变椭圆轨迹振动筛的动力学和筛选特性外文翻译（可编辑）

1、变椭圆轨迹振动筛的动力学和筛选特性外文翻译 优秀资料 景德镇陶瓷学院毕业设计论文有关外文翻译 院 系:机械电子工程学院 专 业:机械设计制造及其自动化 姓 名:黄 荣 军 学 号: 200810310436 指导教师:吕 冬 青 完成时间:2012-04-15 说明1、将与课题有关的专业外文翻译成中文是毕业设计(论文)中的一个不可缺少的环节。此环节是培养学生阅读专业外文和检验学生专业外文阅读能力的一个重要环节。通过此环节进一步提高学生阅读专业外文的能力以及使用外文资料为毕业设计服务,并为今后科研工作打下扎实的基础。2、要求学生查阅与课题相关的外文文献3篇以上作为课题参考文献,并将其中1篇(不少

2、于3000字)的外文翻译成中文。中文的排版按后面格式进行填写。外文内容是否与课题有关由指导教师把关,外文原文附在后面。3、指导教师应将此外文翻译格式文件电子版拷给所指导的学生,统一按照此排版格式进行填写,完成后打印出来。4、请将封面、译文与外文原文装订成册。5、此环节在开题后毕业设计完成前完成。6、指导教师应从查阅的外文文献与课题紧密相关性、翻译的准确性、是否通顺以及格式是否规范等方面去进行评价。 指导教师评语:签名:年 月日变椭圆轨迹振动筛的动力学和筛选特性何小梅,刘楚生机械和电气工程学院,中国矿业大学科技,江苏省徐州市221116,中国 摘要:根据恒床厚度的筛选过程振动筛理想运动特征被提出

3、, 提出了一个新的振动筛变椭圆跟踪。 准确的力学模型建立,根据所需的结构构造运动特征。 应用多种学位自由度振动理论、特点,分析振动筛的。 振动筛运动参数获得,它的运动轨迹有线性的,圆的,椭圆的。振动筛的运动动态方程可通过计算机模拟得以有效的解决。屏幕表面五个特殊的点的技术参数,包括振幅,运动速度和引发指数,是通过理论计算获得。 结果显示,新设计的振动筛的轨迹遵循理想的筛选运动。筛分效率及处理能力可能因此而有效改进。 关键字:变椭圆轨迹;筛选过程与常量床厚度;动态模型;运动特性; 筛选特征 1介绍 筛分操作是一个重要的煤矿处理组成部分。振动筛是最广泛使用的筛选工具之一。 振动筛,如直线振动筛、圆

4、振动筛或椭圆振动筛,有一个简单的平移运动。在筛面上处处运动保持相同的运输速度和引发指数的,从而导致低效率的筛选。充实的抛掷指数提高加工能力打破了电机或降低了工作强度。 在本文中,我们报告的设计,一个新的振动筛变运动的痕迹,原则的基础上筛选过程固定床厚度不同的部分。振动筛穿越不同的椭圆轨迹和由此产生的议案,同意与理想的运动。因此,屏幕处理能力和效率均可以提高。 2振动表面的理想运动和变椭圆轨迹振动筛的建议 2.1振动筛常见的筛选特性 振动筛通常工作在固定振动筛上的物料表面强度。移动投掷,滚动或滑动运动”。 为常见的安检,物料粒度广泛分布在进料端的能量传递。物质粒子的振动筛严重消退。因此,大量颗粒

5、层只有很短的距离饲料结束。材料穿透屏幕在第一个1/ 4到1 /2的屏幕,它影响筛选和降低加工能力的。减少细粒物质导致比粒子的大小接近或大于网格。因此,筛分效率下降惊人。物料粒度同时统一的,从振动源给予物料的能量损失很小。因而物料粒子的振幅和速度增加。这导致了物料的垂直深度在送电端厚,而在放电结束端薄,进而影响了筛分效率和处理能力。常见的筛分特性如图1. 2.2屏幕表面的理想运动和实施方案根据筛选过程恒床等厚的原则,理想的运动的屏幕表面的描述如下。 3 变椭圆轨迹振动筛的动力学模型分析我们激振力偏离中心 重力,要更改新的运动模式 振动筛。 刚度矩阵的振动 隔离春天是根据这些不是零 情况和振动系统

6、有多重 自由度。 小横摇 被忽视的简化研究。 议案 被认为是刚性梁的非线性振动 纵向对称平面。 在每个点 振动是一个组合翻译 的重心和屏幕投球 重心。 以前的研究被忽视 水平弹性势力的影响 垂直方向振动的秋千 屏幕 311准确的动态模型组成 包括耦合的三个微分方程 自由度在垂直、水平和 摆动方向建议。 振动筛的数学模型 图中所示.2。 重力澳中心,采取 直角坐标系的原点在静态 均衡,按照刚性运动 平面 12微分方程组 广义坐标使用重心 坐标x、y和秋千赤纬角, ,可以写成: 其中m是振动筛的质量;j# 转动惯量美元相对于中心 重力,澳;x和y的x和y位移 方向;x和y在x和y的速度 方向;加速

7、x和y在x和 你们方向;is摆动角位移; the安装角度;外汇、f横跨萨杨德河fthe 阻尼系数在x、y anddirections; k和k ythe刚度系数的支持 沿x和y directions;a0汀春天 激振力的振幅,提供的 2 0 mr, 偏心其中r为半径,m的质量 偏心块andthe刺激角频率; 1 我和l2每个之间的距离支持 春季和重心,我的距离 偏心块的旋转中心之间 重心;而the夹角 我和x路之间。 阻尼力 相当小,可以忽略。 然后,式(1)可以简化式(2)。 4变椭圆轨迹振动筛的运动和筛选的效果分析4.1个分析的运动参数多自由度振动理论用来寻找一个稳定解的强迫振动 13,如

8、下:替代参数在式(3)到(2)式。允许一个稳定的解决方案被发现。 假设一个点的屏幕坐标为ddx,dy.运动方程如下: 当,d点的轨迹是一条直线。当es,chs时,d点的轨迹是圆。 一般来说,(6)式表示方程的椭圆面直角坐标系。xoy坐标系以角速度逆时针旋转从而给定一个新的坐标系。一个标准的椭圆公式在消除xdyd后可得公式(7)。从这我们知道有些屏幕上的点 移动或圆的行中,而其他移动 椭圆。 只要旋转的相对位置 偏心块的中心和重心 正确调整,变椭圆运动 屏幕将获得的。 这提供了一个合理的 扔指数和材料传递速度和 提高筛分效率。4.2 运动轨迹和筛分效率分析稳定振动系统解决方案,就振动筛而言的,可

9、以给出在振动筛上任一点的运动方程为公式(8)表示重心的痕迹近似圆形,水平和垂直方向的振幅在3.5mm 和5mm之间。图 3表示如重心的移动存在三个自由度。图3水平和垂直方向的相位差和摆角的振幅一样。 5 结论1)新振动筛变椭圆 根据原则提出了运动轨迹 常数床厚度的筛选过程。 振动筛跟踪不同的不同点 椭圆路径。 运动规律也同意配合 筛面的理想运动特性。 因此,筛选能力和处理效率 会增加。2)振动的理论运动学分析 屏幕做是为了研究如何变不同 参数会影响屏幕的议案。 电影 抽搐振动筛参数的议案 线性跟踪,获得圆或椭圆。 3 总振动筛运动的痕迹 通过计算机模拟获得。 筛选 技术参数,包括振幅, 速度和

10、引发指数,五个的特定点 沿屏幕表面计算。 这些 参数是与筛分效率。 结果显示模式设计的议案 振动筛符合理想的筛选 议案,设计能够有效 提高筛分效率。 4 励磁机轴中心的地位,相对 振动筛的重心,是 筛选高效的极为重要的。 因此,我们 可以设计一个振动筛具有更高的处理 的能力而又不会增加功耗 调整轴中心的相对位置。 这.。 是一个点,需要进一步研究。 参考文献1 wen b c,liu f q.振动的理论与应用机器.北京:中国机械出版,19822 gu q b,zhang e g.复杂轨迹振动筛研究. 19981:42?463 hao f y.煤制备手册:技术设备.北京:中国煤炭行业出版社,19

11、934 yan f.筛分机械.北京:中国煤炭行业出版社.19955 liu c s,zhao y m.筛面上的非线性特性的研究. 矿物处理设备,19991:45?48 6 tao y j,luo z f,zhao y m.在重力强力分离器使用方面的煤脱硫的实验研究.中国矿业与技术大学. 2006,164:399?4037zhang e g.筛分,粉碎,脱水设备.北京:中国煤工业出版社,19918 khoury d l.煤清洁工艺.美国:诺易斯数据公司,19819 shang n x,na j f. 2tya1842圆振动筛.矿业与加工设备,19902:20?2410 ye h d.等厚圆筛分及

12、其应用. 烧结和码垛, 1999,53:30?3311 wen b c,liu s y,he q.振动机械理论和动力学设计方法.北京:中国机械出版社,200112 wang f,wang h.筛分机械. 北京:中国机械出版社,2001 13 ni z h.振动力学.西安:西安交通大学出版社,198914 zhu w b.复杂运动轨迹振动筛的工作原理和计算机仿真.矿业与加工设,200410:34?3615 peder m.莫根深系列?一种新型的筛分概念.矿物加工,1996,737:311?31516 wen b c.圆振动筛的自动同步理论.波士顿:美国机械工程协会,1987:495?500. d

13、ynamics and screening characteristics of a vibrating screen with variable elliptical trace he xiao-mei,liu chu-sheng school of mechanical and electrical engineering,china university of mining & technology,xuzhou,jiangsu 221116,china abstract: the ideal motion characteristics for the vibrating screen

14、 was presented ,according to the principle of screening process with constant bed thickness. a new vibrating screen with variable elliptical trace was proposed. an accurate mechanical model was constructed according to the required structural motion features.applying multi-degree-of-freedom vibratio

15、n theory,characteristics of the vibrating screen was analyzed.kinematics parameters of the vibrating screen which motion traces were linear,circular or elliptical were obtained.the stable solutions of the dynamic equations gave the motions of the vibrating screen by means of computer simulations.tec

16、hnological parameters,including amplitude,movement velocity and throwing index,of five specificpoints along the screen surface were gained by theoretical calculation .the results show that the traces of the new designed vibrating screen follow the ideal screening motion .the screening efficiency and

17、 processing capacity may thus be effectively improved. keywords:variable elliptical trace;screening process with constant bed thickness; dynamic model;motion characteristic;screening characteristics 1 introduction screening operations are an important part of coal processing. the vibrating screen is

18、 one of the most extensively used screening tools. vibrating screens, such as linear vibrating screen, circular vibrating screen or elliptical vibrating screen, have a simple translational motion. the motion follows the same path everywhere on the screen and so the screen has constant transport velo

19、city and throwing index, which leads to low screening efficiency. augmenting the throwing index to improve breaks the exciting motors processing capacity lowers the working. in this paper , we report on the design of a new vibrating screen with variable motion traces that is based on the principle o

20、f screening process with constant bed thickness3?4.different parts of the vibrating screen traverse different elliptical traces and the resulting motion agrees well with the ideal motion .thus the screen processing capacity and efficiency can both be improved. 2 ideal motion for a screen surface and

21、 the proposal of a vibrating screen with variable elliptical trace 2.1 screening characteristics of common vibrating screens vibrating screens commonly work at a fixed vibration intensity .material on the screen surface moves by throwing, rolling or sliding motions .for common screeners ,material gr

22、anularity is widely distributed at the feed end .the energy imparted to the material particles from the vibrating screen is severely dissipated .consequently ,a large number of particles become laminated only a short distance from the feed end .the material penetrates the screen within the first 1/4

23、 to 1/2 of the screen ,which affects screening and lowers processing capacity 5.the decrease of fine-grained material causes the ratio of particles close in size to ,or larger than ,the mesh to increase .thus ,the screening efficiency declines dramatically .the material granularity simultaneously be

24、comes uniform and the energy imparted from the vibrations to the material suffers little loss .hence ,the amplitude and velocity of the material particles increase .this causes the material bed depth at the feed end to be thick while at the discharge end it isthin .this kind of motion leads to an as

25、ymmetrical penetration along the screen surface,which influences the screening efficiency and processing capability 6mon screening characteristics are shown in fig.1. 2.2 ideal motion for screen surface and implementing scheme the ideal motion for screen surface is described below, according to the

26、principle of screening process with constant bed thickness .the feed end of the screen has a bigger throwing index and a higher material delivery velocity ,which makes bulk material quickly penetrate and causes rapid de-laminating. earlier lamination of material increases the probability of fine-gra

27、ined material passing through the mesh .the screen has an appropriate throwing index and a little higher material delivery velocity in its middle part .this is of benefit for stabilizing fine-grained materials and for penetrating uniformly along the screen length .a lower throwing index and material

28、 delivery velocity near the discharge end causes the material to stay longer on the screen and encourages more complete penetration of the mesh. two methods are currently used to improve screening efficiency 7?8.the first is to add material to the screen from multiple feed ports. this is troublesome

29、 in practical use especially in terms of controlling the distribution of differently granulated materials .hence it is rarely used in practical production. the second way is to adopt new screening equipment like, for example, a constant thickness screen. the motion of the new screen surface causes m

30、aterial to maintain the same, or an increased, thickness .it achieves a rather more ideal motion. the main problem with the constant thickness screen is that it covers a bigger area and that the structure is complicated and hard to maintain .a simple structure with good screening efficiency is still

31、 a necessity. we have designed a new vibration screen with a variable elliptical trace that is based upon an ideal screen motion for use in raw coal classification. the size of the vibrating screen is 3.6 m7.5 m,the feed granularity is 0 to 50 mm and the classification granularity is 6mm.ellipticall

32、y vibrating screens combine the basic advantages of both circular and linear vibrating screens 9?10.the long axis of the ellipse determines material delivery and the short axis influences material loosening, to be exact. 3 dynamics model analysis of vibrating screen with variable elliptical trace we

33、 made the exciting force deviate from the center of gravity,to change the motion pattern of the new vibrating screen.the stiffness matrix of the vibration isolation spring was not zero under these circumstances and the vibrating system had multiple degrees of freedom.minor transverse wagging was neg

34、lected to simplify the research.the motion was considered to be a linear vibration of a rigid beam in the longitudinally symmetrical plane.at each point the vibration is a combination of the translation of the center of gravity and the screen pitching about the center of gravity.previous studies neg

35、lected the influence of elastic forces in the horizontal and vertical direction on the swing of the vibrating screen 3,11.an accurate dynamic model consisting of three differential equations that include coupling of degrees of freedom in the vertical,horizontal and swing directions is proposed. the

36、mathematical model of the vibrating screen is shown in fig.2.the center of gravity, is taken as the origin of a rectangular coordinate system at staticequilibrium, in accordance with rigid motion on the plane 12.simultaneous differential equations in generalized coordinates using center of gravity c

37、oordinates,x,y,and the swing declination angle, ,may be written aswhere m is the mass of the vibrating screens the moment of inertia of m relative to the center of gravity,o;x and y the displacements in the x and y0directionas;x and y the velocities in the x and y directions and y the accelerations

38、in the x and y directions; is the swing angular displacement; the installation angle;fx,f yond father damping coefficients in the x,y and directions;x k and k the stiffness coefficients of the supporting spring along the x and y directions; a0 the amplitude of the exciting force, given by2 0 a mr, w

39、here r is the radius of eccentricity the mass of the eccentric block and the exciting angular frequency; l1 and l2 the distances between each supporting spring and the center of gravitys the distance between the rotating center of the eccentric block and the center of gravity; and,the included angle

40、 between the l and x directions. the damping force is rather small and can be neglected. then eq. 1 can be simplified to eq.2.4 motion and screening effect analysis of a vibrating screen with variable elliptical trace4.1 analysis of the motion parameters multiple degree-of-freedom vibration theory w

41、as used to find a stable solution for the forced vibration 13,as follows: when e 2 s 2 +c 2 h 2 +2 esch0, the trace of point d is a line. when e sand c h, the trace of point d is a circle. in general. 6 expresses the equation of an ellipse.the xoy coordinate was rotated degrees anticlockwise to give

42、 a new set of x oycoordinates. a standard elliptical equation was then obtained after eliminating d d x y in eq.7. from this we know that some points on the screen move in a line or a circle while others move in an ellipse .as long as the relative position of the rotating center of the eccentric blo

43、ck and the center of gravity are properly adjusted, variable elliptical motion of the screen will be obtained .this provides a reasonable throwing index and material delivery velocity and improves screening efficiency. 4.2 analysis of motion trace and screening efficiency the stable solution of a vi

44、brating system, in terms of the vibrating screen, can be given by the equations of motion for any point on the vibrating screen are eq.8shows that the center of gravity traces an approximate circle and that the amplitude in the horizontal and vertical directions is between 3.5 mm and 5 mm.fig.3 show

45、s how the center of gravity moves in three degrees of freedom.fig.3 gives theangular phase difference between the horizontal and vertical directions as well as the amplitude of the swing angle.5 conclusions 1a new vibrating screen with variable elliptical motion trace was proposed according to the p

46、rinciple of screening process with constant bed thickness.different points on the vibrating screen trace differentelliptical paths.the motion pattern agrees well with the ideal motion characteristic for a screening surface. thus,screening capacity and process efficiency can be increased. 2a theoreti

47、cal kinematic analysis of the vibrating screen was done to study how varying different parameters affects the motion of the screen.kinema- tics parameters of the vibrating screen that motion traces are linear,circular or elliptical are obtained. 3 motion traces of total vibrating screen were gained

48、through computer simulations.screening technological parameters,including amplitude, velocity and throwing index,of five specific points along the screen surface were calculated. theseparameters are related to screening efficiency. the results show that the motion pattern of the designed vibrating s

49、creen conforms to an ideal screening motion and that the design is able to effectively improve screening efficiency. 4the position of the exciter axle center,relative to the center of gravity of the vibrating screen,is extremely important for screening efficient.thus,we can design a vibrating screen with higher processing capacity without increasing power consumption by adjusting the relative position of the axle center.this is a point that requires further study. references 1wen b c,liu f q.theory and application of vibration machines.beijing:china machine p