机械设计外文翻译5
外文翻译
机械设计
摘要
机器是机构与其他零件的组合，为了有益的用途而转换、传递或利用能量、力或者运动实例有发动机、涡轮、车辆、卷扬机、印刷机、洗衣机和电影摄影机.许多适用于机器设计的原理和力法也适用于不是真正机器的制成品，从轮毂盖和档案橱柜到仪表和核压力容器。“机械设计”这一术语比“机器设计”更为广义，它包括机器设计。而对于某些仪器，如用以确定热、流动线路和体积的热力以及流体方面的问题要单独考虑。但是，在机械设计时要考虑运动和结构方面的问题以及保存和封装的规定。在机械工程领域以及其他工程领域应用机械设计，都需要诸如开关、凸轮、阀门、容器和搅拌器等机械装置。
关键词：机械设计机构设计过程工差
设计过程
设计始于真正的或想象的需要。现有的仪器可能需要在耐用性、效率、重量、速度或成本上加以改进。可能需要新的仪器来完成以前由人做的功能，如装配或保养。目标全部或部分地确定后，设计的下一步就是构思能够完成所需功能的机构及其布置为此，徒手画草图价值极大，它不但作为一个人想法的记录和与其他人讨论的辅助手段，
而且尤其适于与自己的想法交流，作为创造性思路的兴奋剂还需要有关于部件的广泛知识，因为一台新机器常常由熟知的各类零件重新安排或替换而成，也许改变了尺寸和材料。无论在构思过程中还是之后，一个设计者都会进行快速或粗略的计算或分析以确定一般尺寸和可
行性。当些关于所需或可用空间量的想法确定后，可以开始按比例画草图。
最后，一项基于功能和可靠性的设计完成了，就可以制造样机了。如果测试满意，而且如果装置要大量生产，就要对最初的设计进行一定的修改以确保以较低成本大量生产。在随后几年的制造和使用期间，设计有可能因构思了新想法或者基于测试和经验基础上的进一步分
析所显示的改变而改变。销售吸引力、客户满意度和制造成本都与设计有关，设计能力与工程投资的成功密切相关。
一些设计准则
在这一部分，有人建议运用创造性的态度进行的分析，这种分析可以引起重大改进以及对备用产品的构思和完善，也许产品功能更多、更经济、更耐用。创造阶段无须是最初和独立的阶段。虽然分析人员可能并不负责整个设计，但是他不仅仅是能从数字上提出要他解决的问题的正确答案，不仅仅是给出应力值、尺寸或者工作限制。他可以提出更广泛的见解，以便改进规范或方案。由于在分析前或分析过程中，他会熟悉装置及其工作条件，他就处于一个构思备选方案的有利位置。最好他能提出建议改变形状来消除力矩或应力集中，而不是允
许构建具有大截面和过多动态载荷的机构最好是他报废他的细致的设计而不是后来看到机械报废。
为了激发创造性思维，建议设计人员和分析人员使用以下准则。前6条准则尤其适用于分析人员，虽然他可能涉及到所有这10项。
1.创造性地利用所需的物理性能并控制不需要的。
2.认识实用载荷及其重要性。
3.预先考虑没有作用的载荷。
4.发明更有利的加载条件。
5.提供最小重量的最有利的应力分布和刚性。
6.用基本方程计算比例并使尺寸最优化。
7.选取材料以获得性能组合。
8.在备件和集成零件间仔细选择。
9.修改功能设计以适应生产过程和降低成本。
10.考虑装配中使部件精确定位和互不干扰。
机械设计
整个机械设计是一个复杂的过程。设计人员必须在这样的领域，如静力学、运动学、动力学和材料力学具有良好的素养，此外，还必须熟悉制造材料和制造工艺。设计人员必须能够组合所有相关的事实，进行训渭、制作草图和制图来把制造要求传递到车间。
任何产品设计的第一步工作之一是选择用于制造每个部件的材料。今天的设计人员可得到无数的。在选择时，产品的功能、外观、材料成本和制造成本都很重要。在任何计算之前必须仔细评估材料的性能。有必要仔细计算以确保设计的有效性.计算从不出现在图上,而是
由十各种原因被存起来。一旦任何一个部件失效，就要弄清楚在最初设计这个有缺陷的零件时做了什么；而且，从对过去的项目的计算中可以获得一份经验文件。当需要类似的设计时，过去的记录会有极大的帮助。
计算（和图上尺寸）的检查最为重要。一个小数点放错位置可以毁掉一个本来可以接受的项目。例如，如果一个人要设计一个能支撑100磅的托架，而它本应该能支撑1000磅，结果肯定会失败。必须
检查再检查设计工作的方方面面。
计算机对于工作人员来讲是一个很有用的工具，可以减轻乏味的计算并且对现有数据提供扩展分析。基于计算机性能的交互系统使计算机辅助设计（CAD）和计算机辅助制造（CAM)成为可能。通过这样的
系统，就可能把一个初步构思传送到打孔纸带用于数字加工控制而无须绘制正式的施工图。
实验室测试、模型和样机对于机械设计很有帮助。实验室提供了很多建立基本概念所需的信息，然而，还可用它们获得一些关于产品在现场会如何工作的认识
最后，一个成功的设计人员应尽最大努力跟上时代步伐。每天都会出现新材料和生产方法。绘图和设计人员如果不熟悉现代方法和材料就可能失去作用。一个好的设计人员应经常阅读技术期刊以跟上新的发展
工程工差
固体由其表面边界确定界限。典型地，设计人员给一个零件指定公称尺寸以使其满足其需要。实际上由于表面不规则以及固有的表面粗糙度，各个零件不能重复地做成公称尺寸必须允许尺寸有一些变化以确保能够制造。但是，所允许的变化一定不能太大以至于使装配件的性能变差。单个零件所允许的变化称为公差。
公差这一术语不仅适用于由制造工艺产生的部件尺寸的可以接受的范围，而且适用于机械或加工的输出。例如，一个给定型号的内燃机的功率每台都有所变化。实际上，我们常常发现这种变化模型会是频率分布曲线，例如t.态分布（又叫高斯分布）。设计人员的工作
之一就是给一个零件指定尺寸和允许的变化，这个值能够产生可以接受的性能。
零件公差
当图中没有指定确切尺寸时，大多数组织都有适用于尺寸的通用公差。对于加工尺寸，通用公差可能是±0.5毫米。因此，被指定为15.0毫米的尺寸的范围可以是14.5毫米到15.5毫米之间。其他通用公差可以适用于如角度、钻孔和冲孔，铸件、锻件、焊缝和焊角等情形。在给一个零件指定公差时，可以参考以前的图或一般的工程实践。典型的公差被指定为英武成JSO标准所定义的幅度。对于一个给定公差，比如H7/s6，对于正在研究的零件尺寸就有一组与图表对应的数值可用。下面这段将给出关于装入孔内的轴或柱形配合的具体例子。孔和轴的标准配合
一项标准的工程工作是确定一个柱形零件的公差，比如安装在一个相应的筒形零件或孔内的．或者是在其内部旋转的轴配合的松紧取决于应用例如，一个定位在轴上的齿轮就需要“紧”的静配合，这里轴的直径实际上比齿轮毅的内径稍微大一些以便能传递所需的扭矩。再者，滑动轴承的直径必须大于轴的直径以使其旋转。假定从经济上讲不能把部件制造成精确的尺寸，轴和孔尺寸上的大小变化就必须确定。但是，变化的范围不应太大以免装配时受损
为了不至于有无穷无尽的被指定的公差尺寸，已经制定了国家和国际标准确定了公差带，比如hll/cll。为了使用这一资料，给出了传统公差使用中的定义。通常使用的是基孔制，因为这会使公司内部所需的钻头、绞刀、拉刀和计量工具种类的减少。
尺寸：以专用单位表示尺寸数字值的数。
实际尺寸：通过测量得到的部件尺寸。
尺寸极限：零件允许的最大和最小尺寸。
最大尺寸极限：两个尺寸极限中较大的。
最小尺寸极限：两个尺寸极限中较小的
基本尺寸：用以固定尺寸极限的参考尺寸
偏差：一个尺寸与其对应的基本尺寸的代数差
实际偏差：实际尺寸与其对应的基本尺寸的代数差。
上偏差：最大尺寸极限与其对应的基本尺寸的代数差
下偏差：最小尺寸极限与其对应的基本尺寸的代数差
公差：最大尺寸极限与最小尺寸极限的差值。
轴：指定一个部件所有外部特征的惯用术语
孔：指定一个部件所有内部特征的惯用术语。
初步设计产生满足指定需求的解决方案。初步设计可以代表组成整个系统的所有子系统和零部件的总和。Ion和Smith把初步设计描述为由一系列形成和评估阶段组成的一个反复的过程，各阶段合在一起形成好的解决方案。在反复的每一阶段，构思更加详细，可以更全面的评估。
产生尽可能多的或经济便利的构思和想法是重要的。有一种诱惑，让你接受第一个有希望的构思并进行详细的设计直到最终产品。应该抵抗这种诱惑，因为这样结果总会更好些。值得一提的是，或早或晚你的设计会不得不与那些来自其他制造商的设计竞争，因此产生研制的思想应谨慎。
产生了想法和构思后，下一步就是对它们进行评估并选择最佳构思．一种评估方法是使用列表矩阵。矩阵由一系列准则组成．构思必须借助它们打分。如果合适，准则的重要性可以加权，最适合的构思会具有最高总分。这一方法提供了组织的评估技术．而且使团队内的个人很难推行他们自己的不合理的想法。
产生了初步的解决方案，下一步就是表达它们，以便它们能与所有涉及总体设计过程的人交流实际上，这一步可以采用绘制草图或三维模型的形式，既可是物理模型也可是计算机生成的模型。到总草图己
经完成并进行计算来确定解决方案对于产品设计规范的兼容性时，细节设计阶段的基础就已建立起来了。
Mechanical Design
Abstract:
A machine is a combination of mechanisms and other components which transforms, transmits, or utilizes energy, force, or motion for a useful purpose. Examples are engines, turbines, vehicles, hoists, printing presses, washing machines, and movie cameras. Many of the principles and methods of design that apply to machines also apply to manufactured articles that are not true machines, from hub caps and filing cabinets to instruments and nuclear pressure vessels. The term "mechanical design" is used in a broader sense than "machine design" to include their design. For some apparatus, the thermal and fluid aspects that determine the requirements of heat, flow path, and volume are separately considered. However, the motion and structural aspects and the provisions for retention and enclosure are considerations in mechanical design. Applications occur in the field of mechanical engineering, and in other engineering fields as well, all of which require mechanical devices, such as switches, cams, valves, vessels, and mixers.
Keywords: Mechanical Designmechanisms Design Process Tolerance
Design process
The design begins from real of or the demand of imagination.The existing instrument may need to take in to improve on the enduring, efficiency, weight, speed or the cost.May need new instrument to complete before function done by person, such as Assemble or maintain.The target is all or partly after making sure, design of the next move is to conceive outline the organization that can complete the function needed and it arranges for this, drawing grass diagram to be worth barehanded biggest, it isn't only one personal record of viewpoint with with others discussion of assistance means, and be suitable for to communicate with own viewpoint particularly, is the stimulant which creates sex way of thinking to still need extensive knowledge concerning parts, because a the set new machine usually from be familiar with of each kind of spare
parts reschedule or substitute but become, changed size and material
perhaps.Regardless at conceive outline process in still after, a design will carry on a fast or rough calculation or analyze to make sure regulation size and possibility.When some concerning need or can use amount of space of viewpoint assurance after, can start pro rata painting grass diagram.
Finally, 1 completed according to the design of the function and the credibility, can make kind machine.If test satisfied, and if the device wants mass production, will to the first design carry on a certain modification to insure with lower cost
https://www.360docs.net/doc/e19834363.html,ter on several years of make and use a period, design probably because of conceive outline new viewpoint perhaps according to test and experience foundation of further analytical the change shown but change.Sell attraction, customer's satisfaction and manufacturing costs to all have something to do with design, the success which designs ability and engineering investment is closely related.
Some design standards
At this part, someone suggests the attitude of the usage creation carries on of analysis, this kind of analysis can cause a graveness improvement and to back up the product conceive outline with perfect, perhaps the product function is more, more economic and more enduring.Creating the stage's needing not is first with independent stage.Although analyze personnel the whole probably irresponsible design, he isn't only the right answer of[with] problem that can be from the numeral put forward wanting him to resolve only, not only only is give should dint value, the size works to limit perhaps.He can put forward more extensive views, for the purpose of improvement norm or project.Because in the analysis the front or the analysis the process, he will acquaint with to equip and its work condition, he is fully placed in a beneficial position which conceives outline to choose a project.Best he can put forward a suggestion change shape to Elimination moment of force or should dint concentration, not allow to set up to have to cut the organization that noodles and excessive dynamic state carry a lotus greatly best is he discards his meticulous of design but is not see a machine discard afterwards.
For stiring up to create sex thinking, the suggestion designs a personnel and analytical the personnel use following standard.6 ex- standards are particularly applicable to an analysis personnel, although he may involve to all this 10.
1.Create the physical function that sex land utilization need when using combine the control don't need.
2.Know practical carry lotus and its importance.
3.Consider in advance there is no function carrying a lotus.
4.Invent to add to carry a condition more beneficially.
5.Provide minimum weight the most beneficial of distribute in response to the dint with rigid.
https://www.360docs.net/doc/e19834363.html,e a basic and square distance calculation a comparison and make size superior to turn.
7.Select by examinations material to acquire a function combination.
8.At spare parts and integrated spare parts careful choice.
9.Modify a function design with the orientation production line and decline low cost.
10.Consider to make parts accurate to position in the assemble with with each other not interference
Mechanical Design
The whole machine design is a complicated process.Designing the personnel have to at thus of realm, such as calm down mechanics, kinetics, dynamics and material mechanics have good cultivated manners, have to also acquaint with manufacturing material and make a craft in addition.Designing the personnel has to can combine all related facts, carrying on Teaches Wei and creating grass diagram and graphics to come to deliver the manufacturing request to the car.
The square one that any product designs works it an is the material that the choice useds for making each parts.The design personnel of today can get an innumerable.While choosing, function, external appearance, material cost and manufacturing costs of product are all very important.Had to be careful to evaluate the function of material before any calculation.
It is necessary a careful calculation with the usefulness of insuring the
https://www.360docs.net/doc/e19834363.html,pute to never appear on the diagram, but from ten various reason be saved.Once the whichever parts loses efficacy, will clear up to do what while designing this defective spare parts at the beginning;And, can acquire an experience document from compute past item.While needing the design for ising similar to, the past record will have a tremendous help.
The check of computing(with diagram top size) is the most important.A decimal point's mislaying position can ruin an original and acceptable item.For example, if a person wants to design a bracket that can prop up 100 pounds, but it should can prop up 1000 pounds originally, the result affirmation will fail.The square aspect noodles had to check a check to design again a work.
The calculator speaks to is an of great use tool for the staff member, can ease a dull calculation and provide to expand analysis to the existing data.Hand over system to make the calculator assistance design(CAD) with each other according to the calculator function and the calculator lend support to a manufacturing(CAM) to make possible.Pass thus of system, may conceive outline a first step to deliver to beat bore paper to take to used for numeral to process control but need not to draw formal construction diagram.
The machine design for the laboratory test, model and kind machine is very helpful.The laboratory provided a lot of build up basic concept need of information, however, can also acquire with them some concerning product how on the spot would the understanding for working.
Finally, a design personnel of success should offer the step that the utmost effort keeps up with ages.Will appear new material and produce a method everyday.If painting and design personnel's don't acquainting with modern method and material may put out action.A good design personnel should usually read technique periodical to keep up with a new development
The engineering work is bad
The solid is made sure boundary by its surface boundary.Typical model ground, design a personnel to specify Mr. to call size to a spare parts to make it contented its demand.Actually because of the surface irregular and proper surface rough degree,
each spare parts can't make into Mr. to call size's hasing to allow size to have some varieties can make with insuring repeatedly.But, the variety allowed can't certainly too big with as for make to assemble the function of the piece to become bad.Single the variety allowed by spare parts is called business trip.
Business trip this technical term not only is applicable to from the acceptable scope of the parts size of[with] manufacturing craft creation, but also is applicable to a machine or processes of exportation.For example, a give already set number of thepower each pedestals of I.C. engine have variety.Actually, we usually discover this kind of variety model will be a frequency to distribute curve, for example t.The distributes.(call the Gauss distribute again)One of the work which designs a personnel is the variety which specifies size for a spare parts and allows, this value canproduce acceptable function.
Spare parts business trip
When there is no appointed accurate size in the diagram, most organizations all have in general use business trip of being applicable to the size.For process size, in general use business trip's maying be a ± is 0.5 millimeters.Therefore being specified to 15.0 millimeter scopes of sizes can be of 14.5-15.5 millimeters.Other in general use business trips can be applicable to such as the angle and drill a hole with blunt bore, The casting, the forging, the welded joint and weld the angle）etc. situation.
Can make reference to the diagram of past or general engineering to practice while giving the appointed business trip of a spare parts.The business trip of typical model's ising specified is martial become JSO standard define of range.Give to settle business trip to 1, for example H7/s 6, can use for being studying of spare parts size having 1 set and chart to shoulding of number.Underneath this will give concerning pack into inside bore of the concrete example with the stalk or the pillar form match.
The standard match of bore and stalk
A standard of the engineering work is the business trip which makes sure a pillar form spare parts, installing for example in a tube form spare parts or bore for corresponding of.perhaps is the stalk which revolves in its inner part to match with of loose be decided by application tightly for example, a wheel gear which positions on the stalk
needs to be"tight" of quiet match, here stalk of the diameter compares wheel gear actually of inside path a little bit a little bit big in order to can deliver need of Torque .Furthermore, the diameter of glide bearings has to be big in the diameter of the stalk to make it revolve.On the supposition that speak to can't become the accurate size to the parts manufacturing from the economy, all of the variety of stalk and bore size have to make sure.But, variety of scope shouldn't the too big in order to prevent assemble hour damaged
For being unlikely to there is everlasting drive appointed business trip size endlessly, have already drawn up national and international standard to make sure business trip to take, for example hll/cll.For using this data, gave the definition in the traditional business trip https://www.360docs.net/doc/e19834363.html,ually what to use is the Basic hole system, because this meeting makes company internal auger needed, wring knife and pull knife and calculate the decrease of tool category.
Size:Mean the number of the size numerical value by appropriation unit.
Actual size:The parts size got through a diagraph
Size extreme limit:The spare parts allows of biggest with most baby size.
The biggest size extreme limit:Bigger in two size extreme limits
Most baby size extreme limit:Smaller in two size extreme limits of
Basic size:Fix the reference size of size extreme limit in order to
Deviation:A size with it to should of the algebra of basic size bad
Actual deviation:Actual size with it to should of the algebra of basic size bad.
Last deviation:The biggest size extreme limit with it to should of the algebra of basic size bad
Descend deviation:Most baby size extreme limit with it to should of the algebra of basic size bad
Business trip:The biggest size extreme limit with most the bad value of baby size extreme limit.
Stalk:Specifying an exterior characteristics with all parts consistently uses technical term
Bore:Specify a parts all internal characteristics to consistently use technical term.
The initial design creation satisfies appointed demanding solution.The initial design can represent all sub- systems of constituting the whole system with the total of zero partses.Ion and Smith describe an initial design for is become by a series and evaluate a stage to constitute of an iterative process, each stage matches together to become a good solution.At each iterative stage conceive outline more in detail, can more overall valuation.
Produce possibly many of or the economy is convenient of conceive outline and the viewpoint is important.There is 1 kind to lure, let you accept the first hopeful conceive outline and carry on a detailed design until end product.Should resist this kind of come-on, because of so as a result the head quarter is more quite a few.Well worth mentioning BE, or early or late your design would have to with those designs competitions which come from other manufactories, so the creation develop of the thoughts should be careful.
Is to them to carry on valuation to combine choice next move after producing viewpoint and conceiving outline the best conceive outline.a kind of valuation method is to use row watch matrix.The matrix constitutes to°from a series of standard. conceive outline have to ask for help them to beat a cent.If suitable, the importance of the standard can add power, conceiving outline most in keeping withly will have a tallest total cent.This method provided a built-up valuation technique. and make personal viewpoint that can hardly promote their own absurdity in the team.
Produced the solution of first step, the next move was to express them, in order to they ability and all involve total design process of the persons communicate actually, this one step can adopt forms of drawing the grass diagram or 3D models, since but physical model also but the calculator born model. Of the total plan has been completed and calculated to determine solutions for product design compatibi-
Lity, details of the design phase had been created.
冲压模具技术外文翻译(含外文文献)
前言 在目前激烈的市场竞争中，产品投入市场的迟早往往是成败的关键。模具是高质量、高效率的产品生产工具，模具开发周期占整个产品开发周期的主要部分。因此客户对模具开发周期要求越来越短，不少客户把模具的交货期放在第一位置，然后才是质量和价格。因此，如何在保证质量、控制成本的前提下加工模具是值得认真考虑的问题。模具加工工艺是一项先进的制造工艺，已成为重要发展方向，在航空航天、汽车、机械等各行业得到越来越广泛的应用。模具加工技术，可以提高制造业的综合效益和竞争力。研究和建立模具工艺数据库，为生产企业提供迫切需要的高速切削加工数据，对推广高速切削加工技术具有非常重要的意义。本文的主要目标就是构建一个冲压模具工艺过程，将模具制造企业在实际生产中结合刀具、工件、机床与企业自身的实际情况积累得高速切削加工实例、工艺参数和经验等数据有选择地存储到高速切削数据库中，不但可以节省大量的人力、物力、财力，而且可以指导高速加工生产实践，达到提高加工效率，降低刀具费用，获得更高的经济效益。 1.冲压的概念、特点及应用 冲压是利用安装在冲压设备（主要是压力机）上的模具对材料施加压力，使其产生分离或塑性变形，从而获得所需零件（俗称冲压或冲压件）的一种压力加工方法。冲压通常是在常温下对材料进行冷变形加工，且主要采用板料来加工成所需零件，所以也叫冷冲压或板料冲压。冲压是材料压力加工或塑性加工的主要方法之一，隶属于材料成型工程术。 冲压所使用的模具称为冲压模具，简称冲模。冲模是将材料（金属或非金属）批量加工成所需冲件的专用工具。冲模在冲压中至关重要，没有符合要求的冲模，批量冲压生产就难以进行；没有先进的冲模，先进的冲压工艺就无法实现。冲压工艺与模具、冲压设备和冲压材料构成冲压加工的三要素，只有它们相互结合才能得出冲压件。 与机械加工及塑性加工的其它方法相比，冲压加工无论在技术方面还是经济方面都具有许多独特的优点，主要表现如下； (1) 冲压加工的生产效率高，且操作方便，易于实现机械化与自动化。这是
外文翻译
Load and Ultimate Moment of Prestressed Concrete Action Under Overload-Cracking Load It has been shown that a variation in the external load acting on a prestressed beam results in a change in the location of the pressure line for beams in the elastic range.This is a fundamental principle of prestressed construction.In a normal prestressed beam,this shift in the location of the pressure line continues at a relatively uniform rate,as the external load is increased,to the point where cracks develop in the tension fiber.After the cracking load has been exceeded,the rate of movement in the pressure line decreases as additional load is applied,and a significant increase in the stress in the prestressing tendon and the resultant concrete force begins to take place.This change in the action of the internal moment continues until all movement of the pressure line ceases.The moment caused by loads that are applied thereafter is offset entirely by a corresponding and proportional change in the internal forces,just as in reinforced-concrete construction.This fact,that the load in the elastic range and the plastic range is carried by actions that are fundamentally different,is very significant and renders strength computations essential for all designs in order to ensure that adequate safety factors exist.This is true even though the stresses in the elastic range may conform to a recognized elastic design criterion. It should be noted that the load deflection curve is close to a straight line up to the cracking load and that the curve becomes progressively more curved as the load is increased above the cracking load.The curvature of the load-deflection curve for loads over the cracking load is due to the change in the basic internal resisting moment action that counteracts the applied loads,as described above,as well as to plastic strains that begin to take place in the steel and the concrete when stressed to high levels. In some structures it may be essential that the flexural members remain crack free even under significant overloads.This may be due to the structures’being exposed to exceptionally corrosive atmospheres during their useful life.In designing prestressed members to be used in special structures of this type,it may be necessary to compute the load that causes cracking of the tensile flange,in order to ensure that adequate safety against cracking is provided by the design.The computation of the moment that will cause cracking is also necessary to ensure compliance with some design criteria. Many tests have demonstrated that the load-deflection curves of prestressed beams are approximately linear up to and slightly in excess of the load that causes the first cracks in the tensile flange.(The linearity is a function of the rate at which the load is applied.)For this reason,normal elastic-design relationships can be used in computing the cracking load by simply determining the load that results in a net tensile stress in the tensile flange(prestress minus the effects of the applied loads)that is equal to the tensile strength of the concrete.It is customary to assume that the flexural tensile strength of the concrete is equal to the modulus of rupture of the
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）
5外文翻译原文1
A Case Study of Pattern-based Software Framework to Improve the Quality of Software Development Chih-Hung Chang, Chih-Wei Lu Dept. of Information Management, Hsiuping Institute of Technology No.11, Gongye Rd., Dali City, Taichung County, Taiwan(R.O.C.) 886-4-24961123 ext 3112 {chchang,cwlu}@ https://www.360docs.net/doc/e19834363.html,.tw William C. Chu Dept. of Computer Science and Information Engineering, Tunghai University No.181, Sec. 3, Taichung Port Rd.,Taichung City, Taiwan (R.O.C.) 886-4-23508983 cchu@https://www.360docs.net/doc/e19834363.html,.tw Nien-Lin Hsueh Dept. of Information Engineering and Computer Science, Feng Chia University No. 100 Wenhwa Rd., Taichung, Taiwan (R.O.C.) 886-4- 24517250 ext 3773 nlhsueh@https://www.360docs.net/doc/e19834363.html,.tw Chorng-Shiuh Koong Dept. of Computer and Information Science, Taichung University No.140, Ming-Sheng Rd., Taichung City, Taiwan (R.O.C.) 886-4-22183804 csko@https://www.360docs.net/doc/e19834363.html,.tw ABSTRACT In recent years, development of the software industry and demand for software systems have increased rapidly, but developers often does not know whose suggestion to follow regarding methodologies of software engineering. One reason for that is the difficulty in applying new software engineering technologies. Developers take a long time to train. Another reason is the difficulty in integrating CASE toolsets. So many indeterminate factors make the development process more and more complex. On the other hand, software development is too customized, and software reuse is difficult. T he reasons above are the cause for software development and maintenance to become more complex and difficult to control. In this paper we explore the importation of a software pattern-based framework, and the development of an ERP/support chain system. Based on software patterns, developers can separate development and business so as to reduce problems caused by the developer’s lack of business experience. T he quality of the product can thus be enhanced, software development costs be reduced, and software maintenance be improved. Keywords Design Pattern, Framework, Software Development Process, XML 1.INTRODUCTION In Object-Oriented T echnology, the property of inheritance allows software components to be reused, which can obviously reduce the cost of software development. For this reason, to produce a highly reusable software component is an important goal of software engineering. However, programmers are usually focused on code reuse while ignoring design reuse. Design patterns provide a clear concept of design structure by describing the relationships of inheritance and reference between components of the system. Design patterns are a series of familiar usages and constructions utilized throughout system design. Design patterns allow rapid coding of certain components by following certain patterns of steps. T his can improve the documentation and maintenance of existing systems by providing an explicit specification of class, object interactions and their underlying intents. One of the main purposes of design patterns is to help software engineers to understand the common characteristics of software objects/components in specialized domain. In recent years, due to the development and maturation of WWW and Java [14] technologies, many applications are now web applications or leaning in that direction. Many software concepts are utilized for the web as well, such as Design Patterns and Frameworks. The Apache Struts [12] and Spring Framework [13] are both open source frameworks used to address and reduce the complexity of developing an enterprise application. T he advantage of using a framework is the layered architecture it provides. Layered architecture allowed users to choose the component desired, while also providing the integration framework when developing application using J2EE. T hese developing web concepts can facilitate the development of web applications. However, these very useful tools and concepts lack a systematic organization. We hope to use these open source software technologies to develop a software framework which can be applied to web application. T his should solve the problem of web applications lacking a good structure, while through applying these open source software technologies, software development costs will be reduced. Furthermore, a guideline for programmers who wants to use these open source technologies will be provided. This paper is organized as follows: In the next section, we discuss works related to our project; in section 3, the open source technologies used in the paper and the system implementation will be described; Section 4 is a sample experiment. T he conclusion is given in section 5.
机械设计外文翻译(中英文)
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。
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。
外文翻译五分钟搞定5000字
五分钟搞定5000字－外文文献翻译，你想要的工具都在这里。【大四的时候写毕业论文老师就要求得翻译外文文献并写入论文】来源：董绪的日志 五分钟搞定5000字－外文文献翻译 工具大全https://www.360docs.net/doc/e19834363.html,/node/2151 建议收藏 在科研过程中阅读翻译外文文献是一个非常重要的环节，许多领域高水平的文献都是外文文献，借鉴一些外文文献翻译的经验是非常必要的。由于特殊原因我翻译外文文献的机会比较多，慢慢地就发现了外文文献翻译过程中的三大利器：G oogle“翻译”频道、金山词霸（完整版本）和CNKI“翻译助手"。 具体操作过程如下： 1.先打开金山词霸自动取词功能，然后阅读文献； 2.遇到无法理解的长句时，可以交给Google处理，处理后的结果猛一看，不堪入目，可是经过大脑的再处理后句子的意思基本就明了了； 3.如果通过Google仍然无法理解，感觉就是不同，那肯定是对其中某个“常用单词”理解有误，因为某些单词看似很简单，但是在文献中有特殊的意思，这时就可以通过CNKI的“翻译助手”来查询相关单词的意思，由于CNKI的单词意思都是来源与大量的文献，所以它的吻合率很高。 另外，在翻译过程中最好以“段落”或者“长句”作为翻译的基本单位，这样才不会造成“只见树木，不见森林”的误导。 注： 1、Google翻译：https://www.360docs.net/doc/e19834363.html,/language_tools google，众所周知，谷歌里面的英文文献和资料还算是比较详实的。我利用它是这样的。一方面可以用它查询英文论文，当然这方面的帖子很多，大家可以搜
索，在此不赘述。回到我自己说的翻译上来。下面给大家举个例子来说明如何用吧 比如说“电磁感应透明效应”这个词汇你不知道他怎么翻译， 首先你可以在CNKI里查中文的，根据它们的关键词中英文对照来做，一般比较准确。 在此主要是说在google里怎么知道这个翻译意思。大家应该都有词典吧，按中国人的办法，把一个一个词分着查出来，敲到google里，你的这种翻译一般不太准，当然你需要验证是否准确了，这下看着吧，把你的那支离破碎的翻译在g oogle里搜索，你能看到许多相关的文献或资料，大家都不是笨蛋，看看，也就能找到最精确的翻译了，纯西式的！我就是这么用的。 2、CNKI翻译：https://www.360docs.net/doc/e19834363.html, CNKI翻译助手，这个网站不需要介绍太多，可能有些人也知道的。主要说说它的有点，你进去看看就能发现：搜索的肯定是专业词汇，而且它翻译结果下面有文章与之对应（因为它是CNKI检索提供的，它的翻译是从文献里抽出来的），很实用的一个网站。估计别的写文章的人不是傻子吧，它们的东西我们可以直接拿来用，当然省事了。网址告诉大家，有兴趣的进去看看，你们就会发现其乐无穷！还是很值得用的。https://www.360docs.net/doc/e19834363.html, 3、网路版金山词霸（不到1M）：https://www.360docs.net/doc/e19834363.html,/694690163794 4806 翻译时的速度： 这里我谈的是电子版和打印版的翻译速度，按个人翻译速度看，打印版的快些，因为看电子版本一是费眼睛，二是如果我们用电脑，可能还经常时不时玩点游戏，
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