有相同的物理性质。剪[切]模量:G=82,000个牛顿/mm2,泊松比: μ=0.28. 图 5 用来决定轮副的扭转形变。因为,它是关于轮副 (图 1 b) 的中心对称,一个一半的轮副被选择来分析。轮副的切断横断面被安装,如图 5 所示一。负荷被应用到圆周方向轮副的胎面,在轮的不同的母圆上。荷载的分布分别位于从轮的内部边测量31.6,40.8 和 60.0毫米, 图 6 表示纵方向扭转的形变相对于负荷位置。他们都是线性载荷，载荷的不同点都非常接近。在图 5 中被显示Y轴方向形变的的负荷被忽略。
i=1,2 分别代表左边和右边的边轮/轨条。叁数 (3) 在现在的论文命名中被详细地义。如果它被倾斜，当轮副向轨道和ψ>0 的左边变档的时候 ,在顺时针方向,在轮副的轴线和左边的轨道的横向方向之间，我们定义那 y>0。叁数仰赖y 和ψ，轮和轨条的轮廓。但是如果轮和轨条的轮廓被指定他们主要地仰赖 y[16]. 详细的讨论用数字的方法被屈服[16,17] 和轮/轨条的接触几何学的结果。
当一个轮副移动到一个正切追踪刚性蠕动轮副和轨条的时候当做 [17]:
i=1,2时它有如同写在底下在(3)的 i 一样的意义。在 (4)的不明确的叁数能在命名法中看到。很明显蠕动不仅与接触几何学的叁数有关, 而且也与轮副运动的状态有关。因为接触几何学的叁数变化主要依靠一些他们的导出于计时轮/ 轨条的规定轮廓y的变化有关被记做：
把(5)放进(4)之内我们获得:
在轮/轨条的接触几何学和滑移的计算，大范围的偏角和轮副的横向位移被选用以便轮辐的滑移和接触角含尽可能完全地在磁场中被产生的情况被获得。因此我们选择
毫米
和
与中央的用不同的方法和ri, φ和 ?i 和
y l0=746.5mm ， r0=420mm比较的数字结果一起计算。使用选择的y ，ψ，˙ y/ v 和 r0 ˙ψ/ v 的范围在我们获得上面ξ i 1个范围从 ?0.0034 到 0.0034,ξ i 2个范围
从 ?0.03 到 0.03, ξ i 3 排列从 ?0.00013 到 0.00013(毫米?1), 和接触角δ i 是从到 2.88 到 55.83度。由于论文的长度限制滑动和接触几何学的详细数字的结果不被在这篇论文中显示。
4．结论
(1). 在滚动接触性能上的滚动接触车体的柔性变形结构的效果机构被简短地分析。一般了解连络车体的接触刚性减少则接触面积在不全滑移情形中的粘滞/ 滑移面积增加。
(2). Kalker's 的和无赫兹的形状滚动接触的三度空间的弹性体的理论模型被用来分析在轮副和轨道之间的潜动力。在分析中，有限元法被用决定作用于每个矩形元件单位牵引生产的轮副/轨道有柔性位移表达的影响系数,用来代替一些与 Kalker's 的理论Bossinesq 和 Cerruti 的公式一起计算的影响系数。被获得的数字结果表明在轮副/ 轨条结构柔性变形的效果被考虑和忽略的两种情况之下轮副/ 轨条类型的潜动力的差别。
(3). 轮副和轨道的柔性变形结构低于运行轮副和轨道的接触刚性, 而且在没有饱和
的潜动力的条件之下显着地减少在轮副和轨道之间的潜动力。因此，这种情况有利于减少磨损和轮与轨条的滚动接触疲劳。
(4).在研究中，在图 1 中显示的轮副弯曲形变的因素被忽略,而横断的影响系数
不被修正。因此，获得数字结果的精确度很低。除此之外, 当
轮副中心的横向位移, y>10 mm,凸圆作用发生。在如此的情形中，接触角非常大，而且横的方向正常负载的元件也非常大。大的横力引起轨道和轮副产生大的结构形变,影响轮/ 轨条的接触几何学的叁数和刚性的滑动。因此,刚性滑动,潜动力, 接触几何学的叁数，柔性变形结构和轮副的运动彼此有很大的影响。他们必需综合地分析考虑。他们的数字结果能与一个其它可能的迭代法一起获得
。或许共形的接触或轮和轨条之间的点接触在凸圆的作用期间发生。滚动接触的轮副和轨条的现象是非常复杂的, 而且可能与可能是包括结构形变和包括轮副和轨道的所有边界条件在不久的将来内的效果 FEM 模型的滚动接触的一个新的理论被分析。
这一个工作被研究计划的中国自然的科学基础委员会支持了: 轮和轨条和滚动接触疲劳的接触表面的波形。(59935100)国家牵引动力实验室,西南交通大学。
它也被中国的教育部键老师大学也提供基金支持。
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机械设计理论 机械设计是一门通过设计新产品或者改进老产品来满足人类需求的应用技术科学。它涉及工程技术的各个领域，主要研究产品的尺寸、形状和详细结构的基本构思，还要研究产品在制造、销售和使用等方面的问题。 进行各种机械设计工作的人员通常被称为设计人员或者机械设计工程师。机械设计是一项创造性的工作。设计工程师不仅在工作上要有创造性，还必须在机械制图、运动学、工程材料、材料力学和机械制造工艺学等方面具有深厚的基础知识。如前所诉，机械设计的目的是生产能够满足人类需求的产品。发明、发现和科技知识本身并不一定能给人类带来好处，只有当它们被应用在产品上才能产生效益。因而，应该认识到在一个特定的产品进行设计之前，必须先确定人们是否需要这种产品。 应当把机械设计看成是机械设计人员运用创造性的才能进行产品设计、系统分析和制定产品的制造工艺学的一个良机。掌握工程基础知识要比熟记一些数据和公式更为重要。仅仅使用数据和公式是不足以在一个好的设计中做出所需的全部决定的。另一方面，应该认真精确的进行所有运算。例如，即使将一个小数点的位置放错，也会使正确的设计变成错误的。 一个好的设计人员应该勇于提出新的想法，而且愿意承担一定的风险，当新的方法不适用时，就使用原来的方法。因此，设计人员必须要有耐心，因为所花费的时间和努力并不能保证带来成功。一个全新的设计，要求屏弃许多陈旧的，为人们所熟知的方法。由于许多人墨守成规，这样做并不是一件容易的事。一位机械设计师应该不断地探索改进现有的产品的方法，在此过程中应该认真选择原有的、经过验证的设计原理，将其与未经过验证的新观念结合起来。 新设计本身会有许多缺陷和未能预料的问题发生，只有当这些缺陷和问题被解决之后，才能体现出新产品的优越性。因此，一个性能优越的产品诞生的同时，也伴随着较高的风险。应该强调的是，如果设计本身不要求采用全新的方法，就没有必要仅仅为了变革的目的而采用新方法。 在设计的初始阶段，应该允许设计人员充分发挥创造性，不受各种约束。即使产生了许多不切实际的想法，也会在设计的早期，即绘制图纸之前被改正掉。只有这样，才不致于堵塞创新的思路。通常，要提出几套设计方案，然后加以比较。很有可能在最后选定的方案中，采用了某些未被接受的方案中的一些想法。
会计内部控制中英文对照外文翻译文献
会计内部控制中英文对照外文翻译文献(文档含英文原文和中文翻译)
内部控制透视：理论与概念 摘要：内部控制是会计程序或控制系统，旨在促进效率或保证一个执行政策或保护资产或避免欺诈和错误。内部是一个组织管理的重要组成部分。它包括计划、方法和程序使用，以满足任务，目标和目的，并在这样做，支持基于业绩的管理。内部控制是管理阶层的平等与控制可以帮助管理者实现资源的预期的有效管理的结果通过。内部控制应减少或违规错误的风险关联未被发现的，但设计和建立有效的内部控制不是一个简单的任务，不可能是一个实现通过快速修复短套。在此讨论了内部文件的概念的不同方面的内部控制和管制。 关键词：内部控制，管理控制，控制环境，控制活动，监督 1、介绍 环境需要新的业务控制变量不为任何潜在的股东和管理人士的响应因子为1，另外应执行/她组织了一个很大的控制权。控制是管理活动的东西或以上施加控制。思想的产生和近十年的发展需要有系统的商业资源和控制这种财富一个新的关注。主题之一热一回合管制的商业资源是分析每个控制成本效益。 作为内部控制和欺诈的第一道防线，维护资产以及预防和侦查错误。内部控制，我们可以说是一种控制整个系统的财务和其他方面的管理制定了为企业的顺利运行;它包括内部的脸颊，内部审计和其他形式的控制。 COSO的内部控制描述如下。内部控制是一个客观的方法用来帮助确保实现。在会计和组织理论，内部控制是指或目标目标的过程实施由组织的结构，工作和权力流动，人员和具体的管理信息系统，旨在帮助组织实现。这是一种手段，其中一个组织的资源被定向，监控和测量。它发挥着无形的（重要的作用，预防和侦查欺诈和保护组织的资源，包括生理（如，机械和财产）和乙二醇，声誉或知识产权，如商标）。在组织水平，内部控制目标与可靠性的目标或战略的财务报告，及时反馈业务上的成就，并遵守法律，法规。在具体的交易水平，内部控制是指第三方采取行动以实现一个具体目标（例如，如何确保本组织的款项，在申请服务提供有效的。）内部控制程序reduce程变异，导
机械类毕业设计外文翻译
本科毕业论文(设计) 外文翻译 学院：机电工程学院 专业：机械工程及自动化 姓名：高峰 指导教师：李延胜 2011年05 月10日 教育部办公厅 Failure Analysis，Dimensional Determination And
Analysis，Applications Of Cams INTRODUCTION It is absolutely essential that a design engineer know how and why parts fail so that reliable machines that require minimum maintenance can be designed．Sometimes a failure can be serious，such as when a tire blows out on an automobile traveling at high speed．On the other hand，a failure may be no more than a nuisance．An example is the loosening of the radiator hose in an automobile cooling system．The consequence of this latter failure is usually the loss of some radiator coolant，a condition that is readily detected and corrected．The type of load a part absorbs is just as significant as the magnitude．Generally speaking，dynamic loads with direction reversals cause greater difficulty than static loads，and therefore，fatigue strength must be considered．Another concern is whether the material is ductile or brittle．For example，brittle materials are considered to be unacceptable where fatigue is involved． Many people mistakingly interpret the word failure to mean the actual breakage of a part．However，a design engineer must consider a broader understanding of what appreciable deformation occurs．A ductile material，however will deform a large amount prior to rupture．Excessive deformation，without fracture，may cause a machine to fail because the deformed part interferes with a moving second part．Therefore，a part fails(even if it has not physically broken)whenever it no longer fulfills its required function．Sometimes failure may be due to abnormal friction or vibration between two mating parts．Failure also may be due to a phenomenon called creep，which is the plastic flow of a material under load at elevated temperatures．In addition，the actual shape of a part may be responsible for failure．For example，stress concentrations due to sudden changes in contour must be taken into account．Evaluation of stress considerations is especially important when there are dynamic loads with direction reversals and the material is not very ductile． In general，the design engineer must consider all possible modes of failure，which include the following． ——Stress ——Deformation ——Wear ——Corrosion ——Vibration ——Environmental damage ——Loosening of fastening devices
外文翻译(土木专业)
模拟在火灾情况下加载对构造柱行为的影响 作者： 阿尼尔阿加瓦尔，普渡大学西拉法叶，在47906，anilag@https://www.360docs.net/doc/bd12528003.html, 阿米特阁下瓦玛，普渡大学西拉法叶，在47906，ahvarma@https://www.360docs.net/doc/bd12528003.html, 本文介绍了在光纤梁柱的有限元建模发展的基础上，模拟梁柱和其他构件在火灾高温情况下受荷的结构行为。几个这样的单元可以结合起来：（一）模型结构构件和框架（二）在火灾情况下分析它们，有限元程序是在一个土著有限元分析程序，使用改进的牛顿拉夫逊（星期日）迭代求解算法进行非线性分析。该文件还为简单的基准的方案问题以及钢柱在最近进行的火灾测试提供了有限元的有限验证。审定、采用有限元参数进行分析，以探讨在火灾情况下钢柱负荷强度的结构参数和约束作用 1.0简介 目前的建筑法规（例如，国际生物伦理委员会2005年）强调规范建筑钢结构防火抗震设计。用标准的ASTM E119进行测试以确定各组成部分的防火等级。由于工具简单，火灾的标准测试结果的适用性是有限的，通过这些测试推断出结果，提供一个在现实的火灾情况下洞察整个结构和各个组成部分的基本行为的途径。目前，急需一个简单的分析模型和方法，以用来从一定精度上模拟在标准火灾作用下，个别结构构件的行为以及它们之间相互作用。这些模型必须基于基本原则，适用于参数研究，同时能容易地探索设计方案。本文论述了一个结论的发展和验证，即一个简单的2个节点的有限梁柱元素，可以用来模拟和分析在火灾荷载下整个结构。对一些参数进行研究，探讨边界条件和其它的约束作用，以及钢柱受到的轴向和热负荷作用下的破坏。 2.0纤维配方基于2 -节点有限元 一个2节点有限元已制订的c0曲率在节点的连续性和一个三次埃尔米特多项式形函数。荷载被假定为只作用在一个元素的节点上，这个元素有两个结合点，在每个端部各一个，拟议的梁柱元素设计是考虑到结构的几何非线性和材料非线性。完整的工具，包括元素和计算程序，有能力对只承受弯曲变形或轴向变形的任何截面做出分析。以下分节讨论了该模型的突出问题。 2.1热负荷 该元素能将热膨胀的影响和由于温度变化所引起的材料性能的改变结合起来。全截面纤维可以被分配在不同的温度和在温度非均匀情况下分布，压力和弯曲的情况也是全截面分布的，使截面图保持水平，外部作用平衡外部作用。香港开发的分析程序（2007）可以用来计算给定播映时间的温度曲线整个路段的温度。计算工具得到了进一步的修改，以允许用户通过宽翼缘部分（图1）给定的7个点，输入时间温度曲线。该方案在特定值中插值以计算每个截面纤维的温度。 2.2材料性能 该方案有能力建模钢、钢筋混凝土，以及诸如钢管混凝土管（桂林工学院）的复合元素。变温单轴应力应变曲线必须是一节中使用的特定的材料。目前的工作，重点是在钢柱。博爱医院所提出的温度依赖性钢的应力应变曲线（2001）已用
机械类外文翻译
机械类外文翻译 塑料注塑模具浇口优化 摘要:用单注塑模具浇口位置的优化方法，本文论述。该闸门优化设计的目的是最大限度地减少注塑件翘曲变形，翘曲，是因为对大多数注塑成型质量问题的关键，而这是受了很大的部分浇口位置。特征翘曲定义为最大位移的功能表面到表面的特征描述零件翘曲预测长度比。结合的优化与数值模拟技术，以找出最佳浇口位置，其中模拟armealing算法用于搜索最优。最后，通过实例讨论的文件，它可以得出结论，该方法是有效的。 注塑模具、浇口位臵、优化、特征翘曲变形关键词: 简介 塑料注射成型是一种广泛使用的，但非常复杂的生产的塑料产品，尤其是具有高生产的要求，严密性，以及大量的各种复杂形状的有效方法。质量ofinjection 成型零件是塑料材料，零件几何形状，模具结构和工艺条件的函数。注塑模具的一个最重要的部分主要是以下三个组件集:蛀牙，盖茨和亚军，和冷却系统。拉米夫定、Seow(2000)、金和拉米夫定(2002) 通过改变部分的尼斯达到平衡的腔壁厚度。在平衡型腔充填过程提供了一种均匀分布压力和透射电镜,可以极大地减少高温的翘曲变形的部分～但仅仅是腔平衡的一个重要影响因素的一部分。cially Espe,部分有其功能上的要求,其厚度通常不应该变化。 pointview注塑模具设计的重点是一门的大小和位臵,以及流道系统的大小和布局。大门的大小和转轮布局通常被认定为常量。相对而言,浇口位臵与水口大小布局也更加灵活,可以根据不同的零件的质量。 李和吉姆(姚开屏,1996a)称利用优化流道和尺寸来平衡多流道系统为multiple 注射系统。转轮平衡被形容为入口压力的差异为一多型腔模具用相同的蛀牙,也存
管理 审计 外文翻译 外文文献 英文文献 内部控制爆X炸
外文出处：Maijoor S. The Internal Control Explosion[J]. International Journal of Auditing, 2000, 4(1):101–109. 内部控制爆炸① 摘要：Power的1997版书以审计社会为主题的探讨使得审计活动在联合王国（英国）和北美得到扩散。由审计爆炸一同带动的是内部控制制度的兴起。审计已经从审计结果转向审计制度和内部控制，它已内部控制爆炸然成为公众对公司治理和审计监管政策的辩论主题。Power表示对什么是有效的内部控制各方说法不一。本人对内部控制研究方面有一个合理的解释。内部控制对非常不同概念的各个领域的会计进行探究，并研究如何控制不同水平的组织。因此，内部控制研究的各类之间的交叉影响是有限的，而且，许多内部会计控制是研究是再更宽广的公司治理问题的背景下进行的。所以，许多有关内部控制制度对公司治理的价值观点扔需要进行研究。 关键词：机构理论；公司治理；外部审计；内部审计；内部控制制度；管理控制 1 概述 Power的1997版书以审计社会为主题的探讨使得审计活动在联合王国（英国）和北美得到扩散。由审计爆炸一同带动的是内部控制制度的兴起。审计已经从审计结果转向审计制度和内部控制，它已然成为公众对公司治理和审计监管政策的辩论主题。例如，在最近的对于欧洲联盟内外部审计服务的内部市场形成的辩论中，监管建议建立关于内部控制和内部审计制度。虽然对有关内部控制的价值期望高，但Power表示对什么是有效的内部控制各方说法不一。本人对内部控制研究方面有一个合理的解释。内部控制是对非常不同概念的各个领域的会计进行探究，并研究如何控制不同水平的组织。因此，内部控制研究的各类之间的交叉影响是有限的，而且，许多内部会计控制是研究是再更宽广的公司治理问题的背景下进行的。所以，许多有关内部控制制度对公司治理的价值观点扔需要进行研究。 在审计和公司治理的公共政策辩论中，内部控制的概念越来越得到重视。公共越来①Maastricht Accounting and Auditing Research and Education Center (MARC), Faculty of Economics and Business Administration, Universiteit Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands s.maijoor@marc.unimaas.nl Fax: 31-43-3884876 Tel: 31-43-3883783
机械类毕业设计外文文献翻译
沈阳工业大学工程学院 毕业设计（论文）外文翻译 毕业设计（论文）题目：工具盒盖注塑模具设计 外文题目：Friction , Lubrication of Bearing 译文题目：轴承的摩擦与润滑 系（部）：机械系 专业班级：机械设计制造及其自动化0801 学生姓名：王宝帅 指导教师：魏晓波 2010年10 月15 日
外文文献原文： Friction , Lubrication of Bearing In many of the problem thus far , the student has been asked to disregard or neglect friction . Actually , friction is present to some degree whenever two parts are in contact and move on each other. The term friction refers to the resistance of two or more parts to movement. Friction is harmful or valuable depending upon where it occurs. friction is necessary for fastening devices such as screws and rivets which depend upon friction to hold the fastener and the parts together. Belt drivers, brakes, and tires are additional applications where friction is necessary. The friction of moving parts in a machine is harmful because it reduces the mechanical advantage of the device. The heat produced by friction is lost energy because no work takes place. Also , greater power is required to overcome the increased friction. Heat is destructive in that it causes expansion. Expansion may cause a bearing or sliding surface to fit tighter. If a great enough pressure builds up because made from low temperature materials may melt. There are three types of friction which must be overcome in moving parts: (1)starting, (2)sliding, and(3)rolling. Starting friction is the friction between two solids that tend to resist movement. When two parts are at a state of rest, the surface irregularities of both parts tend to interlock and form a wedging action. To produce motion in these parts, the wedge-shaped peaks and valleys of the stationary surfaces must be made to slide out and over each other. The rougher the two surfaces, the greater is starting friction resulting from their movement . Since there is usually no fixed pattern between the peaks and valleys of two mating parts, the irregularities do not interlock once the parts are in motion but slide over each other. The friction of the two surfaces is known as sliding friction. As shown in figure ,starting friction is always greater than sliding friction . Rolling friction occurs when roller devces are subjected to tremendous stress which cause the parts to change shape or deform. Under these conditions, the material in front of a roller tends to pile up and forces the object to roll slightly uphill. This changing of shape , known as deformation, causes a movement of molecules. As a result ,heat is produced from the added energy required to keep the parts turning and overcome friction. The friction caused by the wedging action of surface irregularities can be overcome