机械方面论文翻译
Manufacturing Engineering and Technology(机械类英文文献+翻译)
Manufacturing Engineering and Technology—MachiningSerope kalpakjian；Steven R.Schmid机械工业出版社2004年3月第1版20.9 MACHINABILITYThe machinability of a material usually defined in terms of four factors:1、Surface finish and integrity of the machined part;2、Tool life obtained;3、Force and power requirements;4、Chip control.Thus, good machinability good surface finish and integrity, long tool life, and low force And power requirements. As for chip control, long and thin (stringy) cured chips, if not broken up, can severely interfere with the cutting operation by becoming entangled in the cutting zone.Because of the complex nature of cutting operations, it is difficult to establish relationships that quantitatively define the machinability of a material. In manufacturing plants, tool life and surface roughness are generally considered to be the most important factors in machinability. Although not used much any more, approximate machinability ratings are available in the example below.20.9.1 Machinability Of SteelsBecause steels are among the most important engineering materials (as noted in Chapter 5), their machinability has been studied extensively. The machinability of steels has been mainly improved by adding lead and sulfur to obtain so-called free-machining steels.Resulfurized and Rephosphorized steels. Sulfur in steels forms manganese sulfide inclusions (second-phase particles), which act as stress raisers in the primary shear zone. As a result, the chips produced break up easily and are small; this improves machinability. The size, shape, distribution, and concentration of these inclusions significantly influence machinability. Elements such as tellurium and selenium, which are both chemically similar to sulfur, act as inclusion modifiers inresulfurized steels.Phosphorus in steels has two major effects. It strengthens the ferrite, causing increased hardness. Harder steels result in better chip formation and surface finish. Note that soft steels can be difficult to machine, with built-up edge formation and poor surface finish. The second effect is that increased hardness causes the formation of short chips instead of continuous stringy ones, thereby improving machinability.Leaded Steels. A high percentage of lead in steels solidifies at the tip of manganese sulfide inclusions. In non-resulfurized grades of steel, lead takes the form of dispersed fine particles. Lead is insoluble in iron, copper, and alumin um and their alloys. Because of its low shear strength, therefore, lead acts as a solid lubricant (Section 32.11) and is smeared over the tool-chip interface du ring cutting. This behavior has been verified by the presence of high concentra tions of lead on the tool-side face of chips when machining leaded steels.When the temperature is sufficiently high-for instance, at high cutting spee ds and feeds (Section 20.6)—the lead melts directly in front of the tool, acting as a liquid lubricant. In addition to this effect, lead lowers the shear stress in the primary shear zone, reducing cutting forces and power consumption. Lead can be used in every grade of steel, such as 10xx, 11xx, 12xx, 41xx, etc. Le aded steels are identified by the letter L between the second and third numeral s (for example, 10L45). (Note that in stainless steels, similar use of the letter L means “low carbon,”a condition that improves their corrosion resistance.)However, because lead is a well-known toxin and a pollutant, there are se rious environmental concerns about its use in steels (estimated at 4500 tons of lead consumption every year in the production of steels). Consequently, there is a continuing trend toward eliminating the use of lead in steels (lead-free ste els). Bismuth and tin are now being investigated as possible substitutes for lea d in steels.Calcium-Deoxidized Steels. An important development is calcium-deoxidize d steels, in which oxide flakes of calcium silicates (CaSo) are formed. These f lakes, in turn, reduce the strength of the secondary shear zone, decreasing tool-chip interface and wear. Temperature is correspondingly reduced. Consequently, these steels produce less crater wear, especially at high cutting speeds.Stainless Steels. Austenitic (300 series) steels are generally difficult to mac hine. Chatter can be s problem, necessitating machine tools with high stiffness. However, ferritic stainless steels (also 300 series) have good machinability. M artensitic (400 series) steels are abrasive, tend to form a built-up edge, and req uire tool materials with high hot hardness and crater-wear resistance. Precipitati on-hardening stainless steels are strong and abrasive, requiring hard and abrasio n-resistant tool materials.The Effects of Other Elements in Steels on Machinability. The presence of aluminum and silicon in steels is always harmful because these elements com bine with oxygen to form aluminum oxide and silicates, which are hard and a brasive. These compounds increase tool wear and reduce machinability. It is es sential to produce and use clean steels.Carbon and manganese have various effects on the machinability of steels, depending on their composition. Plain low-carbon steels (less than 0.15% C) c an produce poor surface finish by forming a built-up edge. Cast steels are mor e abrasive, although their machinability is similar to that of wrought steels. To ol and die steels are very difficult to machine and usually require annealing pr ior to machining. Machinability of most steels is improved by cold working, w hich hardens the material and reduces the tendency for built-up edge formation.Other alloying elements, such as nickel, chromium, molybdenum, and vana dium, which improve the properties of steels, generally reduce machinability. T he effect of boron is negligible. Gaseous elements such as hydrogen and nitrog en can have particularly detrimental effects on the properties of steel. Oxygen has been shown to have a strong effect on the aspect ratio of the manganese sulfide inclusions; the higher the oxygen content, the lower the aspect ratio an d the higher the machinability.In selecting various elements to improve machinability, we should consider the possible detrimental effects of these elements on the properties and strengt h of the machined part in service. At elevated temperatures, for example, lead causes embrittlement of steels (liquid-metal embrittlement, hot shortness; see Se ction 1.4.3), although at room temperature it has no effect on mechanical prop erties.Sulfur can severely reduce the hot workability of steels, because of the fo rmation of iron sulfide, unless sufficient manganese is present to prevent such formation. At room temperature, the mechanical properties of resulfurized steels depend on the orientation of the deformed manganese sulfide inclusions (aniso tropy). Rephosphorized steels are significantly less ductile, and are produced so lely to improve machinability.20.9.2 Machinability of Various Other MetalsAluminum is generally very easy to machine, although the softer grades te nd to form a built-up edge, resulting in poor surface finish. High cutting speed s, high rake angles, and high relief angles are recommended. Wrought aluminu m alloys with high silicon content and cast aluminum alloys may be abrasive; they require harder tool materials. Dimensional tolerance control may be a pro blem in machining aluminum, since it has a high thermal coefficient of expans ion and a relatively low elastic modulus.Beryllium is similar to cast irons. Because it is more abrasive and toxic, t hough, it requires machining in a controlled environment.Cast gray irons are generally machinable but are. Free carbides in castings reduce their machinability and cause tool chipping or fracture, necessitating to ols with high toughness. Nodular and malleable irons are machinable with hard tool materials.Cobalt-based alloys are abrasive and highly work-hardening. They require sharp, abrasion-resistant tool materials and low feeds and speeds.Wrought copper can be difficult to machine because of built-up edge form ation, although cast copper alloys are easy to machine. Brasses are easy to ma chine, especially with the addition pf lead (leaded free-machining brass). Bronz es are more difficult to machine than brass.Magnesium is very easy to machine, with good surface finish and prolong ed tool life. However care should be exercised because of its high rate of oxi dation and the danger of fire (the element is pyrophoric).Molybdenum is ductile and work-hardening, so it can produce poor surfac e finish. Sharp tools are necessary.Nickel-based alloys are work-hardening, abrasive, and strong at high tempe ratures. Their machinability is similar to that of stainless steels.Tantalum is very work-hardening, ductile, and soft. It produces a poor surf ace finish; tool wear is high.Titanium and its alloys have poor thermal conductivity (indeed, the lowest of all metals), causing significant temperature rise and built-up edge; they can be difficult to machine.Tungsten is brittle, strong, and very abrasive, so its machinability is low, although it greatly improves at elevated temperatures.Zirconium has good machinability. It requires a coolant-type cutting fluid, however, because of the explosion and fire.20.9.3 Machinability of Various MaterialsGraphite is abrasive; it requires hard, abrasion-resistant, sharp tools.Thermoplastics generally have low thermal conductivity, low elastic modul us, and low softening temperature. Consequently, machining them requires tools with positive rake angles (to reduce cutting forces), large relief angles, small depths of cut and feed, relatively high speeds, and proper support of the work piece. Tools should be sharp.External cooling of the cutting zone may be necessary to keep the chips f rom becoming “gummy”and sticking to the tools. Cooling can usually be achi eved with a jet of air, vapor mist, or water-soluble oils. Residual stresses may develop during machining. To relieve these stresses, machined parts can be an nealed for a period of time at temperatures ranging from to ( to ), and then cooled slowly and uniformly to room temperature.Thermosetting plastics are brittle and sensitive to thermal gradients during cutting. Their machinability is generally similar to that of thermoplastics.Because of the fibers present, reinforced plastics are very abrasive and are difficult to machine. Fiber tearing, pulling, and edge delamination are significa nt problems; they can lead to severe reduction in the load-carrying capacity of the component. Furthermore, machining of these materials requires careful rem oval of machining debris to avoid contact with and inhaling of the fibers.The machinability of ceramics has improved steadily with the development of nanoceramics (Section 8.2.5) and with the selection of appropriate processi ng parameters, such as ductile-regime cutting (Section 22.4.2).Metal-matrix and ceramic-matrix composites can be difficult to machine, d epending on the properties of the individual components, i.e., reinforcing or wh iskers, as well as the matrix material.20.9.4 Thermally Assisted MachiningMetals and alloys that are difficult to machine at room temperature can be machined more easily at elevated temperatures. In thermally assisted machinin g (hot machining), the source of heat—a torch, induction coil, high-energy bea m (such as laser or electron beam), or plasma arc—is forces, (b) increased too l life, (c) use of inexpensive cutting-tool materials, (d) higher material-removal rates, and (e) reduced tendency for vibration and chatter.It may be difficult to heat and maintain a uniform temperature distribution within the workpiece. Also, the original microstructure of the workpiece may be adversely affected by elevated temperatures. Most applications of hot machi ning are in the turning of high-strength metals and alloys, although experiment s are in progress to machine ceramics such as silicon nitride.SUMMARYMachinability is usually defined in terms of surface finish, tool life, force and power requirements, and chip control. Machinability of materials depends n ot only on their intrinsic properties and microstructure, but also on proper sele ction and control of process variables.20.9 可机加工性一种材料的可机加工性通常以四种因素的方式定义：1、分的表面光洁性和表面完整性。
机械的工作英文作文
机械的工作英文作文英文：As a mechanical engineer, my work involves designing, developing, and testing mechanical devices and systems. This can range from simple machines like gears and pulleys to complex systems like engines and robots. I work closely with other engineers and technicians to ensure that the products we create meet the needs of our clients and are safe and reliable.One of the most challenging aspects of my job is troubleshooting. When a machine or system isn't working properly, it's up to me to figure out what's causing the problem and come up with a solution. This often involves a lot of trial and error, as well as creative thinking and problem-solving skills.Another important part of my job is staying up-to-date with the latest technology and industry trends. This meansattending conferences and workshops, reading industry publications, and networking with other professionals in my field. By staying informed, I can ensure that the products I design and develop are cutting-edge and meet the needs of our clients.Overall, my job as a mechanical engineer is challenging but rewarding. I enjoy the problem-solving aspect of my work and the satisfaction of seeing a project through from conception to completion.中文：作为一名机械工程师，我的工作涉及设计、开发和测试机械设备和系统。
机械类英语作文模板
机械类英语作文模板英文回答：Introduction。
Mechanical engineering is an incredibly vast anddiverse field that encompasses the design, development, and operation of machines. It is a highly interdisciplinaryfield that draws upon principles from physics, mathematics, and materials science to create solutions to real-world problems. Mechanical engineers play a vital role in many industries, including transportation, manufacturing, energy, and healthcare.Education and Training。
To become a mechanical engineer, a strong foundation in mathematics and science is essential. Most mechanical engineers hold a bachelor's degree in mechanicalengineering from an accredited university. Some may alsochoose to pursue a master's degree or doctorate in mechanical engineering or a related field.Career Opportunities。
Mechanical engineers are in high demand across a wide range of industries. Some of the most common job titles for mechanical engineers include:Design Engineer。
机械作文300字英文
机械作文300字英文英文：Mechanical engineering is a fascinating field that involves the design, development, and manufacturing of various types of machinery. As a mechanical engineer, I have had the opportunity to work on a wide range of projects, from designing and building robots to developing new types of engines for cars.One of the most interesting projects I have worked on was designing a new type of prosthetic arm for amputees. This involved working closely with medical professionals and amputees themselves to understand their needs and design a prosthetic that would be both functional and comfortable to wear. We used advanced materials and manufacturing techniques to create a lightweight and durable prosthetic that could be customized to fit each individual's needs.Another project that I found particularly challenging was designing a new type of engine for a hybrid car. This involved balancing the need for power and efficiency while also considering environmental factors such as emissions. We used computer simulations and physical testing to optimize the design and ended up with an engine that was both powerful and environmentally friendly.Overall, I love being a mechanical engineer because it allows me to use my creativity and problem-solving skills to design and build things that make a difference in people's lives.中文：机械工程是一个迷人的领域，涉及各种类型机械的设计、开发和制造。
机械专业英语短文带翻译
机械工程师的关键责任之一是设计与分析机械系统。这涉及使用计算机辅助设计（CAD）软件创建系统的详细三维模型，并在不同条件下模拟其性能。通过分析作用于系统组件的力、应力和振动，机械工程师可以优化设计，确保安全、可靠和高效。
Case Study: Designing an Automotive Suspension System
案例研究：汽车悬挂系统设计
例如，让我们考虑一下汽车悬挂系统的设计。悬挂系统负责在保持车辆稳定控制的同时提供平稳的行驶。机械工程师使用CAD软件设计悬挂系统的各个组件，例如弹簧、减振器和控制臂。
在完成初始设计后，工程师将使用有限元分析（FEA）软件对系统进行分析。这样可以模拟系统在不同的道路条件下（如坑洼或减速带）的行为。通过分析组件中的应力和位移，工程师可以确定潜在的设计问题，并进行必要的修改，以改善悬挂系统的性能和安全性。
For example, let's consider the design of an automotive suspension system. A suspension system is responsible for providing a smooth ride while maintaining the stability and control of the vehicle. A mechanical engineer would use CAD software to design the various components of the suspension system, such as the springs, dampers, and control arms.
After the initial design is complete, the engineer would then analyze the system using finite element analysis (FEA) software. This allows them to simulate the behavior of the system under different road conditions, such as potholes or speed bumps. By analyzing the stresses and displacements in the components, the engineer can identify potential design issues and make necessary modifications to improve the performance and safety of the suspension system.
机械专业毕业论文中英文翻译--在全接触条件下,盘式制动器摩擦激发瞬态热弹性不稳定的研究
Frictionally excited thermoelastic instability in disc brakes—Transientproblem in the full contact regimeAbstractExceeding the critical sliding velocity in disc brakes can cause unwanted forming of hot spots, non-uniform distribution of contact pressure, vibration, and also, in many cases, permanent damage of the disc. Consequently, in the last decade, a great deal of consideration has been given to modeling methods of thermo elastic instability (TEI), which leads to these effects. Models based on the finite element method are also being developed in addition to the analytical approach. The analytical model of TEI development described in the paper by Lee and Barber [Frictionally excited thermo elastic instability in automotive disk brakes. ASME Journal of Tribology 1993;115:607–14] has been expanded in the presented work. Specific attention was given to the modification of their model, to catch the fact that the arc length of pads is less than the circumference of the disc, and to the development of temperature perturbation amplitude in the early stage of breaking, when pads are in the full contact with the disc. A way is proposed how to take into account both of the initial non-flatness of the disc friction surface and change of the perturbation shape inside the disc in the course of braking.Keywords: Thermo elastic instability; TEI; Disc brake; Hot spots1. IntroductionFormation of hot spots as well as non-uniform distribution of the contact pressure is an unwanted effect emerging in disc brakes in the course of braking or during engagement of a transmission clutch. If the sliding velocity is high enough, this effect can become unstable and can result in disc material damage, frictional vibration, wear, etc. Therefore, a lot of experimental effort is being spent to understand better this effect (cf. Refs.) or to model it in the most feasible fashion. Barber described the thermo elastic instability (TEI)as the cause of the phenomenon. Later Dow and Burton and Burton et al.introduced a mathematical model to establish critical sliding velocity for instability, where two thermo elastic half-planes are considered in contact along their common interface. It is in a work by Lee and Barber that the effect of the thickness was considered and that a model applicable for disc brakes was proposed. Lee and Barber’s model is made up with a metallic layer sliding between twohalf-planes of frictional material. Only recently a parametric analysis of TEI in disc brakes was made or TEI in multi-disc clutches and brakes was modeled. The evolution of hot spots amplitudes has been addressed in Refs. Using analytical approach or the effect of intermittent contact was considered. Finally, the finite element method was also applied to render the onset of TEI (see Ref.).The analysis of nonlinear transient behavior in the mode, when separated contact regions occur, is even accomplished in Ref. As in the case of other engineering problems of instability, it turns out that a more accurate prediction by mathematical modeling is often questionable. This is mainly imparted by neglecting various imperfections and random fluctuations or by the impossibility to describe all possible influences appropriately. Therefore, some effort aroused to interpret results of certain experiments in addition to classical TEI (see, e.g.Ref).This paper is related to the work by Lee and Barber [7].Using an analytical approach, it treats the inception of TEI and the development of hot spots during the full contact regime in the disc brakes. The model proposed in Section 2 enables to cover finite thickness of both friction pads and the ribbed portion of the disc. Section 3 is devoted to the problems of modeling of partial disc surface contact with the pads. Section 4 introduces the term of ‘‘thermal capacity of perturbation’’ emphasizing its association with the value of growth rate, or the sliding velocity magnitude. An analysis of the disc friction surfaces non-flatness and its influence on initial amplitude of perturbations is put forward in the Section 5. Finally, the Section 6 offers a model of temperature perturbation development initiated by the mentioned initial discnon-flatness in the course of braking. The model being in use here comes from a differential equation that covers the variation of the‘‘thermal capacity’’ during the full contact regime of the braking.2. Elaboration of Lee and Barber modelThe brake disc is represented by three layers. The middle one of thickness 2a3 stands for the ribbed portion of the disc with full sidewalls of thickness a2 connected to it. The pads are represented by layers of thickness a1, which are immovable and pressed to each other by a uniform pressure p. The brake disc slips in between these pads at a constant velocity V.We will investigate the conditions under which a spatially sinusoidal perturbation in the temperature and stress fields can grow exponentially with respect to the time in a similar manner to that adopted by Lee and Barber. It is evidenced in their work [7] that it is sufficient to handle only the antisymmetric problem. The perturbations that are symmetric with respect to the midplane of the disc can grow at a velocity well above the sliding velocity V thus being made uninteresting.Let us introduce a coordinate system （x1; y1）fixed to one of the pads (see Fig. 1) thepoints of contact surface between the pad and disc having y1 = 0. Furthermore, let acoordinate system （x2; y2）be fixed to the disc with y2=0 for the points of the midplane. We suppose the perturbation to have a relative velocity ci with respect to the layer i, and the coordinate system （x; y）to move together with the perturbated field. Then we can writeV = c1 -c2; c2 = c3; x = x1 -c1t = x2 -c2t,x2 = x3; y = y2 =y3 =y1 + a2 + a3.We will search the perturbation of the uniform temperature field in the formand the perturbation of the contact pressure in the formwhere t is the time, b denotes a growth rate, subscript I refers to a layer in the model, and j =-1½is the imaginary unit. The parameter m=m（n）=2pin/cir =2pi/L, where n is the number of hot spots on the circumference of the disc cir and L is wavelength of perturbations. The symbols T0m and p0m in the above formulae denote the amplitudes of initial non-uniformities (e.g. fluctuations). Both perturbations (2) and (3) will be searched as complex functions their real part describing the actual perturbation of temperature or pressure field.Obviously, if the growth rate b<0, the initial fluctuations are damped. On the other hand, instability develops ifB〉0.2.1. Temperature field perturbationHeat flux in the direction of the x-axis is zero when the ribbed portion of the disc is considered. Next, let us denote ki = Ki/Qicpi coefficient of the layer i temperature diffusion. Parameters Ki, Qi, cpi are, respectively, the thermal conductivity, density and specific heat of the material for i =1,2. They have been re-calculated to the entire volume of the layer (i = 3) when the ribbed portion of the disc is considered. The perturbation of the temperature field is the solution of the equationsWith and it will meet the following conditions:1，The layers 1 and 2 will have the same temperature at the contact surface2，The layers 2 and 3 will reach the same temperature and the same heat flux in the direction y,3，Antisymmetric condition at the midplaneThe perturbations will be zero at the external surface of a friction pad(If, instead, zero heat flux through external surface has been specified, we obtain practically identical numerical solution for current pads).If we write the temperature development in individual layers in a suitable formwe obtainwhereand2.2. Thermo elastic stresses and displacementsFor the sake of simplicity, let us consider the ribbed portion of the disc to be isotropic environment with corrected modulus of elasticity though, actually, the stiffness of this layer in the direction x differs from that in the direction y. Such simplification is, however, admissible as the yielding central layer 3 practically does not take effect on the disc flexural rigidity unlike full sidewalls (layer 2). Given a thermal field perturbation, we can express the stress state and displacements caused by this perturbation for any layer. The thermo elastic problem can be solved by superimposing a particular solution on the general isothermal solution. We look for the particular solution of a layer in form of a strain potential. The general isothermal solution is given by means of the harmonic potentials after Green and Zerna (see Ref.[18]) and contains four coefficients A, B, C, D for every layer. The relateddisplacement and stress field components are written out in the Appendix A.在全接触条件下，盘式制动器摩擦激发瞬态热弹性不稳定的研究摘要超过临界滑动盘式制动器速度可能会导致形成局部过热，不统一的接触压力，振动分布，而且，在多数情况下，会造成盘式制动闸永久性损坏。
机械类英语论文及翻译
Mechanical DesignAbstract:A machine is a combination of mechanisms and other components which transforms, transmits. 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. The term "mechanical design" is used in a broader sense than "machine design" to include their design. 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 Design ；Rules for Design ；Design ProcessThe Design ProcessDesigning starts with a need real.Existing apparatus may need improvements in durability, efficiency, weight, speed, or cost. New apparatus may be needed to perform a function previously done by men, such as computation, assembly, or servicing. With the objective wholly or partly.In the design preliminary stage, should allow to design the personnel fullyto display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the plan blueprint is corrected. Only then, only then does not send to stops up the innovation the mentality. Usually, must propose several sets of design proposals, then perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts.When the general shape and a few dimensions of the several components become apparent, analysis can begin in earnest. The analysis will have as its objective satisfactory or superior performance, plus safety and durability with minimum weight, and a competitive cost. Optimum proportions and dimensions will be sought for each critically loaded section, together with a balance between the strengths of the several components. Materials and their treatment will be chosen. These important objectives can be attained only by analysis based upon the principles of mechanics, such as those of static for reaction forces and for the optimum utilization of friction; of dynamics for inertia, acceleration, and energy; of elasticity and strength of materials for stress and deflection; of physical behavior of materials; and of fluid mechanics for lubrication and hydrodynamic drives. The analyses may be made by the same engineer who conceived the arrangement of mechanisms, or, in a large company, they may be made by a separate analysis division or research group. Design is a reiterative and cooperative process, whetherdone formally or informally, and the analyst can contribute to phases other than his own. Product design requires much research and development. Many Concepts of an idea must be studied, tried, and then either used or discarded. Although the content of each engineering problem is unique, the designers follow the similar process to solve the problems.Product liability suits designers and forced in material selection, using the best program. In the process of material, the most common problems for five (a) don't understand or not use about the latest application materials to the best information, (b) failed to foresee and consider the reasonable use material may (such as possible, designers should further forecast and consider due to improper use products. In recent years, many products liability in litigation, the use of products and hurt the plaintiff accused manufacturer, and won the decision), (c) of the materials used all or some of the data, data, especially when the uncertainty long-term performance data is so, (d) quality control method is not suitable and unproven, (e) by some completely incompetent persons choose materials.Through to the above five questions analysis, may obtain these questions is does not have the sufficient reason existence the conclusion. May for avoid these questions to these questions research analyses the appearance indicating the direction. Although uses the best choice of material method not to be able to avoid having the product responsibility lawsuit, designs the personnel and the industry carries on the choice of material according to thesuitable procedure, may greatly reduce the lawsuit the quantity.May see from the above discussion, the choice material people should to the material nature, the characteristic and the processing method have comprehensive and the basic understanding.Finally, a design based upon function, and a prototype may be built. If its tests are satisfactory, the initial design will undergo certain modifications that enable it to be manufactured in quantity at a lower cost. During subsequent years of manufacture and service, the design is likely to undergo changes as new ideas are conceived or as further analyses based upon tests and experience indicate alterations. Sales appeal.Some Rules for DesignIn this section it is suggested that, applied with a creative attitude, analyses can lead to important improvements and to the conception and perfection of alternate, perhaps more functional, economical,and durable products.To stimulate creative thought, the following rules are suggested for the designer and analyst. The first six rules are particularly applicable for the analyst.1. A creative use of need of physical properties and control process.2. Recognize functional loads and their significance.3. Anticipate unintentional loads.4. Devise more favorable loading conditions.5. Provide for favorable stress distribution and stiffness with minimum weight.6. Use basic equations to proportion and optimize dimensions.7. Choose materials for a combination of properties.8. Select carefully, stock and integral components.9. Modify a functional design to fit the manufacturing process and reduce cost.10. Provide for accurate location and noninterference of parts in assembly.Machinery design covers the following contents.1. Provides an introduction to the design process , problem formulation ,safety factors.2. Reviews the material properties and static and dynamic loading analysis ,Including beam , vibration and impact loading.3. Reviews the fundamentals of stress and defection analysis.4. Introduces fatigue-failure theory with the emphasis on stress-life approaches to high-cycle fatigue design, which is commonly used in the design of rotation machinery.5. Discusses thoroughly the phenomena of wear mechanisms, surface contact stresses ,and surface fatigue.6. Investigates shaft design using the fatigue-analysis techniques.7. Discusses fluid-film and rolling-element bearing theory and application8. Gives a thorough introduction to the kinematics, design and stress analysis of spur gears , and a simple introduction to helical ,bevel ,and worm gearing.9. Discusses spring design including compression ,extension and torsion springs.10. Deals with screws and fasteners including power screw and preload fasteners.11. Introduces the design and specification of disk and drum clutches and brakes.Machine DesignThe complete design of a machine is a complex process. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kinematics, engineerig material, materials mechanics and machine manufacture technology has the deep elementary knowledge.One of the first steps in the design of any product is to select the material from which each part is to be made. Numerous materials are available to today's designers. The function of the product, its appearance, the cost of thematerial, and the cost of fabrication are important in making a selection. A careful evaluation of the properties of a. material must be made prior to any calculations.Careful calculations are necessary to ensure the validity of a design. In case of any part failures, it is desirable to know what was done in originally designing the defective components. The checking of calculations (and drawing dimensions) is of utmost importance. The misplacement of one decimal point can ruin an otherwise acceptable project. All aspects of design work should be checked and rechecked.The computer is a tool helpful to mechanical designers to lighten tedious calculations, and provide extended analysis of available data. Interactive systems, based on computer capabilities, have made possible the concepts of computer aided design (CAD) and computer-aided manufacturing (CAM). How does the psychologist frequently discuss causes the machine which the people adapts them to operate. Designs personnel''s basic responsibility is diligently causes the machine to adapt the people. This certainly is not an easy work, because certainly does not have to all people to say in fact all is the most superior operating area and the operating process. Another important question, project engineer must be able to carry on the exchange and the consultation with other concerned personnel. In the initial stage, designs the personnel to have to carry on the exchange and the consultation on the preliminary design with the administrative personnel, and is approved.This generally is through the oral discussion, the schematic diagram and the writing material carries on.If front sues, the machine design goal is the production can meet the human need the product. The invention, the discovery and technical knowledge itself certainly not necessarily can bring the advantage to the humanity, only has when they are applied can produce on the product the benefit. Thus, should realize to carries on before the design in a specific product, must first determine whether the people do need this kind of productMust regard as the machine design is the machine design personnel carries on using creative ability the product design, the system analysis and a formulation product manufacture technology good opportunity. Grasps the project elementary knowledge to have to memorize some data and the formula is more important than. The merely service data and the formula is insufficient to the completely decision which makes in a good design needs. On the other hand, should be earnest precisely carries on all operations. For example, even if places wrong a decimal point position, also can cause the correct design to turn wrongly.A good design personnel should dare to propose the new idea, moreover is willing to undertake the certain risk, when the new method is not suitable, use original method. Therefore, designs the personnel to have to have to have the patience, because spends the time and the endeavor certainlycannot guarantee brings successfully. A brand-new design, the request screen abandons obsoletely many, knows very well the method for the people. Because many person of conservativeness, does this certainly is not an easy matter. A mechanical designer should unceasingly explore the improvement existing product the method, should earnestly choose originally, the process confirmation principle of design in this process, with has not unified it after the confirmation new idea.外文论文翻译译文机械设计摘要：机器是由机械装置和其它组件组成的。
机械类英语论文及翻译
机械类英语论文及翻译Mechanical design involves the n of machines。
which are composed of mechanisms and other components that can transform and transmit ___ machines include engines。
turbines。
vehicles。
hoists。
printing presses。
washing machines。
and ___ and methods of design that apply to machines also apply to ___。
the term "mechanical design" is used in a broader sense than "machine design" to include their design.When ___。
___ to take into account。
The n and structural aspects of the device。
as well as the ___。
___ apply not only to machines but also to other mechanical devices。
such as switches。
cams。
valves。
vessels。
and mixers.Mechanical design is a critical field in ___ disciplines。
It plays an essential role in the ___ the success of a mechanical design project。
it is essential to follow a set of rules for design。
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用自动化机器翻译的指标来分析文章转化形式的影响Johann Roturier Linda MitchellSymantec Research Labs SALISBallycoolin Business Park Dublin City University Blanchardstown, Dublin 15, Ireland Ballymun, Dublin 9, Irelandjohann_roturier@ linda.mitchell7@mail.dcu.ie Robert Grabowski, Melanie SiegelAcrolinx GmbHFriedrichstr. 100, 10117 Berlin, Germany{robert.grabowski,melanie.siegel}@摘要本文研究的是当分析源转化形式对翻译机器的质量影响的同时，自动翻译器翻译的用户输入的内容的有用性，我们提出了一个新的框架，试图依靠自动检测，而不是人的判断，用来快速识别那些改善或降低质量的输出的改写规则。
我们发现，这种方法使我们能够快速识别两种语言之间的重叠规则（英语-法语和英语-德语）和某些具体情况下的规律精度还有待改进。
1引言软件出版商依靠手册和在线支持（知识库）的文章，以帮助他们的用户进行产品的安装，维护或排除故障。
随着Web2.0沟通渠道的出现，然而，这些文档集已经用用户生成衍生的内容（UGC）进行了补充。
现在，用户在相关软件产品内容的衍生上都非常活跃，尤其是在网上论坛，精明的用户在这里互相询问和交流问题以及解决方法。
虽然此类论坛特定语言版本有时会存在，大部分内容是很经常用英文写的，可能需要翻译成对任何用户都有用的。
然而这样的内容有时是机器翻译，一些理解问题可能存在。
这些目标端的理解问题可以被下列信息源端的UGC的特性所引起：源文章的内容可能会被写成非专业术语还是非母语（因此它的语言和技术的准确性可能不好）。
即使是书面语，这些有着正规的语法和词汇的创意的内容更接近口语部分。
文章的一些内容是由“技术精英的态度指导的，展现交流技术的（Leblanc , 2005），”有能力的用户所写的。
这些措施包括替代拼写，缩写，情况的变化，技术条款，表情符号，或者非词汇存在时的声音表示。
在本文中，我们提出了一个新的框架来快速评估具体再形成对机器翻译质量的影响。
该框架提供的再形成都与第2节提出的有一定的联系。
这项工作是在ACCEPT项目2范围内进行，其目的是使机器翻译适应新兴社区内容，使整个欧盟的公民更好地在商业和非营利性的社区环境访问。
2.相关的工作重写或重新组织文章源的内容，使之机器翻译的成为一个更加活跃的研究领域。
几种方法已被沿用到今天：源代码标准化，源代码重新排序和源代码控制。
我们的框架提供了一种方法来评估这些方法在快速方式方面的影响。
2.1资料来源规范化源标准化可以使用多种技术来实现，包括那些在Banerjee等人所述（2012年）：使用规律的表达，拼写检查和融合单词的分割。
尽管这些技术用来减少OOV的单词是有效的，然而当误差密度较低时，他们对于BLEU分数的改善的影响有局限性。
句子标准化的另一个领域涉及与相似的句子替换句子。
鉴于大量文本数据中，句子集群可以找到类似的句子，有利于规范他们。
如果变量选择在训练数据的翻译机器上受训，可以确信的是为了防止源语言文本的变化，这些改变在机器翻译的训练数据下100%的匹配。
这个问题在于，用户自己生成的内容不是那么均匀，导致有效地使用这个方法可能很困难。
2.2 源重新排序另一种方法是重新排序源文本，使其在得到机器翻译之前，更加接近目标文本。
这种方法是由Collins等人提出建议的（2005）和包括Genzel的补充（2010年）。
虽然这种方法可以使翻译质量改进（尤其是在BLEU得分方面），这是不恰当的，当转换后的源文本必须发布（这可能是在用户生成内容的背景的情况下）。
2.3源代码控制对词汇，语法和风格的限制或约束的源代码控制（或控制语言），为了提高机器译源文本，在技术创作的领域已经使用了很长时间的（Bernth和Gdaniec2002）。
多项研究，包括O’Brien and Roturier （2007）和Aikawa et al 等人（2007）已经表明，这种方法确实可以使机器翻译的质量改进（无论是在可理解性或后期编辑的效率计算）。
由于一些规则是系统的，域的或特定语言的，它们必须在被用于新的方案之前重新评估。
然而，这样的评估可能是非常耗时和昂贵的，特别是如果两套参考翻译是必需的（Doherty ，2012）。
因此在这项研究中，我们有兴趣找出，是否有可能依靠自动度量快速识别有效的规则，而不是通过人的判断。
3系统和数据的说明3.1 数据在本文中所使用的测试集包含的2031句子对应于从英语诺顿论坛随机选定的250个职位（如Banerjee等描述的，2012）。
这些集合，接着由专业翻译人员翻译成法国和德国的参考译文翻译。
然后，由专业评审来审查这些翻译的语言和技术，以识别和纠正潜在的翻译错误。
这次审查的结果被用来作为第二参考译文集。
3.2 MT系统在这些实验中使用的MT系统是以短语为基础的摩西系统，用标准的摩西流水线进行训练。
翻译和重新排序模型与所有可用的并行的串联数据进行了培训，然而对于其语言模型来说，每个单独的模型在各自语言库单独训练，并且所有模型都穿插在一起最大限度地减少对调整设置的难度。
摩西标记化和套管工具被使用。
并行数据包括赛门铁克的翻译记忆库数据（含产品说明书，营销内容，知识库的内容和网站内容），辅以Europarl的WMT123发布的新闻评论。
对于语言模型，所有并行数据的目标两侧分别使用，以及来自赛门铁克论坛的单语资料。
单语的数据不包括在英国和德国的系统，因为它被发现并非改善BLEU得分。
由论坛数据组成的调整和测试数据的赛门铁克系统（500平行的句子），已被有着网上机器翻译系统机器翻译，并使用CNLG/ TAUS指引编辑了。
3.3资料源变化系统AC-rolinx软件是建立在语言分析引擎上，提供有关单语文本的规则资源（如布雷顿坎普等人，2000所述），以及拼写，语法，风格和术语检查。
编辑前的这些方法可以在一方面作者被应用，因为通常在技术文档编写过程中完成的。
笔者的错误标记和改进建议，并重新改变其形式。
这个过程确保了文本转换始终是正确的。
此外，让笔者开始一个学习的过程。
他或她更好的理解机器翻译本身的能力和限度。
在另一方面，它能够自动适用于所提供的建议，重新进行翻译。
不同技术文件的创作支持，这里的重点是更好的机器翻译结果。
自动应用规则的要快得多。
这个过程仅影响翻译，因此该应用程序的精度不那么重要。
对于本文的目的，Acrolinx软件进行了调整，以处理用户生成内容，专门处理外来语言错误，接近口语的内容和使用的“技术人员”的语言。
我们用所谓的“autoApplyClient”的独立工具将文档发送到一个Acrolinx服务器，检索结果，并自动通过其建议更换文档的标记部分，然后应用所有建议重新拟订。
客户端具有两个不同的输出模式。
在第一种模式，它适用于将所有建议放到同一个文件，并将结果写入到一个新的（单一）文件。
在第二种模式下，单独应用建议：为每一个可能改写，客户端输出原句，改写句子，错误类型（拼写，语法，样式或术语），以及应用名称语法或样式规律，或者已经使用的术语的变异。
对于评估，我们使用全球化的和以句子为基础的改写模式。
3.4 使用自动度量的评分为了快速识别预先编辑那些，看起来对MT的翻译质量有改善或降低作用的改写类型，我们使用自动度量的得分，改写文本的原件和翻译方面的参考译文。
为了得到对整个文档影响的首次评估，我们计算了以下成绩：（Lin和Och，2004）所有句子的平均平滑BLEU，翻译错误率（TER等人在Snover的描述，2006）和一般文本匹配器（GTM，在梅拉梅德等刊物上的描述，2003），包括精度，调用和F值分数。
对于在句子级别基础上的影响的第二次评估，我们计算每重新变化和原句的下列项目的分数：平滑BLEU，翻译错误率（TER），和一般文本匹配器（GTM）F值。
BLEU的“平滑”修改避免成为零的情况，即得分是N-gram不存在，一种常见的情况是以小尺寸为参考的，以句子为基础的评估。
此外，我们计算了用于翻译系统训练集建立的语言模型（LM）的得分。
通过训练集，给LM分数分段。
LM分数，对于摩西是确定最有可能的翻译的一个因素。
在这里，我们计算了包括文章源和目标语言训练集的LM得分，以下是两个假设：1.更好的源语言模型得分使得文本更“容易”进行翻译，因为它更类似于训练语言。
2.一个更好的目标语言模型的评分，意味着类似的目标语言的句子是“已经了解”语句，因而具有较高的翻译质量。
为了轻松获得评分结果，我们创建了一个结合了autoApplyClient，摩西SMT软件，以及不同的自动评分指标的框架，如图1图1：规则评估框架第二个实验侧重于每个单独重新变化的句子的分数。
因为绝对值在不同的指标和句子之间不具有可比性，我们简化了数据集的转换相对分数:对于每个重新组合的句子中，我们注意到得分相对于不重新配方的对应的原句分数是否有所改善，降级或保持不变。
注意，在分数方面影响的“量”不予考虑。
3.5 用于人类改革的分数在第二个实验中，有两个因素无疑是代表损害性结果的。
首先，在句子层面计算分数意味着小“错误判断”通过自动度量平整数据的大小检测不出。
其次，切换到一个相对更好的/等于/差的指标意味着改写的影响量的信息将丢失。
为消除这些影响，并对自动度量有一个更好地理解，我们首先过滤掉，对给定输入数据的改变不超过12个的所有规则。
对于其余规则的再形成，我们再进行人工评估。
评估者给予初始句子和改写句子的翻译，来判断哪个转换为更接近参考译文，或是否存在变化。
这个过程因此给另一组成绩好/等于/坏的规模。
有了这个“人指标”，我们能够检查自动度量是否与人的判断一致，在此之前，我们看基于自动计算分数的有巨大影响力的特定的规则。
4 自动改定实验及结果我们进行了两组实验：第一种包括对整个测试集自动重新拟订的。
第二轮实验中研究了个体建议水平上的分数。
4.1总体结果表1表示由自动应用客户端和源文本之间的差异量（以TER和GTM F值计算）改变句子（满分2031）数量：(in terms ofTER andGTMF-Measure):SentsTER GTM F-MeasureOriginal vs.Spelling150 0.0101 0.9804Original vs.Gram-mar67 0.0054 0.9901Original vs.Style328 0.0334 0.9529Original vs.Spelling+Grammar197 0.0157 0.9708Original vs.Spelling +Grammar +Style403 0.0483 0.9279表1：文本源的变化表1表面了语法重新配方（67）远没有拼写（150）或类型变化的频繁。