章跃机械制造工程专业英语---Lesson 1 Mechanical Properties of Metals
机械工程专业英语(1)
二. 句子结构特点
1. 句子长 2. 被动语态多 e.g: The rate at which work is done is called power. 3. 后置定语多 4. 名词化结构多 e.g: to control the machine ---- the control of the machine
学习方法与教学方法 工具书的介绍
1. 收词不足,收词量有限 2. 收词面广 3. 例证丰富 4. 释义地道, 全面 5. 词的用法说明较详细
Lesson 1 Introduction for Materials
Designers and engineers are usually more interested in the behavior of materials under load or when in a magnetic field than in why they behave as they do.
In this case structure-insensitive properties include the traditional physical properties: electrical and thermal conductivity, specific heat, density, and magnetic and optical properties.
1. the measured magnitude: 测定的大小 2. response to: 对…..的反应
In engineering materials the properties are recorded in handbooks or, for new materials, are made available by the supplier.
(完整版)1机械工程专业英语第一课-1
机械工程专业英语第一课机械工程专业英语概述English in Mechanical Engineering一、专业英语概述1. 什么是翻译：翻译就是将一种语言文字的意义用另一种语言文字表达出来。
机械工程英语翻译就是将机械工程学科的英语原著由原作语言(source language)用译文语言(target language)忠实、准确、严谨、通顺、完整地再现出来，使人们能够借助汉语译文准确无误地了解英语机械工程著作所阐述的工程技术内容和科学理论。
机械工程专业英语概述English in Mechanical Engineering2. 翻译例句例1. Control Center, Smoking Free.例2. The tolerance should not be so big.例3. A dog driver stop the rotation of the wheel. 例4. Connect the black pigtail with thedog-house.例5. The importance of computer in the use of manufacturing can not be overestimated. 机械工程专业英语概述English in Mechanical Engineering例1. Control Center, Smoking Free.错误译法：控制中心，吸烟自由。
正确译法：控制中心，严禁吸烟。
例2. The tolerance should not be so big.a. 此公差不应给这么大。
（机械学）b. 忍耐力不会有这么大。
(关于人体的耐受性)c. 抗毒性不会有这么强。
（医学）例3. A dog driver stop the rotation of the wheel. 错误译法：狗驾驶员使轮子停转。
专业译法：止动器使轮子停止旋转。
机械设计制造及其自动化专业英语UnitMechanicalPropertiesofMaterialsPPT课件
精品课件 10
Mechanical properties
• This is depicted [diˈpekt] by the straight line relationship and a small deviation [ˌdiviˈeʃən] thereafter, in the stress-strain curve (Fig. 3. 1).
• 而在这其中最重要的是腐蚀性，通俗的解释 是材料在特定大气中长期使用时，抵抗腐(败) 蚀的能力。
精品课件 5
Mechanical properties
• Mechanical properties include the strength properties like tensile, compression, shear, torsion, impact, fatigue and creep .
word
• cross-section 横截面 • ordinate n. 纵坐标 [ˈɔ:rdineit] • abscissa n. 横坐标 [əbˈsisə] • deviation n. 偏离；偏移 [ˌdi:viˈeiʃən] • time-lag 延时；落后；时滞 • yield n. ； v. 屈服 [ji:ld] • elongation n. 延伸率；伸长 [ˌi:lɔŋ'ɡeiʃən] • diminish n. 减小；缩小 [diˈminiʃ] • necking n. 颈缩；形成细颈现象 ['nekiŋ]
• 材料在加载时，随着载荷大小的变化，尺寸 会发生改变。
精品课件 9
Mechanical properties
机械专业英语(章跃版)课后英汉翻译讲解
第一章：应力与应变1.That branch of scientific analysis which motions, times and forces is called mechanics and is made up of two parts, statics and dynamics.研究位移、时间和力运动乘力是科学分析法的一个分歧，被称作力学，力学由两大部分组成，静力学和动力学。
2.For example, if the force operating on a sleeve bearing becomes too high, it will squeeze out the oil film and cause metal-to-metal contact, overheating and rapid failure of the bearing.例如：如果止推轴承上的作用力过大的话，会挤出油膜，引起金属和金属之间的相互接触，轴承将过热而迅速失效。
3.Our intuitive concept of force includes such ideas as place of application, direction, and magnitude, and these are called the characteristics of a force.力的直观概念包括力的作用点、大小、方向，这些被称为力的三要素。
4.All bodies are either elastic or plastic and will be deformed if acted upon by forces. When the deformation of such bodies is small, they are frequently assumed to be rigid, i.e., incapable of deformation, in order to simplify the analysis.所有的物体既可以是弹性的也可以是塑性的，如果受到力的作用就产生变形。
机械工程专业英语 第一课文及阅读材料
Lesson1 the mechanical design process 1, the mechanical design processThe ultimate objective of mechanical design is to produce a useful product that satisfies the needs of a customer and that is safe ,efficient, reliable, economical, and practical to manufacture .think broadly when answering the question ,”who is the customer for the product or system I am about to design?”it is essential that you know the desires and expectations of all customers before product design. marketing professionals are often employed to manage the definition of customer expectations , but designers will likely work with them as a part of a product development team .many methods are used to determine what the customer wants. One popular method , called quality function deployment or QFD , seeks(1) to identify all of the features and performance factors that customers desire and (2) to assess the relative importance of these factors. the result of the QFD process is a detailed set of functions and design requirements for the product.It is also important to consider how the design process fits with all functions that must happen to deliver a satisfactory product to the customer and to service the product throughout its lift cycle. in fact, it is important to consider how the product will be disposed of after it hasserved its useful life . the total of all such function that affect the product is sometimes called the product realization process or PRP . some of the factors included in PRP are as follows:1 marketing functions to assess customer requirements2 research to determine the available technology that can reasonably be used in the product3 availability of materials and components that can be incorporated into the product4 product design and development5 performance testing6 documentation of the design7 vendor relationships and purchasing functions8 work-force skills9 physical plant and facilities available10 capability of manufacturing systems11production planning and control of production systems12production support systems and personnel13 quality systems requirements14 sales operations and time schedules15 cost targets and other competitive issues16 customer service requirements17 environmental concerns during manufacture , operation anddisposal of the product18 legal requirements19 availability of financial capitalCan you add to this list? You should be able to see that the design of a product is but one part of a comprehensive process. in this text, we will focus more carefully on the design process itself , but the producibility of designs must always be considered . this simultaneous consideration of product design and manufacturing process design is often called concurrent engineering.2 skills needed in mechanical designProduct engineers and mechanical designers use a wide range of skills and knowledge in their daily work . these skills and knowledge are included in the following :1sketching, technical drawing , and computer-aided design2 properties of materials, materials processing, and manufacturing processes3 applications of chemistry, such as corrosion protection, plating , and painting4 statics, dynamics, strength of materials , kinematics, and mechanisms5 fluid mechanics, thermodynamics, and heat transfer6 fluid power, the fundamentals of electrical phenomena, andindustrial controls7 experimental design and performance testing of materials and mechanical systems8 stress analysis9 specialized knowledge of the behavior of machine elements, such as gears, belt drives, chain drives, shafts, bearings, keys, splines, couplings, seals, spring, connections(bolted, riveted, welded, adhesive), electric motors, linear motion devices, clutches, and brakes10 creativity , problem solving ,and project management11 oral communication, listening, technical writing, and teamwork skills3 functions , design requirements and evaluation criteriaSection 1 emphasized the importance of carefully identifying the needs and expectations of the customer prior to beginning the design of a mechanical device. you can formulate these by producing clear , complete statements of functions, design requirements , and evaluation criteria:1 Functions tell us what the device must do , using general , nonquantitative statements that employ action phrases such as “to support a load”, “to lift a crate ”, “to transmit power”, or “to hold two structural members together”, etc2 Design requirements are detailed, usually quantitativestatements of expected performance levels, environmental conditions in which the device must operate, limitations on space or weight , or available materials and components that may be used3 Evaluation criteria are statements of desirable qualitative characteristics of a design that assist the designer in deciding which alternative design is optimum-that is , the design that maximizes benefits while minimizing disadvantagesTogether these elements can be called the specifications for the designMost designs progress through a cycle of activities are outlined in figure1.1. you should typically propose more than one possible alternative design concept. This is where creativity is exercised to produce truly novel designs .Each design concept must satisfy the functions and design requirements . a critical evaluation of the desirable features, advantages, and disadvantages of each design concept should be completed . then a rational decision analysis technique should use the evaluation criteria to decide which design concept is the optimum and , therefore , should be produced.Reading materialMechanical design is the process of designing and/or selecting mechanical components and putting them together to accomplish a desired function. Of course machine elements must be compatible ,must fit well together , and must perform safely and efficiently. The designer must consider not only the performance of the element being designed at a given time , but also the elements with which it must interface.To illustrate how the design of machine elements must be integrated with a larger mechanical design , let us consider the design of a speed reducer for the small tractor . suppose that,to accomplish the speed reduction ,you decide to design a double-reduction, spur gear speed reducer. You specify four gears , three shafts , six bearings, and a housing to hold the individual elements in proper relation to each other. The primary elements of the speed reducer are :1 the input shaft is to be connected to the power source, a gasoline engine whose output shaft rotates at 2000 rpm . a flexible coupling is to be employed to minimize difficulties with alignment .2 the first pair of gears, a and b ,causes a reduction in the speed of the intermediate shaft proportional to the ratio of the numbers of teeth in the gears. Gear b and c are both mounted to intermediate shaft and rotate at the same speed .3 a key is used at the interface between the hub of each gear and the shaft on which it is mounted to transmit torque between the gear and the shaft .4 the second pair of gears , c and d ,further reduces the speed of gear d and the output shaft to the range of 290 rpm to 295 rpm .5 the output shaft is to carry a chain sprocket.the chain drive ultimately is to be connected to the drive wheel of the tractor.6 each of the three shafts is supported by two ball bearings .making them statically determinate and allowing the analysis of forces and stresses using standard principles of mechanics.7 the bearings are held in a housing that is to be attached to the frame of the tractor . note the manner of holding each bearing so that the inner race rotates with the shaft while the outer race is held stationary.8 seals are on the input and output shafts to prohibit contaminants from entering the housing .9 details of how the active elements are to be installed , lubricated, and aligned are only suggested at this stage of the design process to demonstrate feasibility .one possible assembly process could be as follows.Start by placing the gearing the gears, keys, spacers, and bearings on their respective shaftsThen insert input shaft into its bearing seat on the left side of the housing.Insert the left end of intermediate shaft into its bearing seat whileengaging the teeth of gears a and b.Install the center bearing support to provide support for the bearing at the right side of input shaft.Install output shaft by placing its left bearing into the seat on the center bearing support while engaging gears c and d.Install the right side cover for the housing while placing the final two bearings in their seats.Ensure careful alignment of the shafts.Place gear lubricant in the lower part of housing .The arrangement of the gears, the placement of the bearings so that they straddle the gears , and the general configuration of the housing are also design decisions . the design process cannot rationally proceed until these kinds of decisions are made . when the overall design is conceptualized, the design of the individual machine elements in the speed reducer can proceed . you should recognize that you have already made many design decisions by rendering such a sketch . first, you choose spur gears rather than helical gears , a worm and worm gear , or bevel gears. in fact , other types of speed reduction devices –belt drives , chain drives, or many others—could be appreciate.1gearsfor the gear pairs ,you must specify the number of teeth in each gear ,the pitch (size) of the teeth , the pitch diameters, the face width ,and the material and its heat treatment . these specifications depend on considerations of strength and wear of the gear teeth and the motion requirements(kinematics ). You must also recognize that the gears must be mounted on shafts in a manner that ensures proper location of the gears, adequate torque transmitting capability from the gears to the shafts (as through keys ) and safe shaft design.2shaftshaving designed the gear pairs, next you will consider the shaft design . the shaft is loaded in bending and torsion because of the forces acting at the gear teeth . thus, its design must consider strength and rigidity , and it must permit the mounting of the gears and bearings . shafts of varying diameters may be used to provide shoulders against which to seat the gears and bearings. There may be keyseats cut into the shaft, the input and output shafts will extend beyond the housing to permit coupling with the engine and the drive axle . the type of coupling must be considered, as it can have a dramatic effect on the shaft stress analysis. Seals on the input and output shafts protect internal components.3bearingsdesign of the bearings is next. If rolling contact bearings are to be used , you will probably select commercially available bearings from a manufacturer’s catalog , rather than design a unique one . you mustfirst determine the magnitude of the loads on each bearing from the shaft analysis and the gear designs. The rotational speed and reasonable design life of the bearings and their compatibility with the shaft on which they are to be mounted must also be considered. For example , on the basis of the shaft analysis, you could specify the minimum allowable diameter at each bearing seat location to ensure safe stress levels . the bearing selected to support a particular part of the shaft ,then , must have a bore( inside diameter) no smaller than necessary. When a specific bearing is selected , the shaft at the bearing seat location and allowable tolerances must be specified ,according to the bearing manufacturer’s recommendations , to achieve proper operation and life expectancy of the bearing.。
机械制造专业英语4B原文及翻译(章跃主编)
CHAIN DRIVESChain drives occupy a unique position in the mechanical field.In a sense,they are similar to belt drives;a chain connects sprockets on the driving and driven shafts.The velocity ratio transmitted from one shaft to the other depends on the size of the two sprockets(at the pitch line);unlike that found with belts,the ratio is positive.In belt drive ,creep and slip play important roles and must be considered;in a chain drive,which is made up of numerous links,there is a small amount of play in the total length of the chain.This may be desirable in case of small overloads.A chain drive is similar to the open-belt type of dirve in that the driving and driven shafts rotate in the same direction.There are also similarities between chain drives and gear drives.Both types transmit a positive velocity ratio.In a regular spur-gear drive,the driving and driven shafts turn in opposite directions unless an idler is employed.In gear drives employing an annular or ring gear,however,the input and output shafts rotate in the same direction.In a spur-gear drive there is very little contact between meshing gears;therefore,tooth loads are excessive.Since the connection between a chain and its sprocket extends over several teeth,no one tooth is subjected to heavy loads.Chain drives are often noisy.The silent chain type of drive was developed to counteract this undesirable characteristic.Belt,chain,and gear drives are all dangerous.Belt and chain speeds are high,as is the pitch-line velocity of most gear drives.All should be adequately covered by suitable guards(or completely enclosed) so that no boby or clothing parts can possibly be caught in the moving components.Other comparisons can be made among chain,belt,and gear drives.Gear drives can operate at higher speeds than the others,and are usually more compact.However,chain drives do not require the mounting precision that is so essential for gearing.An advantage of chain drives in comparison to belt drives is that the former do not require tension on the slack side;this leads to better bearing life.In general,chain drives are more compact than the belt type;for a given ratio,the sprockets can be smaller than belt pulleys.For a given load,chain widths are narrower than comparable flat belts.The connecting link on chain drives makes them easy to install—the chain is merely placed over the sprockets and the proper pins are placed in position.In most belt installations,force is needed to place the belt in the proper position;such action is detrimental to mounting bearings.The angle of contact for the driving sprocket can be smaller than the driving pulley for a belt drive.For a chain drive,this angle can be as small as 120 degrees.The center distance can also be small;if a 120-degree angle of contact is provided,the center distance need be no more than just enough to provide clearance for the sprocket teeth.An essential part of any chain drive is the sprocket.A chain drive requires a sprocket on the driving shaft and another on the driven shaft.Chain drives sometimes contain additional sprockets,used for additional power take-offs or for taking up chain slack.When used to take up chain slack,they are known as idlers.Idlers should be mounted on the slack side,not on the tight side.It is desirable to have an adjustment for idler positioning where possible.Fig.4-5 showsa roller-chain sprocket.Sprocket teeth are standardized to accommodate the roller chain.Various sizes of sprockets may be used,and several types are available.The simplest type is one without a hub.Sprockets are also available with hubs on one side or on both sides.Special arrangements are also possible.Certain of these are used in conjunction with a shear-pin hub;the shear pin is designed to fail in case of an accidental or unexpected overload.Some types can be installed on large lineshafts;these sprockets are made in two parts so that they can be installed without disconnecting the long length of shafting.Smaller sprockets are usually made solid;large ones are sometimes constructed with arms or spokes to reduce weight.In general,the selection of a sprocket depends on the type of application.链传动链传动在机械领域中占据了独特的地位。
章跃机械制造工程专业英语---Lesson 2 Hardening and Tempering
Lesson 2 Hardening and TemperingPlain carbon steel has been valued from early time because of certain properties. This soft silver-gray metal could be converted into a superhard substance that would cut glass and many other substances, including itself when soft. Furthermore, its hardness could be controlled. This converting of carbon steel into a steel of useful hardness is done with different heat treatments, two of the most important of which are hardening and tempering (drawing), which you will investigate in this lesson.Hardening by quenchingAs steel is heated above the lower critical temperature of 1330F (721C), the carbon that was in the form of layers of iron carbide in pearlite begins to dissolve in the iron and form a solid solution called austenite. When this solution of iron and carbon is suddenly cooled or quenched, a new microstructure is formed. This is called martensite. Martensite is very hard and brittle, having a much higher tensile strength than the steel with a pearlite microstructure. It is quite unstable, however, and must be tempered (drawn) to relieve internal stresses in order to have the ductility and toughness needed to be useful. AISI-C1095, commonly known as water-hardening tool (W1) steel, will begin to show hardness when quenched from a temperature just over 1330F (721C) but will not harden at all if quenched from a temperature lower than 1330F (721C). This steel will become as hard as it can get when heated to 1450F (788C) and quenched in water. This quenching temperature changes as the carbon content changes. It should be 50F (28C) above the upper critical temperature for carbon steels containing less than 0.83 percent carbon. The reason carbon steel ,less than eutectoid, should be heated above theupper critical temperature is that the ferrite is not all transformed into austenite below this point, and when quenched, is retained in the martensitic structure. The retained ferrite causes brittleness even after tempering.Low carbon steels such as AISI 1020 will not, for all practical purpose, harden when they are heated and quenched. Oil- and air-hardening steels have a higher hardenability and do not have to be quenched as rapidly as plain carbon steels. Consequently, they are deeper hardening than water hardening types, which must be cooled to 200F within 1 or 2 seconds. Plain carbon steels containing 0.83 percent carbon can get as hard (RC67) as any plain carbon steel containing more carbon.TemperingTempering, or drawing, is a process of reheating a steel part that has been previously hardened to transform some of the hard martensite into softer structures. The higher the tempering temperature used, the more martensite is transformed, and the softer and tougher (less brittle) the piece becomes. Therefore, tempering temperatures are specified according to the strength and ductility desired. Mechanical properties charts, which may be found in steel manufacturers’handbooks and catalogs, give these data for each type of alloy steel.A part can be tempered in a furnace or oven by bringing it to the required temperature and holding it there for a length of time, then cooling it in air or water. Some tool steels should be cooled rapidly after tempering to avoid temper brittleness.Tempering should be done as soon as possible after hardening. The part should not be allowed to cool completely, since untempered it contains very high internal stresses and tends to split or crack. Tempering will relieve the internal stresses. A hardened part left overnight without tempering may develop cracks by itself.New words 学习1.hardening 淬火2.temper 回火3.convert 转变4.value 重视，尊重……Notes1. This soft silver-gray metal could be converted into a superhard substance that would cut glass and many other substances, including itself when soft.这种银灰色的软金属能够转变成一种超硬的物质，该物质可以切削玻璃和许多其它物质，包括处于软状态时的该金属本身。
《机械专业英语unit》课件
Example analysis
Case Studies
Analyze real world case studies to demonstrate practical applications of mechanical writing
Compare and Contrast
Compare different writing styles and techniques to identify best practices
Standard expression: Mechanical English requires standardized and rigorous expression, in accordance with industry standards.
02
Common vocabulary and expressions in mechanical engineering English
Language accuracy
Use precision language and avoid technical errors
Clarity
Use simple language and avoid jargon to ensure the reader easily understands the content
Writing Standards
01
02
03
04
APA Style: Follow the American Psychological Association (APA) style guide for formatting and citations
APA Style: Follow the American Psychological Association (APA) style guide for formatting and citations
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Lesson 1 Mechanical Properties of Metals
Mechanical properties are the characteristic responses of a material to applied forces. These properties fall into five broad categories: strength, hardness, elasticity, ductility, and toughness.
Strength is the ability of a metal to resist applied forces.
Strength properties are commonly referred to as tensile strength, bending strength, compressive strength, torsional strength, shear strength and fatigue strength.
Tensile strength is that property which resists forces acting to pull the metal apart. It is one of more important factors in the evaluation of a metal.
Compressive strength is the ability of a material to resist being crushed. Compression is the opposite of tension with respect to the direction of the applied load. Most metals have high tensile strength and high compressive strength. However, brittle materials such as cast iron have high compressive strength but only a moderate tensile strength.
Bending strength is that quality which resists forces from causing a member to bend or deflect in the direction in which the load is applied. Actually a bending stress is a combination of tensile and compressive stresses.
Torsional strength is the ability of a metal to withstand forces that cause a member to twist.
Shear strength refers to how well a member can withstand two equal forces acting in opposite directions.
Fatigue strength is the property of a material to resist various kinds of rapidly alternating stresses. For example, a piston rod or an axle undergoes complete reversal of stresses from tension to compression. Bending a piece of wire back and forth until it breaks is another example
of fatigue strength.
Hardness is that property in steel which resists indentation or penetration. Hardness is usually expressed in terms of the area of an indentation made by a special ball under a standard load, or the depth of a special indenter under a specific load.
Elasticity is the ability to spring back to original shape. Auto bumpers and all springs should have this quality.
Ductility is the ability to undergo permanent changes of shape without rupturing. Modern, deep-formed auto bodies and fenders, and other stamped and formed products must have this property.
Toughness is the ability to absorb mechanically applied energy. Strength and ductility determine a material’s toughness. Toughness is needed in railroad cars, automobile axles, hammers, rails, and similar products.
New Words学习
1.Mechanical 力学的，机械的
2.Response 反应，响应，答复
3.Broad 主要的，概括的
4.Category 种类，类别
……
Notes
1.Tensile strength is that property which resists forces acting
to pull the metal apart.
抗拉强度是金属抵抗外力把它拉断的能力。
句中关系代词which 引导一定语从句修饰property。
在从句中which 作主语。
此外，在该从句中，现在分词短语acting to pull the metal apart 作定语修饰forces。
Pull……apart意为“把……拉开，把……拉断”。
pression is the opposite of tension with respect to the direction of the applied load.
压缩时载荷的方向与拉伸时的载荷方向相反。
该句中介词短语with respect to the direction of the applied load 作全句的状语。
3.Hardness is usually expressed in terms of the area of an indentation made by a special ball under a standard load, or the depth of a special indenter under a specific load.
硬度通常用在标准载荷作用下特制球产生的压痕面积来表示，或用特定载荷下专门压头所形成的深度来表示。
句中the area…a standard load和the depth…a specific load为并列的两个名词性短语，通过等立连词or连接，它们都是短语介词in terms of 的宾语。
介词短语in terms of…a specific load作全句的状语。