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 时间:2018-06-27  贡献者:筑魂路

导读:土木工程专业英语第二版课文翻译_土木工程专业英语,Lesson 1 Machinery design may be simple or enormously complex, easy or difficult, mathematical or nonmathematical, it may involve a trivial problem or one of great importance. 机械设计可能简单,可能复杂;可能容易,可能

土木工程专业英语第二版课文翻译_土木工程专业英语
土木工程专业英语第二版课文翻译_土木工程专业英语

Lesson 1 Machinery design may be simple or enormously complex, easy or difficult, mathematical or nonmathematical, it may involve a trivial problem or one of great importance. 机械设计可能简单,可能复杂;可能容易,可能困难;可能要求精确,也可能不精确;有 时要解决的可能是一些很平常琐碎的问题,也可能是非常重大的问题。

In the modern industrialized world, the wealth and living standards of a nation are closely linked with their capabilities to design and manufacture engineering products. It can be claimed that the advancement of machinery design and manufacturing can remarkably promote the overall level of a country’s industrialization. 在现代的工业化社会,一个国家的财富和生活水平与他们设计和制造工程产品的能力紧密 相关,可以说机械设计和制造业的进步能显著地促进一个国家工业化整体水平的提高。

Definition of problem is necessary to fully define and understand the problem, after which it is possible to restate the goal in a more reasonable and realistic way than the original problem statement. 定义问题对全面认识、理解问题非常必要,之后可以更加合理可行的方式来重新阐述。

The synthesis is one in which as many alternative possible design approaches are sought, usually without regard for their value or quality. 综合就是对各种可供选择的设计方法进行进一步研究,这时往往不考虑这些方法的设计特 点和设计质量。

This is also sometimes called the ideation and invention step in which the largest possible number of creative solutions is generated. 这有时也称为构思和发明阶段,在这个阶段中要产生尽可能多的有创意的想法。

The competent engineer should not be afraid of the possibility of not succeeding in a presentation 有能力的工程师不应该害怕在提高自己的方案时遭遇失败。

In fact, the greatest gains are obtained by those willing to risk defeat. 实际上,失败乃成功之母。

there is strong sense of satisfaction and pride inseeing the results of one's ceartive efforts emerge into actual products and processes that benefit people. 当看到自己创造性的努力成果转变成可以造福人们的实际产品和工作流程时,一种强烈的 满足感和骄傲感油然而生。

the design engineer should not only have adequate technical training,but must also be a person of sound judgment and wide experence,qulities which are usually acquired only after considerable time has been spent in actual proessional work. 设计师不仅需要足够的技术训练,而且还必须是一个具备合理的判断和丰富经验的人,具 备这些素质通常需要在实际工作中花费相当长的时间。

Lesson 2 mechanisms 1、a mechanism is the members combination more than two or two connections with the members to realize the regulation motion made by way of the activity. 机构是由两个或两个以上的构件通过活动联接以实现规定运动的

构件组合,是机械的组成部分。

2、 Activity connections between two members that have the relative motion are called the motion pairs . 两个有相对运动的构件间的活动连接称为运动副。

3、All motion pairs contact with planes are called lower pairs and all motion pairs contact with points or lines are called high pairs .其中凡为面接触的运动 副称为低副凡为点或线接触的运动副成为高副。

4 、 The motion specific property of mechanism chiefly depends on the relative size between the members, and the character of motion pairs, as well as the mutual disposition method etc.机构的运动特性主要取决于构件间的相对尺寸、 运动副的性质以及相互配置方式等。

5、The member is used to support the members of motion in the mechanism to be called the machine frame and used as the reference coordinate to study the motion system. 机构中用以支持运动构件的构件称为机架,并被当做研究运动的参考坐标系。

6、The member that possesses the independence motion is called motivity member. The member except machine frame and motivity member being compelled to move in the mechanism is called driven member.具有独立运动的构件称为原动件。

机构中除 机架和主动件之外的被迫做强制运动的构件称为从动件。

7、The independent parameter (coordinate number) essential for description or definite mechanism motion is called the free degree of mechanism.描述或确定机构 的运动所必需的独立参变量(坐标数)称为机构自由度。

8、For gaining the definite relative motion between the members of mechanism, it is necessary make the number of motivity members of mechanism equal the number of free degrees.为使机构的构件获得确定的相对运动,必需使机构的原动件数等 于机构自由度数。

9、Mechanisms may be categorized in several different ways to emphasize their similarities and differences.根据各个不同机构之间的异同点,常采用以下几种不同的 分类方法。

10、A planar mechanism is one in which all particles describe plane curves in space and all these curves lie in parallel planes;i.e. the loci of all points are plane curves parallel to a single common plane.在平面机构中,所有的点在空间 绘出的是平面曲线,且所有的点的轨迹是与一个单一公共平面相平行的平面曲线。

11、The plane four-bar linkage, the plate cam and driven parts, and the slidercrank mechanism are familiar examples of planar mechanism.平面四连杆机构、平面 盘形凸轮、从动件及曲柄滑块机构等都是平面机构的常见例子。

12 、 As such, cams are widely used in almost all machinery. They include internal combustion engines, a variety of machine tools, compressors and computers.这样便使凸轮广泛用于几乎所有的机械设备中,包括内燃机、各种机床、压缩 机和计算机。

2.4 Exercise Translate the lineate phrases and fill in the brackets 该机构为平面四连杆机构( the plane four-bar linkage), 1 为机架(machine frame), 2 为原动件(motivity member), 3、4 为从动件( driven member), A 为回转副( revolute pairs),属于低副(lower pairs),

B 为固定连接( fixed connection)。

构件( component )4 中的焊接符号(welding symbol )表示 4 为一个构件。

该机构的自由度数( the number of free degree)必须等于原动件数,才能实现确定的 运动(motion)。

Unit4 1:Fasteners are devices which permit one part to be joined to a second part and, hence, they are involved in almost all designs. 紧固件可以将一个零件与另一个 零 件相 连接。

因此 ,几乎 在所 有 的设 计中 都要用 到紧 固件。

There are three main classifications of fasteners, which are described as follows. 紧固件可以分为以 下 3 类。

2 : The failure or loosening of a single fastener could result in a simple nuisance such as a door rattle or in a serious situation such as a wheel coming off. Such possibilities must be taken into account in the selection of the type of fastener for the specific application. 一个紧固件的失效或松动肯能会带来车门 嘎嘎响这类小麻烦,也可能造成车轮脱落这种严重后果。

因此,在为一个特定用途选择紧 固件时,应该考虑到上述各种可能性。

3:Nuts, bolts, and screws are undoubtedly the most common means of joining materials. Since they are so widely used, it is essential that these fasteners attain maximum effectiveness at the lowest possible cost. 由于紧固件应用非常广 泛,所以对它们来说,价格低,功效高是非常必要的。

4:The lock washer is useful only when the bolt might loosen because of a relative change between the length of the bolt and the parts assembled by it. 锁紧垫圈仅在螺栓与装配件间长度相对 变化而松动时才起作用。

5 : This change in the length of the bolt can be caused by a number of factors-creep in the bolt, loss of resilience, difference in thermal expansion between the bolt and the bolted members, or wear. 这种螺 栓长度的变化可由多种因素引起-螺栓内部蠕变、弹性丧失、螺栓与被连接件间的热膨胀差 异或磨损。

6 : Shafts are mounted in bearings and transmit power through such devices as gears, pulleys, cams and clutches. 轴安装在轴承中,通过齿轮、皮带轮、凸轮和离 合器等传递动力。

7:These devices introduce forces which attempt to bend the shaft; hence, the shaft must be rigid enough to prevent overloading of the supporting bearings. 通过这些零件传递的力可能会使轴发生弯曲变形,因此,轴应该有足够的刚度以防止支承 轴承受力过大。

8 : Another important aspect of shaft design is the method of directly connecting one shaft to another. This is accomplished by devices such as rigid and flexible couplings. 在轴的设计中,轴与轴之间的连接方法是要重点考虑的,可 由刚性或者弹性联轴器来实现。

9 : However, in the case of bearings, the reduction of friction is one of the prime considerations: Friction results in loss of power, the generation of heat, and increased wear of mating surfaces. 然而,设计轴承时,减小摩擦是要考虑的基本因素之一,因为摩擦会导致功率下降、发热 和 配 合 表 面 的 磨 损 。

10 : The deflection of the bearing elements will become important where loads are high, although this is usually of less magnitude than that of the shafts or other components associated with the bearing. 当载荷较大 时,轴承零件会发生变形,尽管变形的程度远小于轴或其它与轴承相连的零部件,但仍然

会有很大的影响。

11 : Wear is primarily associated with the introduction of contaminants, and sealing arrangements must be chosen with regard to the hostility of the environment. 磨损主要由污染物的进入引起,必须选用密封装置以防止周围环境的不良 影响。

12:Notwithstanding the fact that responsibility for the basic design of ball bearings and roller bearings rests with the bearing manufacturer, the machine designer must form a correct appreciation of the duty to be performed by the bearing and be concerned not only with bearing selection but with the conditions for correct installation. 尽管球轴承和滚子轴承的设计由轴承制造厂负 责,但是,机器设计人员必须对轴承的使用有一个正确估计,不仅要考虑轴承的选择,而 却还要考虑轴承的正确安装条件。

13 : A bearing is a connector that permits the connected members to either rotate or translate(more to and from) relative to one another but prevents them from separating in the direction in which loads are applied. 轴承是一个连接 器,它不仅允许连接件旋转或相互传递力,而却可以防止它们在负载的方向上分开。

14:Sliding bearing are the simplest to construct and, considering the multitude of pin-jointed devices and structures in use,are probably the most commonly used. 滑动轴承是最简单的构件,考虑到大量的销接设备和结构都在使用,所以滑动轴承是最常 使用的。

第六章 1 、 Computer – aided design CAD is defined as the application of computers and graphics software to aid or enhance the product design from conceptualization to documentation. 计算机辅助设计(CAD)就是在产品设计过程中,利用计算机和图形软件,对产品进行辅助 设计以提高产品设计效率的一种技术。

2、The major advantage of a 2-D model is that it gives a certain amount of 3-D information about a part without the need to create the database of a full 3-D model. 二维半模型则可以表示出零件单侧连续截面的形状细节,它的主要优点在于不需要建立完 整的三维模型就可以表达出零部件必要的形状特点。

3 、 FEM analysis is available on most CAD systems to aid in heat transfer, stress-strain analysis, dynamic characteristics, and other engineering computations. 在大多数 CAD 系统中可以进行有限元分析,主要分析内容包括对零部件进行传热状况分 析、应力——应变分析、动力学特性分析等。

4 、 CAM can be defined as computer aided preparation manufacturing including decision-making, process and operational planning, software design techniques, and artificial intelligence, and manufacturing with different types of automation (NC machine, NC machine centers, NC machining cells, NC flexible manufacturing systems), and different types of realization (CNC single unit technology, DNC group technology). CAM 定义为计算机辅助制造,它包括制造决策、生产过程和操作规划、程序设计、人工智 能、自动化控制制造设备(如数控机床、数控加工中心、数控加工单元、数控柔性制造系 统)及相应的技术(如数控单元技术,直接数控成组技术) 。

5 、 When a design has frozen, manufacturing can begin. Computers have an important role to play in many aspects of production. 产品设计好之后,接下来就是对其进行制造。

如今在机械产品制造中的许多环节里,计算 机都扮演着重要的角色。

6、Computer aided process planning (CAPP) can be defined as the functions which use computers to assist the work of process planners.The levels of assistance depend on the different strategies employed to implement the system. 计算机辅助工艺设计(CAPP)就是工艺员借助计算机制定产品工艺流程的过程,利用的程 度取决于制定流程的方法。

Lower level strategies only use computer for sotrage and retrieval of the data for the process plans which will be constructed manually by process planners,as well as for supplying the data which will be used in the planner’s new work. 低层次的辅助工艺员设计是指工艺员利用计算机对手工完成的工艺数据进行存储和修改, 同时为编制新的工艺流程提供数据。

7 、 The highest level strategy,which is the ultimate goal of CAPP,generates process plans by computer,which may replace process planners,when the knowledge and experties of process planning and working experience have been incorporated into the computer programs. 最高层次的计算机辅助工艺设计也是 CAPP 的最终实现目标,它将工艺流程编制的理论、技 术以及经验编成程序输入计算机,由计算机自动完成工艺流程的编制,不需要工艺员的参 与。

8 、 The database in a CAPP system based on the highest level strategy will be directly integrated with conjunctive systems,e.g.CAD and CAM.CAPP has been recognized as playing a key role in CIMS (Computer integrated manufacturing system). 此外,它的数据库可直接与其他系统集成,如 CAD 系统和 CAM 系统,因此,CAPP 被认为是 计算机集成制造系统中的一个重要组成部分。

7 单元 1 、 Generally, an optimization method controls a series of applications, including CAD software as well as FEA automatic solid meshers and analysis processors. 优化方法决定了产品设计过程中的京都问题,包括 CAD 软件建模的精确度,有限元分析中 网格划分的正确度以及分析处理器的计算精度等。

Ideally, there is seamless data exchange via direct memory transfer between the CAD and FEA applications without the need for file translation. 从优化设计理论的角度上说,CAD 格式的文件和 FEA 格式的文件之间不需要任何的格式转 换,就可以实现数据的无缝交换。

2 、 The user simply selects which dimension in the CAD model needs to be optimized and the design criterion, which may include maximum stresses, temperatures or frequencies. The analysis process appropriate for the design criteria is then performed. 用户只要挑选出零件部件或装配体 CAD 模型中需要优化的几何尺寸,确定相应的设计准则 (如最大应力、最高温度和最大频率) 。

3、Care is taken such that the FEA model is also updated using the principle of associativity, which implies that constraints and loads are preserved from the