机械毕业设计英文外文翻译243基于有限元法,旋耕机传动齿轮应力分析
基于有限元法，旋耕机传动齿轮应力分析
·穆罕默德托帕克库萨特西里克丹妮资耶尔马兹易卜拉欣阿辛琪阿克登尼基大学农学院，安塔利亚，土耳其农业机械部
2008年8月12日
摘要
旋耕机的耕作工具，获取自己的运动由拖拉机动力起飞（PTO）有被设计为混合土。降低土壤交通在很大程度上与此工具混合土。使用旋耕机是提高我国由于其许多优点。旋耕机结构具有一个齿轮箱，改变运动方向由拖拉机动力输出轴90度，旋转速度传动齿轮和转子轴放置在水平的土壤混合。
有刀片在进入转子轴件和混合土。特别是，在刀片和传动齿轮，变形发生由于高无振动，高功率，土壤的部分影响，使用条件设计制造误差和错误。特别是用于建筑和传动部件的应力分布，为理解好的确定失败的原因。在这项研究中，传动的旋耕机而设计制造的一种本地制造商被建模为三维参数化设计软件和结构应力在根据其工作使用有限元软件模拟了在传动齿轮的分布条件。后仿真结果评价，对齿轮应力分布表明，齿轮工作无故障根据齿轮的材料应力屈服。此外，计算的参考齿轮工作安全系数仿真结果。
关键词：旋耕机，应力分析，有限元法
1.引言
旋耕机耕作机，适用于农田、果园，在农业。旋耕机有削减巨大的能力，混合土和苗床准备直接制备。此外，旋耕机有更多的混合能力是比犁的七倍。
旋耕机是连接到拖拉机三点联动系统，它是由拖拉机动力输出轴驱动（PTO）。运动的方向改变90度，从拖拉机动力输出第二齿轮箱的水平轴。转子轴与第二齿轮箱的运动。
旋耕机的元素在其他作用力下由于高无振动，高功率，土壤的部分影响，设计制造错误和错误的使用条件，耕作。因此，不需要的应力在它的元素分布。如果元素不能补偿的操纵力，这些元素变得毫无用处，因为打破或大变形破坏。特别是叶片及传动元件必须耐用于操纵力下。应力分布的预测是非常重要的无故障产生的良好工作的设计和产品设计师和制造商。机的厂家，要为自己的机器，可能的错误，防止使用的材料，具有很高的安全系数，或者他们使用高质量的机械元件。虽然这些措施可以安全，产品的重量和成本的上升。
帮助开发的技术和设计软件，集成在新的代计算机，设计变得更加方便和可靠的。设计师可以设计在虚拟屏幕上自己的产品和他们可以利用计算机仿真技术，评价产品的工作条件。今天的三维（3D）与有限元法的应用中越来越广泛的建模工业。许多三维建模和有限元的应用实例可以在不同的工程学科（谷内，见1993）。
在这项研究中，一种旋耕机传动齿轮火车，这是由本地制造商制造，采用Solid Works三维参数化建模设计软件。三维建模后的程序，进行了模拟研究
在利用COSMOS Works有限元软件传动齿轮火车。旋耕机和第二齿轮箱传动轮系及其三维模型在图1中给出的。此外，图2显示了一个架构，是属于旋耕机传动系统（不同等人。，2005）。如下图所示架构的运动和动力的传递与拖拉机动力输出万向节连接到第一齿轮箱有2个螺旋锥齿轮的齿数的10和23，然后到第二齿轮箱轴。
2。材料和方法
2.1三维建模及应力分析
传动齿轮
根据齿轮传动齿轮的原尺寸模型，然后他们聚集。通过图3可以看到他们的3D 模型和它的值在表1中给出的。开始的应力分析，我们认为，在正常工作条件下工作的齿轮。
在耕作，与旋耕机的操作，所需的拖拉机动力输出功率为49.5千瓦拖拉机动力输出革命是540分钟，根据拖拉机动力输出功率和传动比的齿轮，时刻齿轮已经占用。
表1。传动齿轮的值
在模拟中，两种分析各齿轮副齿轮产生（I-II和齿轮II-III）对工作条件。分析了已生成的三维，静态和线性COSMOS Works有限元软件的假设。各向同性材料属性中使用的齿轮材料的模拟和性能的了表2（库塔，2003）。装配时，值得注意的是，在接触工作齿轮的齿，配对就在彼此接触条件下的单。因为，实验结果表明，对齿轮的表面发生的最大应力和失效对齿轮接触区和齿根单接触条件（库股，1993）。
表2。齿轮的材料特性
2.2齿轮1和齿轮II之间的应力分析
齿轮和齿轮II我组装后，施加边界条件。齿轮II固定于其轴轴承。占矩值法旋转轴方向的网格构造齿轮我在图4中可以看到。
COSMOS Works啮合的功能已被用于地图网格。高阶（二级）的抛物型固体四面体单元具有四个角节点，六中间节点，六边的高质量的网格划分功能（COSMOS 工程建设，2006）。
在啮合操作，共342160个元素和获得489339个节点的包含，总共对于啮合的齿轮1和齿轮II来说。
在求解过程中，应力分布如图5所示的了，对齿轮和齿轮II。作为一个结果的最大等效应力（von米塞斯），确定对齿轮工作齿的接触面为我和123.59 MPa，73.98 MPa时最大等效应力由齿轮工作齿II确定。
2.3齿轮II和齿轮III的应力分析
在这一部分中，同样的必要程序，应用应力分析齿轮II和齿轮 III施加边界条件，生成的网格划分和求解程序。齿轮III被固定在轴承和占力矩值应用于齿轮II。在啮合操作模型，总共有326600个元素468512总节点啮合齿轮II和III总齿轮（图6）。
结果图显示对齿轮II和III在图7齿轮。分析结果表明，最大等效应力发生在接触表面加工齿轮III为47.13 M Pa。根据施加的力矩46.37 M Pa的等效应力值对齿轮II齿面接触区发生工作。
得到的仿真结果表明，我们是如何工作的分布应力传动齿轮齿。根据仿真结果和齿轮材料的屈服应力，工作安全系数占传动齿轮（表3）。
表3。传动齿轮的工作安全系数
参考文献
耶尔马兹，博士，卡纳克基先生，2005。一种旋耕机齿轮失效。工程失效分析，12（3）：400～404。
2006软件COSMOS Works帮助文件，2006。COSMOS Works用户指南。
库股，1993。机械元件。科贾埃利大学出版社，第二卷，科贾埃利（土耳其）。
库塔，M.G.，2003。指导制造商。比尔深出版社，伊斯坦布尔（土耳其）。
谷内，D.，1993。有限元原理方法工程师。（翻译），萨卡里亚大学出版社，No.03，萨卡里亚（土耳其）。
奥美资，A.，2001。园林植物的机械化。阿克登尼基大学出版社：No.76，安塔利亚，（土耳其）。
STRESS ANALYSIS ON TRANSMISSION GEARS OF A ROTARY TILLER USING FINITE ELEMENT METHOD Mehmet TOPAKCI a H.Kursat CELIK Deniz YILMAZ Ibrahim AKINCI Akdeniz University, Faculty of Agriculture, Department of Agricultural Machinery,
Antalya, Turkey
Accepted 12 August 2008
Abstract:
Rotary tiller is one of the tillage tools which gets own motion from tractor power take off (PTO) and it had been designed for blend to soil. Soil traffic is decreased to great extent with this tool by blending the soil. Using of rotary tiller is increasing nowadays in our country because of its many benefits. Rotary tiller construction has a gear box that changes motion direction with 90 degrees from tractor PTO, transmission gears for rotation velocity and a rotor shaft which placed as horizontal to soil for blending. There are cutter blades on rotor shaft for breaking into pieces and blend to soil. Especially, on cutter blade and transmission gears, deformations occur because of high vibration, pointless high power, impact effect of soil parts, design-manufacturing error and wrong using conditions. Especially for construction and transmission parts, stress distributions should be determined well for understand failure reasons. In this study, transmission gear train of a rotary tiller which was designed and manufactured by a local manufacturer was modeled as three-dimensional in a parametric design software and structural stress distributions on transmission gears were simulated using a finite element method software according to its operating condition. After evaluating of simulation results, stress distributions on gears show that gears working without failure according to yield stress of gear’s materials. Additionally, working safety coefficient of gears calculated by reference simulation results.
Keywords: Rotary Tiller, Stress Analysis, Finite Elements Method
1. Introduction
Rotary tiller is a tillage machine which is used in arable field and fruit gardening agriculture. Rotary tiller has a huge capacity for cutting, mixing to topsoil and preparing the seedbed preparation directly. Additionally, a rotary tiller has more mixing capacity seven times than a plough ( Ozmerzi , 2002).
The rotary tiller is attached to three point linkage system of a tractor and it is driven by the tractor PTO (Power Take Off). The motion direction is changed as 90 degrees from tractor PTO to second gear box by horizontal shaft. The rotor shaft gets its motion from second gear box.
Rotary tiller’s elements work under miscellaneous forces because of high vibration, pointless high power, impact effect of soil parts, design-manufacturing errors and wrong using conditions in tillage operation. Therefore, undesired stress distributions occur on its elements. If the elements cannot compensate to the operating forces, these elements become useless because of breaking or high deformation failure. Especially blades and transmission elements have to be durable against to operating forces. Predicting to stress distributions is so important for the designers and manufacturers to generate good working designs and products without failure. Machine manufacturers, which want to prevent for probable errors
of their own machines, use materials, which have high safety coefficient, or they use high weight machine elements. Although these prevention methods can be safety, weight and cost of products rise.
Helping with developed technologies and design software which integrated in new generation computers, designs are getting easier and reliable. Designers can design own products in virtual screen and they can evaluate working condition of the products by simulating techniques using the computers. Today three-dimensional (3D) modeling and finite elements method applications are getting so widespread in the industry. Many of 3D modeling and finite elements application samples can be seen on different engineering disciplines (Gunay, 1993).
In this study, transmission gear train of a rotary tiller, which was designed and manufactured by a local manufacturer, was modeled using Solid works 3D parametric design software. After 3D modeling procedure, a simulation study was carried out on the transmission gear train using Cosmos works finite elements software. Rotary tiller and its second gear box transmission gear train and its 3D model were given in Figure 1. Additionally, Figure 2 shows a schema that is belong to transmission system of rotary tiller (Akinci et al., 2005). As shown in the schema that motion and power transmit with universal joint from tractor PTO output to first gear box that has 2 helical bevel gears which have 10 and 23 number of teeth and then goes to second gear box to rotor shaft.
2. Materials and Methods
2.1 3D Modeling and Stress Analysis of
Transmission Gears
Transmission gears were modeled according to original dimensions of gears then they were assembled. It can be seen in Figure 3 their 3D model and its values were given in Table 1. Getting started stress analysis, we assumed that gears are working in normal working condition. In the tillage
operation with rotary tiller, required tractor PTO power was taken as 49.5 kW
and tractor PTO revolution was 540 min According to tractor PTO power and transmission ratios, moments of gears have been accounted.
In simulation, two analyses generated for each two gear pairs (Gear I-II and Gear II-III) on working condition. Analyses have been generated in3D, static and linear assumptions in Cosmos works finite elements software. Isotropic material properties were used in simulation and properties of gear’s material was given at Table 2 (Kutay, 2003). While assembling, it was noted that working gear’s tooth in contact, paired
just at single contact condition with each others. Because, experiments show that maximum stresses and failures on gears occur on gear’s surface contact zone and tooth root on single contact condition (Curgul, 1993).
2.2 Stress Analysis Between on Gear I and Gear II
After assembling of Gear I and Gear II, boundary condition was applied. Gear II fixed from bearing of its shaft. Accounted moment value was applied at direction of rotation axis to Gear I and its mesh construction can be seen in Figure 4.
Cosmos works meshing functions have been used to map the meshing. Higher-order (Second-order) parabolic solid tetrahedral element which has four corner nodes, six mid-side nodes, and six edges attached by meshing function for high quality mesh construction (Cosmos Works, 2006).
After meshing operation, 342160 total elements and 489339 total nodes obtained for meshed Gear I and Gear II in total.
After solve process, stress distributions has been shown in Figure 5 for pairs of Gear I and Gear II. As a result maximum equivalent stress (Von Mises) determined on the contact surface of working teeth of Gear I as 123.59 M Pa and 73.98 M Pa maximum equivalent stresses determined on working teeth of Gear II.
2.3 Stress Analysis Between on Gear II and
Gear III
In this section, same necessary procedures are applied for stress analysis of Gear II and Gear III. Boundary conditions are applied, generated meshing and solve procedure. Gear III has been fixed on bearing and accounted moment value is applied to Gear II. After meshing operation models have 326600 total elements and 468512 total nodes for meshed Gear II and Gear III in total (Figure 6).
Result plots were showed for pairs of Gear II and Gear III in Figure 7. Analysis results show that maximum equivalent stress occurred on contact surface working teeth of Gear III as 47.13 M Pa. According to applied moment 46.37 M Pa equivalent stress value occurred on contact zone of working teeth of Gear II.
Obtained simulation results show us to how is distributing stresses on working teeth of transmission gears. According to simulation results and yield stress of gear’s
material, working safety coefficient accounted for transmission gears (Table 3).
3. Conclusions
In this study, stress distributions were simulated on transmission gears of a rotary tiller which designed and manufactured by local manufacturer. For this aim, transmission gears were modeled and structural stress analysis was generated using Solid works 3D parametric software and Cosmos works finite elements software. According to simulation results, following notes can be said;
1. When transmission gears were evaluated in the simulation results according to yield stress of gear’s material, no failur e was detected on gears. Gears are working on normal condition.
2. In stress analysis between Gear I and Gear II, maximum equivalent stress was determined on contact surface of working teeth of Gear I as 12
3.59 M Pa. In same results plot of Gear II working teeth has 73.98 M Pa stress value on contact surface.
3. In stress analysis between Gear II and Gear III, maximum equivalent stress was determined on contact surface of working teeth of Gear III as 47.13 M Pa. Maximum stress value was determined 46.37 M Pa on working teeth of Gear II contact surface.
4. According to simulation maximum stress results on gears, working safety coefficients are accounted for Gear I, Gear II and Gear III as shown Table 3.
To use materials which have high safety coefficients are looking easy and well applications for designers. But this way goes excessive cost rising, weight and time. Avoid for these results, using of simulation techniques and pc-software which are prepared for designers, are so useful tools and applications to gain time and manufacturing costs. In addition, it is possible to increase the quality and capacity of optimum machinery and tool design in agricultural mechanization systems.
References
Akinci. I, Yilmaz, D., ?anakci, M., 2005. Failure of a Rotary Tiller Spur Gear. Engineering failure analysis, 12(3): 400- 404.
Cosmos Works 2006 software help file, 2006. Cosmos Works user guide.
Curgul, ?., 1993. Machine Elements. University of Kocael i press ,Volume II, Kocaeli (In Turkish).
Kutay, M.G., 2003. Guide for Manufacturer. Birsen Press, Istanbul (In Turkish).
Gunay, D., 1993. Fundementals of Finite Element Method for
Engineers.(translation), Sakarya University, Press no:03, Sakarya (In Turkish).
Ozmerzi, A., 2001. Mechanization of Garden Plants. Akdeniz University, Press no:76, Antalya (In Turkish).
本科毕业设计文献综述范例(1)
###大学 本科毕业设计（论文）文献综述 课题名称： 学院（系）： 年级专业： 学生姓名： 指导教师： 完成日期：
燕山大学本科生毕业设计（论文） 一、课题国内外现状 中厚板轧机是用于轧制中厚度钢板的轧钢设备。在国民经济的各个部门中广泛的采用中板。它主要用于制造交通运输工具（如汽车、拖拉机、传播、铁路车辆及航空机械等）、钢机构件（如各种贮存容器、锅炉、桥梁及其他工业结构件）、焊管及一般机械制品等［1~3］。 1 世界中厚板轧机的发展概况 19世纪五十年代，美国用采用二辊可逆式轧机生产中板。轧机前后设置传动滚道，用机械化操作实现来回轧制，而且辊身长度已增加到2m以上，轧机是靠蒸汽机传动的。1864年美国创建了世界上第一套三辊劳特式中板轧机，当时盛行一时，推广于世界。1918年卢肯斯钢铁公司科茨维尔厂为了满足军舰用板的需求，建成了一套5230mm四辊式轧机，这是世界上第一套5m以上的轧机。1907年美国钢铁公司南厂为了轧边，首次创建了万能式厚板轧机，于1931年又建成了世界上第一套连续式中厚板轧机。欧洲国家中厚板生产也是较早的。1910年，捷克斯洛伐克投产了一套4500mm二辊式厚板轧机。1940年，德国建成了一套5000mm四辊式厚板轧机。1937年，英国投产了一套3810mm中厚板轧机。1939年，法国建成了一套4700mm 四辊式厚板轧机。这些轧机都是用于生产机器和兵器用的钢板，多数是为了二次世界大战备战的需要。1941年日本投产了一套5280mm四辊式厚板轧机，主要用于满足海军用板的需要。20世纪50年代，掌握了中厚板生产的计算机控制。20世纪80年代，由于中厚板的使用部门萧条，许多主要产钢国家的中厚板产量都有所下降，西欧国家、日本和美国关闭了一批中厚板轧机（宽度一般在3、4米以下）。国外除了大的厚板轧机以外，其他大型的轧机已很少再建。1984年底，法国东北方钢铁联营敦刻尔克厂在4300mm轧机后面增加一架5000mm宽厚板轧机，增加了产量，且扩大了品种。1984年底，苏联伊尔诺斯克厂新建了一套5000mm宽厚板轧机，年产量达100万t。1985年初，德国迪林冶金公司迪林根厂将4320mm轧机换成4800mm 轧机，并在前面增加一架特宽得5500mm轧机。1985年12月日本钢管公司福山厂新型制造了一套4700mmHCW型轧机，替换下原有得轧机，更有效地控制板形，以提高钢板的质量。 - 2 -
机械毕业设计英文外文翻译460数字控制 (2)
附录 科技译文： Numerical Control Numerical Control(NC) is a method of controlling the movements of machineComponents by directly inserting coded instructions in the form of numerical data(numbers and data ) into the system.The system automatically interprets these data and converts to output signals. These signals ,in turn control various machine components ,such as turning spindles on and off ,changing tools,moving the work piece or the tools along specific paths,and turning cutting fluits on and off. In order to appreciate the importer of numerical control of machines ,let’s briefly review how a process such as machining has been carried out traditionally .After studying the working drawing of a part, the operator sets up the appropriate process parameters(such as cutting speed ,feed,depth of cut,cutting fluid ,and so on),determines the sequence of operations to be performed,clamps the work piece in a workholding device such as chuck or collet ,and proceeds to make the part .Depending on part shape and the dimensional accuracy specified ,this approach usually requires skilled
机械专业毕业论文外文翻译
附录一英文科技文献翻译 英文原文： Experimental investigation of laser surface textured parallel thrust bearings Performance enhancements by laser surface texturing (LST) of parallel-thrust bearings is experimentally investigated. Test results are compared with a theoretical model and good correlation is found over the relevant operating conditions. A compari- son of the performance of unidirectional and bi-directional partial-LST bearings with that of a baseline, untextured bearing is presented showing the bene?ts of LST in terms of increased clearance and reduced friction. KEY WORDS: ?uid ?lm bearings, slider bearings, surface texturing 1. Introduction The classical theory of hydrodynamic lubrication yields linear (Couette) velocity distribution with zero pressure gradients between smooth parallel surfaces under steady-state sliding. This results in an unstable hydrodynamic ?lm that would collapse under any external force acting normal to the surfaces. However, experience shows that stable lubricating ?lms can develop between parallel sliding surfaces, generally because of some mechanism that relaxes one or more of the assumptions of the classical theory. A stable ?uid ?lm with su?cient load-carrying capacity in parallel sliding surfaces can be obtained, for example, with macro or micro surface structure of di?erent types. These include waviness [1] and protruding microasperities [2–4]. A good literature review on the subject can be found in Ref. [5]. More recently, laser surface texturing (LST) [6–8], as well as inlet roughening by longitudinal or transverse grooves [9] were suggested to provide load capacity in parallel sliding. The inlet roughness concept of Tonder [9] is based on ??e?ective clearance‘‘ reduction in the sliding direction and in this respect it is identical to the par- tial-LST concept described in ref. [10] for generating hydrostatic e?ect in high-pressure mechanical seals. Very recently Wang et al. [11] demonstrated experimentally a doubling of the load-carrying capacity for the surface- texture design by reactive ion etching of SiC
毕业设计外文翻译资料
外文出处： 《Exploiting Software How to Break Code》By Greg Hoglund, Gary McGraw Publisher : Addison Wesley Pub Date : February 17, 2004 ISBN : 0-201-78695-8 译文标题： JDBC接口技术 译文： JDBC是一种可用于执行SQL语句的JavaAPI（ApplicationProgrammingInterface应用程序设计接口）。它由一些Java语言编写的类和界面组成。JDBC为数据库应用开发人员、数据库前台工具开发人员提供了一种标准的应用程序设计接口，使开发人员可以用纯Java语言编写完整的数据库应用程序。 一、ODBC到JDBC的发展历程 说到JDBC，很容易让人联想到另一个十分熟悉的字眼“ODBC”。它们之间有没有联系呢？如果有，那么它们之间又是怎样的关系呢？ ODBC是OpenDatabaseConnectivity的英文简写。它是一种用来在相关或不相关的数据库管理系统（DBMS）中存取数据的，用C语言实现的，标准应用程序数据接口。通过ODBCAPI，应用程序可以存取保存在多种不同数据库管理系统（DBMS）中的数据，而不论每个DBMS使用了何种数据存储格式和编程接口。 1．ODBC的结构模型 ODBC的结构包括四个主要部分：应用程序接口、驱动器管理器、数据库驱动器和数据源。应用程序接口：屏蔽不同的ODBC数据库驱动器之间函数调用的差别，为用户提供统一的SQL编程接口。 驱动器管理器：为应用程序装载数据库驱动器。 数据库驱动器：实现ODBC的函数调用，提供对特定数据源的SQL请求。如果需要，数据库驱动器将修改应用程序的请求，使得请求符合相关的DBMS所支持的文法。 数据源：由用户想要存取的数据以及与它相关的操作系统、DBMS和用于访问DBMS的网络平台组成。 虽然ODBC驱动器管理器的主要目的是加载数据库驱动器，以便ODBC函数调用，但是数据库驱动器本身也执行ODBC函数调用，并与数据库相互配合。因此当应用系统发出调用与数据源进行连接时，数据库驱动器能管理通信协议。当建立起与数据源的连接时，数据库驱动器便能处理应用系统向DBMS发出的请求，对分析或发自数据源的设计进行必要的翻译，并将结果返回给应用系统。 2．JDBC的诞生 自从Java语言于1995年5月正式公布以来，Java风靡全球。出现大量的用java语言编写的程序，其中也包括数据库应用程序。由于没有一个Java语言的API，编程人员不得不在Java程序中加入C语言的ODBC函数调用。这就使很多Java的优秀特性无法充分发挥，比如平台无关性、面向对象特性等。随着越来越多的编程人员对Java语言的日益喜爱，越来越多的公司在Java程序开发上投入的精力日益增加，对java语言接口的访问数据库的API 的要求越来越强烈。也由于ODBC的有其不足之处，比如它并不容易使用，没有面向对象的特性等等，SUN公司决定开发一Java语言为接口的数据库应用程序开发接口。在JDK1．x 版本中，JDBC只是一个可选部件，到了JDK1．1公布时，SQL类包（也就是JDBCAPI）
毕业设计外文翻译附原文
外文翻译 专业机械设计制造及其自动化学生姓名刘链柱 班级机制111 学号1110101102 指导教师葛友华
外文资料名称： Design and performance evaluation of vacuum cleaners using cyclone technology 外文资料出处：Korean J. Chem. Eng., 23(6), (用外文写) 925-930 (2006) 附件： 1.外文资料翻译译文 2.外文原文
应用旋风技术真空吸尘器的设计和性能介绍 吉尔泰金，洪城铱昌，宰瑾李， 刘链柱译 摘要：旋风型分离器技术用于真空吸尘器 - 轴向进流旋风和切向进气道流旋风有效地收集粉尘和降低压力降已被实验研究。优化设计等因素作为集尘效率，压降，并切成尺寸被粒度对应于分级收集的50％的效率进行了研究。颗粒切成大小降低入口面积，体直径，减小涡取景器直径的旋风。切向入口的双流量气旋具有良好的性能考虑的350毫米汞柱的低压降和为1.5μm的质量中位直径在1米3的流量的截止尺寸。一使用切向入口的双流量旋风吸尘器示出了势是一种有效的方法，用于收集在家庭中产生的粉尘。 摘要及关键词：吸尘器; 粉尘; 旋风分离器 引言 我们这个时代的很大一部分都花在了房子，工作场所，或其他建筑，因此，室内空间应该是既舒适情绪和卫生。但室内空气中含有超过室外空气因气密性的二次污染物，毒物，食品气味。这是通过使用产生在建筑中的新材料和设备。真空吸尘器为代表的家电去除有害物质从地板到地毯所用的商用真空吸尘器房子由纸过滤，预过滤器和排气过滤器通过洁净的空气排放到大气中。虽然真空吸尘器是方便在使用中，吸入压力下降说唱空转成比例地清洗的时间，以及纸过滤器也应定期更换，由于压力下降，气味和细菌通过纸过滤器内的残留粉尘。 图1示出了大气气溶胶的粒度分布通常是双峰形，在粗颗粒（>2.0微米）模式为主要的外部来源，如风吹尘，海盐喷雾，火山，从工厂直接排放和车辆废气排放，以及那些在细颗粒模式包括燃烧或光化学反应。表1显示模式，典型的大气航空的直径和质量浓度溶胶被许多研究者测量。精细模式在0.18?0.36 在5.7到25微米尺寸范围微米尺寸范围。质量浓度为2?205微克，可直接在大气气溶胶和 3.85至36.3μg/m3柴油气溶胶。
毕业设计文献综述范文
四川理工学院毕业设计（文献综述）红外遥控电动玩具车的设计 学生：程非 学号：10021020402 专业：电子信息工程 班级：2010.4 指导教师：王秀碧 四川理工学院自动化与电子信息学院 二○一四年三月
1前言 1.1 研究方向 随着科技的发展，越来越多的现代化电器走进了普通老百姓的家庭，而这些家用电器大都由红外遥控器操控，过多不同遥控器的混合使用带来了诸多不便。因此，设计一种智能化的学习型遥控器，学习各种家用电器的遥控编码，实现用一个遥控器控制所有家电，已成为迫切需求。首先对红外遥控接收及发射原理进行分析，通过对红外编码理论的学习，设计以MSP430单片机为核心的智能遥控器。其各个模块设计如下：红外遥控信号接收，红外接收器把接收到的红外信号经光电二极管转化成电信号，再对电信号进行解调，恢复为带有一定功能指令码的脉冲编码；接着是红外编码学习，利用单片机的输入捕捉功能捕捉载波的跳变沿，并通过定时器计时记下载波的周期和红外信号的波形特征，进行实时编码；存储电路设计，采用I2C总线的串行E2PROM(24C256)作为片外存储器，其存储容量为8192个字节，能够满足所需要的存取需求；最后是红外发射电路的设计，当从存储模块中获取某红外编码指令后，提取红外信号的波形特征信息并进行波形还原；将其调制到38KHZ的载波信号上，通过三极管放大电路驱动红外发光二极管发射红外信号，达到红外控制的目的。目前，国外进口的万能遥控器价格比较昂贵，还不能真正走进普通老百姓的家中。本文在总结和分析国外设计的基础上，设计一款以MSP430单片机为核心的智能型遥控器，通过对电视机和空调的遥控编码进行学习，能够达到预期的目的，具有一定的现实意义。 1.2 发展历史 红外遥控由来已久，但是进入90年代，这一技术又有新的发张，应用范围更加广泛。红外遥控是一种无线、非接触控制技术，具有抗干扰能力强，信息传输可靠，功耗低，成本低，易实现等显著优点，被诸多电子设备特别是家用电器广泛采用，并越来越多的应用到计算机系统中。 60年代初，一些发达国家开始研究民用产品的遥控技术，单由于受当时技术条件限制，遥控技术发展很缓慢，70年代末，随着大规模集成电路和计算机技术的发展，遥控技术得到快速发展。在遥控方式上大体经理了从有线到无限的超声波，从振动子到红外线，再到使用总线的微机红外遥控这样几个阶段。无论采用何种方式，准确无误传输新信号，最终达到满意的控制效果是非常重要的。最初的无线遥控装置采用的是电磁波传输信号，由于电磁波容易产生干扰，也易受干扰，因此逐渐采用超声波和红外线媒介来传输信号。与红外线相比，超声传感器频带窄，所能携带的信息量少扰而引起误动作。较为理想的是光控方式，逐渐采用红外线的遥控方式取代了超声波遥控方式，出现了红外线多功能遥控器，成为当今时代的主流。 1.3 当前现状 红外线在频谱上居于可见光之外，所以抗干扰性强，具有光波的直线传播特性，不易产生相互间的干扰，是很好的信息传输媒体。信息可以直接对红外光进行调制传输，例如，信息直接调制红外光的强弱进行传输，也可以用红外线产生一定频率的载波，再用信息对载波进调制，接收端再去掉载波，取到信息。从信
机械毕业设计英文外文翻译204机电一体化
附录 INTEGRATION OF MACHINERY （From ELECTRICAL AND MACHINERY INDUSTRY）ABSTRACT Machinery was the modern science and technology development inevitable result, this article has summarized the integration of machinery technology basic outline and the development background .Summarized the domestic and foreign integration of machinery technology present situation, has analyzed the integration of machinery technology trend of development. Key word：integration of machinery ，technology，present situation ，product t，echnique of manufacture ，trend of development 0. Introduction modern science and technology unceasing development, impelled different discipline intersecting enormously with the seepage, has caused the project domain technological revolution and the transformation .In mechanical engineering domain, because the microelectronic technology and the computer technology rapid development and forms to the mechanical industry seepage the integration of machinery, caused the mechanical industry the technical structure, the product organization, the function and the constitution, the production method and the management system has had the huge change, caused the industrial production to enter into “the integration of machinery” by “the machinery electrification” for the characteristic development phase. 1. Integration of machinery outline integration of machinery is refers in the organization new owner function, the power function, in the information processing function and the control function introduces the electronic technology, unifies the system the mechanism and the computerization design and the software which constitutes always to call. The integration of machinery development also has become one to have until now own system new discipline, not only develops along with the science and technology, but also entrusts with the new content .But its basic characteristic may summarize is: The integration of machinery is embarks from the system viewpoint, synthesis community technologies and so on utilization mechanical technology, microelectronic technology, automatic control technology,
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
毕业设计英文翻译
使用高级分析法的钢框架创新设计 1．导言 在美国，钢结构设计方法包括允许应力设计法(ASD)，塑性设计法(PD)和荷载阻力系数设计法(LRFD)。在允许应力设计中，应力计算基于一阶弹性分析，而几何非线性影响则隐含在细部设计方程中。在塑性设计中，结构分析中使用的是一阶塑性铰分析。塑性设计使整个结构体系的弹性力重新分配。尽管几何非线性和逐步高产效应并不在塑性设计之中，但它们近似细部设计方程。在荷载和阻力系数设计中，含放大系数的一阶弹性分析或单纯的二阶弹性分析被用于几何非线性分析，而梁柱的极限强度隐藏在互动设计方程。所有三个设计方法需要独立进行检查，包括系数K计算。在下面，对荷载抗力系数设计法的特点进行了简要介绍。 结构系统内的内力及稳定性和它的构件是相关的，但目前美国钢结构协会（AISC）的荷载抗力系数规范把这种分开来处理的。在目前的实际应用中，结构体系和它构件的相互影响反映在有效长度这一因素上。这一点在社会科学研究技术备忘录第五录摘录中有描述。 尽管结构最大内力和构件最大内力是相互依存的（但不一定共存），应当承认，严格考虑这种相互依存关系，很多结构是不实际的。与此同时，众所周知当遇到复杂框架设计中试图在柱设计时自动弥补整个结构的不稳定（例如通过调整柱的有效长度）是很困难的。因此，社会科学研究委员会建议在实际设计中，这两方面应单独考虑单独构件的稳定性和结构的基础及结构整体稳定性。图28.1就是这种方法的间接分析和设计方法。
在目前的美国钢结构协会荷载抗力系数规范中，分析结构体系的方法是一阶弹性分析或二阶弹性分析。在使用一阶弹性分析时，考虑到二阶效果，一阶力矩都是由B1,B2系数放大。在规范中，所有细部都是从结构体系中独立出来，他们通过细部内力曲线和规范给出的那些隐含二阶效应，非弹性，残余应力和挠度的相互作用设计的。理论解答和实验性数据的拟合曲线得到了柱曲线和梁曲线，同时Kanchanalai发现的所谓“精确”塑性区解决方案的拟合曲线确定了梁柱相互作用方程。 为了证明单个细部内力对整个结构体系的影响，使用了有效长度系数，如图28.2所示。有效长度方法为框架结构提供了一个良好的设计。然而，有效长度方法的
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
毕业设计外文翻译
毕业设计（论文） 外文翻译 题目西安市水源工程中的 水电站设计 专业水利水电工程 班级 学生 指导教师 2016年
研究钢弧形闸门的动态稳定性 牛志国 河海大学水利水电工程学院，中国南京，邮编210098 nzg_197901@https://www.360docs.net/doc/2216578112.html,，niuzhiguo@https://www.360docs.net/doc/2216578112.html, 李同春 河海大学水利水电工程学院，中国南京，邮编210098 ltchhu@https://www.360docs.net/doc/2216578112.html, 摘要 由于钢弧形闸门的结构特征和弹力，调查对参数共振的弧形闸门的臂一直是研究领域的热点话题弧形弧形闸门的动力稳定性。在这个论文中，简化空间框架作为分析模型，根据弹性体薄壁结构的扰动方程和梁单元模型和薄壁结构的梁单元模型，动态不稳定区域的弧形闸门可以通过有限元的方法，应用有限元的方法计算动态不稳定性的主要区域的弧形弧形闸门工作。此外，结合物理和数值模型，对识别新方法的参数共振钢弧形闸门提出了调查，本文不仅是重要的改进弧形闸门的参数振动的计算方法，但也为进一步研究弧形弧形闸门结构的动态稳定性打下了坚实的基础。 简介 低举升力，没有门槽，好流型，和操作方便等优点，使钢弧形闸门已经广泛应用于水工建筑物。弧形闸门的结构特点是液压完全作用于弧形闸门，通过门叶和主大梁，所以弧形闸门臂是主要的组件确保弧形闸门安全操作。如果周期性轴向载荷作用于手臂，手臂的不稳定是在一定条件下可能发生。调查指出:在弧形闸门的20次事故中，除了极特殊的破坏情况下，弧形闸门的破坏的原因是弧形闸门臂的不稳定;此外，明显的动态作用下发生破坏。例如:张山闸，位于中国的江苏省，包括36个弧形闸门。当一个弧形闸门打开放水时，门被破坏了，而其他弧形闸门则关闭，受到静态静水压力仍然是一样的，很明显，一个动态的加载是造成的弧形闸门破坏一个主要因素。因此弧形闸门臂的动态不稳定是造成弧形闸门(特别是低水头的弧形闸门)破坏的主要原是毫无疑问。
本科毕业设计方案外文翻译范本
I / 11 本科毕业设计外文翻译 <2018届） 论文题目基于WEB 的J2EE 的信息系统的方法研究 作者姓名[单击此处输入姓名] 指导教师[单击此处输入姓名] 学科(专业 > 所在学院计算机科学与技术学院 提交日期[时间 ]
基于WEB的J2EE的信息系统的方法研究 摘要：本文介绍基于工程的Java开发框架背后的概念，并介绍它如何用于IT 工程开发。因为有许多相同设计和开发工作在不同的方式下重复，而且并不总是符合最佳实践，所以许多开发框架建立了。我们已经定义了共同关注的问题和应用模式，代表有效解决办法的工具。开发框架提供：<1）从用户界面到数据集成的应用程序开发堆栈；<2）一个架构，基本环境及他们的相关技术，这些技术用来使用其他一些框架。架构定义了一个开发方法，其目的是协助客户开发工程。 关键词：J2EE 框架WEB开发 一、引言 软件工具包用来进行复杂的空间动态系统的非线性分析越来越多地使用基于Web的网络平台，以实现他们的用户界面，科学分析，分布仿真结果和科学家之间的信息交流。对于许多应用系统基于Web访问的非线性分析模拟软件成为一个重要组成部分。网络硬件和软件方面的密集技术变革[1]提供了比过去更多的自由选择机会[2]。因此，WEB平台的合理选择和发展对整个地区的非线性分析及其众多的应用程序具有越来越重要的意义。现阶段的WEB发展的特点是出现了大量的开源框架。框架将Web开发提到一个更高的水平，使基本功能的重复使用成为可能和从而提高了开发的生产力。 在某些情况下，开源框架没有提供常见问题的一个解决方案。出于这个原因，开发在开源框架的基础上建立自己的工程发展框架。本文旨在描述是一个基于Java的框架，该框架利用了开源框架并有助于开发基于Web的应用。通过分析现有的开源框架，本文提出了新的架构，基本环境及他们用来提高和利用其他一些框架的相关技术。架构定义了自己开发方法，其目的是协助客户开发和事例工程。 应用程序设计应该关注在工程中的重复利用。即使有独特的功能要求，也
机械毕业设计外文翻译---装载机发展概况
外文资料翻译 学生姓名： 专业班级：机械设计制造及其自动化04级2班指导教师： 2008年6月
装载机发展概况 Abstract This paper have discussed s.s. ZL-50 type fork-lift truck mainly overall fictitious prototype design as well as some kinds of typical schoolwork operating modes imitate and emulate , include equipment and the overall parts needed build mould. In this design course, have applied ADAMS software and the software of PRO/ENGINEER. ADAMS software is used in the emulation of some kinds of schoolwork operating modes, and the software of PRO/ENGINEER is used to build mould mainly. Through the simulated emulation for some kinds of overall schoolwork operating modes, can see relatively distinctly the overall possible condition in actual schoolwork course that met , can in time modify , have reduced actual design time , have raised production efficiency. The innovation of this design Zhi is in in, imitate and have emulated fork-lift truck the 3 kinds of typical schoolwork operating mode in actual schoolwork, is effect again have imitated in actual schoolwork the hydraulic impact of use, so when being helpful to solve actual loading, the actual problem of meeting the stock that is hard to uninstall can so raise production efficiency. Key words: Fork-lift truck 、fictitious prototype , build mould, emulation, optimization、production efficiency Loader Development China's modern 20 wheel loaders began in the mid-1960s of the Z435. The aircraft as a whole rack, rear axle steering. After years of hard work, the attraction was the world's most advanced technology wheel loader on the basis of the successful development of the power of 162 KW of shovel-fit wheel loaders, stereotypes for Z450 (later ZL50), and in 1971 December 18, formally appraised by experts. Thus the birth of China's first articulated wheel loader, thus creating our industry loader formation and development history. Z450-type loader with hydraulic mechanical transmission, power shift, Shuangqiaoshan drive, hydraulic manipulation, articulated power steering, gas oil Afterburner brake wheel loaders, and other modern, the basic structure of the world's advanced level for the time . Basically represent the first generation of wheeled loading the basic structure. The aircraft in the overall performance of dynamic, and insertion force a rise of power and flexibility, manipulation of light, the higher operating efficiency of a series of advantages. 1978, Heavenly Creations by the Department in accordance with the requirements of machinery, worked out to LIUGONG Z450-based type of wheel loaders series of standards. The development of standards, with reservations Z