文档库 最新最全的文档下载
当前位置:文档库 › 外文翻译---机械零件强度

外文翻译---机械零件强度

外文翻译---机械零件强度
外文翻译---机械零件强度

附录2

外文原文

THE Strength of Mechianical Elements One of the primary considerations in designing any machine of structure is that the strength must be sufficiently greater than the stress to assure both safety and reliability. To assure do fail. Then we shall be able to relate the stresses with the strengths to achieve safety.

Ideally , in designing any machine clement, the engineer should have at his disposal the results of a great many strength tests of the particular material chosen. These tests shoule have been made on spccimens having the same heat treatment, surface roughness, and size as the element he proposes to design,and the tests should be made under exactly the same loading conditions as the part will experience in service. This means that, if the part is to experience a bending load, it should be tested with a bending load. If it is to be subjected to combined bending and torsion , it should be tested under combined bending and torsion. Such tests will provide very useful and precise information. They tell the engineer what factor of safety to use and what the reliability is for a gicen service life. Whenever such data are available for design purpses, the engineer can be assured that be is doing the best possible job of engineering. The cost of gathering such extensive data prior to design is justified if failure of the part may endanger human life, or if the part ia manufactured in sufficiently large quantities. Automobiles and refrigerators, for example,have very good reliabilities because the parts are made in such large quantities that they can be thoroughly tested in advance of manufacture. The cost of making these tests is very low when it is divided the total number of parts manufactured.

You can now appreciate the following four design categories:

(1) Failure of the part would endanger human life, or the part is made in extremely large quantities; consequently, an elaborate testing program is justified during design.

(2) The part is made in large enough quantities so that a moderate series of tests is feasible.

(3) The part is made in such small quantities that testing is not justified at all, or the design must be completed so rapidly that thert is not enough time for testing.

(4) The part has already been designed, manufacturde, and tested and found to be unsatisfactory. Analysis is required to understand why the part is unsatisfactory and what to do improce it.

It is with the last three categories that we shall be mostly concerned. This means that the designer will usually have only published values of yield strength, ultimate strength, and percentage elongation .With this meager information the engineer is expected to design against static and dynamic loads, biaxial and tri axial stress states,high and low temperatures, and large and small parts! The data usually available for design have been obtained from the simple tension test, where the load was applied gradually and the strain given time to develop. Yet these same must be was applied gradually and the strain given time to develop. Yet these same data must be used in designing parts with complicated dynamic loads applied thousands of times per minute. No wonder machine parts sometimes fail.

To sum up, the fundamental problem of the designer is to use the simple tension test data and relate them to the strength of the part, regardless of the stress state of the loading situation.

It is possible for two metals to have exactly the same strength and hardness, yet one of these metals may have a superior ability to absorb overloads, because of the property called ductility. Ductility is measured by the percentage elongation which occurs in the material at fracture. The usual dividing line between ductility and brittleness is 5 percent elongation. A material having less than 5 percent elongation at fracture is said to be brittle, while one having more is said to ductile. The elongaion of a material is usually measured over 50 mm gauge length. Since this is not a measure of the actual strain, another method of detemining ductility is sometimes used. After the specimen has been fractured, measurements are made of the area of the cross-sectional area. The characteristic of aductile material which permits ti to absorb large overloads ia an additional safety factor in design. Ductility is also important because it is a measure of that property of a material which permits it to be cole-worker. Such operations as bending and drawing are metal-processing operations which require ductile materials.

When a material is to be selected to tesistweat, erosion, or plastic deformation, hardness is generally the most important. Sevetal methods of hardness testing are available, depending upon which particular property is most desired. The four hardness numbers in greatest use are the Brinell, Rockwell, Vickers, and Koop. Most

hardness-testing systems employ a standard load which is applied to a ball or pyramid in contact with the material to be tested. The hardness is then expressed as a function of the size of the resulting indentation. This means that hardness is an easy property to measure, because the test is mondestructive and test specimens are not required Usually the test be conducted directly on an actual machine element.

Some Rules for Mechanical Design

Designing starts with a need, real or imagined. Existing apparatus may need improvements in durability, weight, speed, or cost. New apparatus may be needed toperform a function previously done by men, such as computation, assembly, or servicing. With the objecive wholly or partly defined, the next step in design is the conception of mechanisms and their arrangements that will perform the needed functions. For this, freehand sketching is of great value, not only as a record of one’s thoughts and as an aid in discussion with others,but particularly for communiaction with one’s own mind, as a stimulant for creative ideas.

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 perfromance, 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 strength 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 reacion forces and for the optimum utilization of friction; of dynamics for inertia, accelertion, and energy; of elasticity and stength of materials for stress and deflection; and of fluid mechanics for lubrication and hydrodynamic drives.

Finally, a design based upon funtion and reliability will be completed, and a prototype may be built. If its tests are satisfactory, and if the device is to be produced in quantity, 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 analysis based upon tests and experience indicate altertions. Sales appeal, customer satisfaction, and manufacture cost are all relaed to design, and ability in design is intimately involved in the success of an engineering venture.

To stimulate creative thought, the following rules are suggested for the

designer.

1、Apply ingenuity to utilize desired physical properties and to control undesired ones. The performance requirements of a machine are met by utilizing laws of nature or properties of matter(e.g, flexibility, strength, gravity, inertia, buoyancy, centrifugal force, principles of the lever and inclined plane, friction, viscosity, fluid pressure ,and thermal expansion), also the many electrical, optical, thermal, and chemical phenomena. However, what may be useful in one application may be detrimental in the next. Flexibility is desired in valve camshaft, friction is desired at the clutch face but not in the clutch bearing. Ingenuity in design should be applied to utilize and control the physical properties that are desired and to minimize those that are not desired.

2、Provide for favorable stress distribute and stiffness with minimum weight. On components subjected to fluctuating stress,particulat attention is given to a reduction in stress concentration, and to an increase of strength at fillets, threads, holes, and fits. Stress reduction are made by mondification in shape, and strengtening may be done by pre stressing treatments such as surface rolling and shallow hardening. Hollow shafts and tubing, and box sections give a facorable stress distribution, together with stiffness and minimum weigh. Sufficient stiffness to maintain alignment and uniform pressure between contacting surfaces should de provided for crank, cam, and gear shafts, and for enclosures and frames containing bearing supports. The stiffness of shafts and other components must be suitable to avoid resonant vibrations.

3、Use basic equations to calculate and optimize dimensions. The fundamental equations of mechanics and the other sciences are the accepted bases for calculations. They are sometimes rearranged in special forms to facilitate the determination or optimization of demensions, such as the beam and surtace stress equations for determining geat-tooth size. Factors may be added to a fundamental equation for conditions not analytically determinable, e.g, on thin steel tubes, an allowance forcorrosion added to the thickness based on pressure. When it is necessary to apply a fundamental equation to shapes, materials, or conditions which only approximate the assumptions for its derivation, it is done in a manner which gives results “ on the safe side” In situations where data are incomplete, equations of the sciences may be used as proportiong guides to extend a staifactory design to new capatities.

4、Choose materials for a conbination of properties. Materials should be chosen for a conbination of pertinent properties, not only for strengths, hardness, and weight,

but sometimes for resistance to impact, corrosion, and low or high temperatures. Cost and fabrication properties are factors, such as weld ability, machine ability, sensitivity to cariation in heat-treating temperatures, and required coating.

5、Select carefully between stock and integral components. A previously developed components is frequently selected by a designer and company from the stocks of parts manufacturers, if the component meet the performance and reliability requirements and is adaptable without additional development costs to the particular machine being designed. However, its selecion should be carefully made with a full knowledge of its properties, since the reputation and liability of the company suffer if there is a failure in any one of the machine’s parts, In other cases the strength, reliability, and cost requirements are better if the designer of the machine also designs thecomponent, with the particular advantage of compactness if it is designs the component, with the particular advantage of compactness if it is designs integral with other components, e.g, gears to be forged in clusters of integral with a shaft.

6、Provide for accurate location and non-interference of parts in assembly. A good design provides for the correct locating of parts and for easy assembly and repair. Shoulders and pilot surfaces give sccurate location without measurement during assembly. Shapes can be designed so that parts cannot be assembled backwards or in the wrong place. Interferences, as between screws in tapped holes, and between linkages must be foreseen and interference. Inaccurate alignment and positioning between detrimental displacements and stresses.

外文译文

机械零件强度

在设计任何机器或者结构时,所考虑的主要事项之一是其强度应该比它所承受的应力要大得多,以保证安全与可靠性。要保证机械零件在使用过程中不发生失效,就必须知道它们在某些时候会失效的原因,然后,才能应力与强度联系起来,以保证其安全。

设计任何机械零件的理想情况为:工程师可以利用大量的他所选择的这种材料的强度试验数据。这些试验应该采用与实际的零件有着相同的情况下进行。这表明,如果零件简要进行承受弯曲载荷,那么就应该进行弯曲载荷的试验。这些种类的试验可以提供非常有用和精度的数据。它们可以告诉工程师应该使用的安全系数和对于给定使用寿命时的可靠性。在设计中,只要能够获得这些数据,工程师就可以尽可能好地进行工程设计工作。如果零件的失效可能危害人的生命安全,或者零件有足够大的产量,则在设计前搜集的这些广泛的数据所花的费用是值得的。例如,汽车和冰箱的零件的产量非常大,可以在生产之前对它们进行的大量的试验,使用具有较高的可靠性。如果把进行这些试验的费用分摊到了所生产的零件上话,则分摊到所生产的每个零件上的费用非常低

你可以对下列四种类型的设计做出评价:

1、零件的失效可能危害人的生命安全,或者零件的产量非常的大,因此在设计时安排一个完善的试验程序会被认为是合理的。

2、零件的产量足够大,可以进行适当的系列试验。

3、零件的产量非常小,以至于进行试验根本不合算;或者要求很快地完成设计,以至于没有足够的时间进行试验。

4、零件已经完成设计、制造和试验,但结果不令人满意。这时需要采用分析的方法来弄清不能令人满意的原因和应该如何进行改进。

我们将主要对后三种类型进行讨论。这就是说,设计人员通常只能利用那些公开发表的屈服强度,极限强度和延伸率等数据资料。人们期望工程师利用这些不是很多的数据资料的基础上,对静载荷与动载荷,二维应力状态与三维应力状态,高温与低温以及大零件与小零件进行设计,而设计中所能利用的数据通常是从简单的拉伸试验中得到的,其载荷是逐渐加上去的,有充分的时间产生应变。到目前为止,还必须利用这些数据来设计每分钟承受几千次复杂的动载荷和作用的零件,因此机械零件有时会失效是不足为奇的。

概括的说,设计人员所遇到的基本问题是,不论对于哪一种应力状态或者载荷情况,都能利用简单的试验所获得的数据并将其零件的强度联系起来。可能会有两种情况具有完全相同的强度和硬度值的金属,其中一种由于本身的延展性而

具有很好的承受超载荷的能力。延展性与脆性的分界线。断裂时延伸率小于5%的材料称为脆性材料,大约5%的称为延性材料。材料的伸长量通常是在50mm的计量长度上测量的。因为这并不是对实际应变量的测量,所以有时也采用另一种测量延展性的方法。这个方法是在试件断裂后,测量其断裂处的横截面的面积。因此,延展性可以表示为横截面的收缩率。延性材料能够承受较大的超载荷这个特性,是设计中的附加安全因素。延性材料的重要性在于它是材料冷变形性能的衡量尺度。诸如弯曲和拉伸这种金属加工过程需要采用延性材料。

在选用抗磨损、抗腐蚀或者抗变形的材料时,硬度通常是最主要的性能。有几种可供选择的硬度试验反复法,采用哪一种方法取决于最希望测量的材料特性。最常用的四种硬度数值是步氏硬度、洛氏硬度、维氏硬度和努氏硬度。大多数硬度试验系统是将一个标准的载荷加在与被试验材料相接触的小球或者棱锥上。因此,硬度可以表示为所产生的压痕尺寸的函数。这表明由于硬度是非破坏性的试验,而且不需要专门的试件,因而,硬度是一个容易测量的性能。通常可以直接在实际的机械零件上进行硬度试验。

机械设计规则

设计是从实际或者假象的需要开始的,对于现有的设备可能需要在耐用性,效率进度成本等方面做进一步改进工作,也可能需要新的设备完成以前由人来做的工作,例如计算机或者装配。当目标完成或部分被确定以后,下一步设计步骤是对能够完成所需要的机构及其布局进行总体设计。对于此项工作,徒手画的草图是很有价值的,它不仅可以记录下我们的想法,而且还有助于与别人进行讨论,特别是和自己的大脑记性交流,从而促进创新想法的产生。

当一些零件的大致形状和几个尺寸被确定后,就可以开始认真的分析工作。分析工作的目的是要在重量最轻、成本最低的情况下,令人满意,即优良的工作性能,并且还要安全耐用。对于每个关键承载截面,应该寻求最佳的比例和尺寸,同时要对这几个零件的受力进行平衡。要对材料和处理方式进行选择。只有根据力学原理进行分析才能达到这些重要目的。这些分析包括根据静力学原理分析反作用力和充分利用摩擦力,根据动力学原理分析惯性、加速度和能量;根据弹性力学和材料力学分析应力和变形;根据流体力学来分析润滑和流体传动。

最后,完成基本功能要求和可靠性所进行的设计,且要制作一台样机。如果试验结果令人满意,而且该装置将要进行批量生产,就应该对最初提出的设计方案做出一些修改,是其能以比较低的成本进行批量生产。在以后的制造和使用期内,如果产生了新的想法或者根据试验和经验所做的进一步分析结果表明,可以有更好的替代方案,则很可能对原设计方案进行修改。销售吸引力、客户的满意

程度和制造成本均与设计有关,而设计能力则与工程创新是密切相关的。

为激发创造性思维,建议设计人员遵循下列准则:

1、创造性地利用所需要的物理性能和控制不需要的物理性能。可以利用自然法则或物理性能(例如柔性、强度、重力、惯性、浮力、离心力、杠杆原理和斜面原理、摩擦、粘性、流体压力和热膨胀)和许多电学、光学和化学现象来满足一台机器的设计要求。一种性能在某种场合下可能是有用的,而在另外一种场合下则可能是有害的。阀门的弹簧应该有柔性,而阀门的凸轮就不需要柔性。离合器结合面上需要有摩擦,而离合器轴承却不需要摩擦。设计时,需要创造性地利用和控制所要的物理性能,将不需要的物理性能减小至最小。

2、在重量最轻的情况下,提供合理的应里分布和刚度。对于承受交变应力的零件应该特别注意减轻应力集中和提高圆角,螺纹和配合处的强度。改变零件的形状,可以降低它所承受的应力,对零件施加预紧力,如表面滚压和浅表面硬化,均可使其得到强化。空心轴和空心管道,箱形截面能获得有利的应力分布,同时具有强度高而重量最轻的特点。曲轴,凸轮以及含有轴承支座的外壳和构架都具有足够的刚度以保证直线对中精度和接触表面之间的压力均匀分布。轴和其它零件须有适当的刚度,避免产生共振。

3、利用基本公式进行尺寸计算和尺寸优化。力学和其他学科的基本公式是公认的计算依据。有时需要见这些公式进行移项而化成特殊形式,以简化尺寸的计算或者对尺寸进行优化。例如,用梁的表面应力公式来计算齿轮的轮齿尺寸。在不能采用解析法计算的情况下,可以在基本公式内引入系数。例如,对于薄壁钢管,考虑到腐蚀性,可以根据压力求得的厚度增加一些。若必须应用一个基本公式来确定形状、材料和使用条件,而这些被确定的量值仅仅与在公式推导中的假设比较接近时,要采取措施使结果“偏于安全”。当数据不完全时,可以应用理论公式作为尺寸的指南,在扩展后的范围内获得令人满意的设计结果。

4、根据性能组合选择材料。选择材料时需要考虑强度,硬度和重量,而且有时还要考虑抗冲击性,抗腐蚀性和耐高温或低温的能力。成本和制造性能都是应该考虑的因素,这些因素包括可焊接性,机械加工性能,对热处理温度变化的敏感性和所需要的涂层性等

5、在现有的零件和整体零件之间进行认真的选择。若一个以前研制的零件能够满足要求和可靠性要求,并使用于所设计的那台机器而附加的研制费用,那么设计人员及其公司通常会从零件制造厂的现货中选取该零件。但是,只有充分了解其性能,才能进行认真的选择工作,因为任何一个机器零件的失效都会影响公司的信誉,并使公司承担相应的责任,在其他情况下,若机器设计人员自己来设计零件,则零件的强度,可靠性和成本等方面的要求就可以更好的得到满足。

可将某个零件与其他零件设计成一个整体零件,例如将几个齿轮设计为一体,这种方法的主要优点是紧凑。

6、保证零件在装配中准确定位和不发生干涉。一个良好的设计能够保证零件定位准确,装配和维修方便容易。轴肩和导向表面在装配过程中不需要测量就能够预见和防止诸如不同的螺纹孔中的螺钉之间干涉和不同的连杆机构之间的干涉。必须避免部件之间的校正对中定位误差,或者必须采用措施,减小任何由此引起的不利的位移和应力。

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

变速器论文中英文对照资料外文翻译文献

中英文对照外文翻译 汽车变速器设计 我们知道,汽车发动机在一定的转速下能够达到最好的状态,此时发出的功率比较大,燃油经济性也比较好。因此,我们希望发动机总是在最好的状态下工作。但是,汽车在使用的时候需要有不同的速度,这样就产生了矛盾。这个矛盾要通过变速器来解决。 汽车变速器的作用用一句话概括,就叫做变速变扭,即增速减扭或减速增扭。为什么减速可以增扭,而增速又要减扭呢?设发动机输出的功率不变,功率可以表示为 N = w T,其中w是转动的角速度,T 是扭距。当N固定的时候,w与T是成反比的。所以增速必减扭,减速必增扭。汽车变速器齿轮传动就根据变速变扭的原理,分成各个档位对应不同的传动比,以适应不同的运行状况。 一般的手动变速器内设置输入轴、中间轴和输出轴,又称三轴式,另外还有倒档轴。三轴式是变速器的主体结构,输入轴的转速也就是发动机的转速,输出轴转速则是中间轴与输出轴之间不同齿轮啮合所产生的转速。不同的齿轮啮合就有不同的传动比,也就有了不同的转速。例如郑州日产ZN6481W2G型SUV车手动变速器,它的传动比分别是:1档3.704:1;2档2.202:1;3档1.414:1;4档1:1;5档(超速档)0.802:1。 当汽车启动司机选择1档时,拨叉将1/2档同步器向后接合1档

齿轮并将它锁定输出轴上,动力经输入轴、中间轴和输出轴上的1档齿轮,1档齿轮带动输出轴,输出轴将动力传递到传动轴上(红色箭头)。典型1档变速齿轮传动比是3:1,也就是说输入轴转3圈,输出轴转1圈。 当汽车增速司机选择2档时,拨叉将1/2档同步器与1档分离后接合2档齿轮并锁定输出轴上,动力传递路线相似,所不同的是输出轴上的1档齿轮换成2档齿轮带动输出轴。典型2档变速齿轮传动比是2.2:1,输入轴转2.2圈,输出轴转1圈,比1档转速增加,扭矩降低。 当汽车加油增速司机选择3档时,拨叉使1/2档同步器回到空档位置,又使3/4档同步器移动直至将3档齿轮锁定在输出轴上,使动力可以从轴入轴—中间轴—输出轴上的3档变速齿轮,通过3档变速齿轮带动输出轴。典型3档传动比是1.7:1,输入轴转1.7圈,输出轴转1圈,是进一步的增速。 当汽车加油增速司机选择4档时,拨叉将3/4档同步器脱离3档齿轮直接与输入轴主动齿轮接合,动力直接从输入轴传递到输出轴,此时传动比1:1,即输出轴与输入轴转速一样。由于动力不经中间轴,又称直接档,该档传动比的传动效率最高。汽车多数运行时间都用直接档以达到最好的燃油经济性。 换档时要先进入空档,变速器处于空档时变速齿轮没有锁定在输出轴上,它们不能带动输出轴转动,没有动力输出。 一般汽车手动变速器传动比主要分上述1-4档,通常设计者首先确定最低(1档)与最高(4档)传动比后,中间各档传动比一

最全机械零件的强度.完整版.doc

第一篇总论 第三章机械零件的强度 3-1 某材料的对称循环弯曲疲劳极限σ-1=180MPa,取循环基数N0=5?106,m=9,试求循环次数N分别为7000,2500,620000次是时的有限寿命弯曲疲劳极限。 3-2 已知材料的力学性能为σS=260MPa,σ-1=170MPa,ψσ=0.2,试绘制此材料的简化极限应力线图(参看图3-3中的A’D’G’C)。 3-3 一圆轴的轴肩尺寸为:D=72mm,d=62mm,r=3mm。材料为40CrNi,其强度极限σB=900MPa,屈服极限σS=750MPa,试计算轴肩的弯曲有效应力集中系数kσ。 3-4 圆轴轴肩处的尺寸为:D=54mm,d=45mm,r=3mm。如用题3-2中的材料,设其强度极限σB=420MPa,试绘制此零件的简化极限应力线图。 3-5 如题3-4中危险截面上的平均应力σm=20MPa,应力幅σa=900MPa,试分别按:a)r=C;b)σm=C,求出该截面的计算安全系数S ca。 第二篇联接 第五章螺纹联接和螺旋传动 5-1 分析比较普通螺纹、管螺纹、梯形螺纹和锯齿形螺纹的特点,各举一例说明它们的应用。5-2 将承受轴向变载荷的联接螺栓的光杆部分做得细些有什么好处? 5-3 分析活塞式空气压缩机气缸盖联接螺栓在工作时的受力变化情况,它的最大应力,最小应力如何得出?当气缸内的最高压力提高时,它的最大应力、最小应力将如何变化? 5-4 图5-49所示的底板螺栓组联接受外力F∑的作用。外力F∑作用在包含x轴并垂直于底板接合面的平面内。试分析底板螺栓组的受力情况,并判断哪个螺栓受力最大?保证联接安全工作的必要条件有哪些? 5-5 图5-50是由两块边板和一块承重板焊成的龙门起重机导轨托架。两块边板各用4个螺栓与立柱相联接,托架所承受的最大载荷为20kN,载荷有较大的变动。试问:此螺栓联接采用普通螺栓联接还是铰制孔用螺栓联接为宜?为什么? 5-6 已知一个托架的边板用6个螺栓与相邻的机架相联接。托架受一与边板螺栓组的垂直对称轴线相平行、距离为250mm、大小为60kN的载荷作用。现有如图5-51所示的两种螺栓布置型式,设采用铰制孔用螺栓联接,试问哪一种布置型式所用的螺栓直径较小?为什么?

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。

外文文献翻译:汽车的发展

The development of automobile As the world energy crisis and the war and the energy consumption of oil -- and are full of energy in one day someday it will disappear without a trace. Oil is not inresources. So in oil consumption must be clean before finding a replacement. With the development of science and technology the progress of the society people invented the electric car. Electric cars will become the most ideal of transportation. In the development of world each aspect is fruitful especially with the automobile electronic technology and computer and rapid development of the information age. The electronic control technology in the car on a wide range of applications the application of the electronic device cars and electronic technology not only to improve and enhance the quality and the traditional automobile electrical performance but also improve the automobile fuel economy performance reliability and emission spurification. Widely used in automobile electronic products not only reduces the cost and reduce the complexity of the maintenance. From the fuel injection engine ignition devices air control and emission control and fault diagnosis to the body auxiliary devices are generally used in electronic control technology auto development mainly electromechanical integration. Widely used in automotive electronic control ignition system mainly electronic control fuel injection system electronic control ignition system electronic control automatic transmission electronic control ABS/ASR control system electronic control suspension system electronic control power steering system vehicle dynamic control system the airbag systems active belt system electronic control system and the automatic air-conditioning and GPS navigation system etc. With the system response the use function of quick car high reliability guarantees of engine power and reduce fuel consumption and emission regulations meet standards. The car is essential to modern traffic tools. And electric cars bring us infinite joy will give us the physical and mental relaxation. Take for example automatic transmission in road can not on the clutch can achieve automatic shift and engine flameout not so effective improve the driving convenience lighten the fatigue strength. Automatic transmission consists mainly of hydraulic torque converter gear transmission pump hydraulic control system electronic control system and oil cooling system etc. The electronic control of suspension is mainly used to cushion the impact of the body and the road to reduce vibration that car getting smooth-going and stability. When the vehicle in the car when the road uneven road can according to automatically adjust the height. When the car ratio of height low set to gas or oil cylinder filling or oil. If is opposite gas or diarrhea. To ensure and improve the level of driving cars driving stability. Variable force power steering system can significantly change the driver for the work efficiency and the state so widely used in electric cars. VDC to vehicle performance has important function it can according to the need of active braking to change the wheels of the car car motions of state and optimum control performance and increased automobile adhesion controlling and stability. Besides these appear beyond 4WS 4WD electric cars can greatly improve the performance of the value and ascending simultaneously. ABS braking distance is reduced and can keep turning skills effectively improve the stability of the directions simultaneously reduce tyre wear. The airbag appear in large programs protected the driver and passengers safety and greatly reduce automobile in collision of drivers and passengers in the buffer to protect the safety of life. Intelligent electronic technology in the bus to promote safe driving and that the other functions. The realization of automatic driving through various sensors. Except some smart cars equipped with multiple outside sensors can fully perception of information and traffic facilities

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

变速器设计,中英文带翻译

原文: Transmission design As we all know automobile engine to a certain speed can be achieved under the best conditions, when compared issued by the power, fuel economy is relatively good. Therefore, we hope that the engine is always in the best of conditions to work under. However, the use of motor vehicles need to have different speeds, thus creating a conflict. Transmission through this conflict to resolve. Automotive Transmission role sum up in one sentence, called variable speed twisting, twisting or slow down the growth rate by increasing torsional. Why can slow down by twisting, and the growth rate but also by twisting? For the same engine power output, power can be expressed as N = WT, where w is the angular velocity of rotation. When N fixed, w and T is inversely proportional to the. Therefore, the growth rate will reduce twisting, twisting slowdown will increase. Automotive Transmission speed gear based on the principle of variable twisted into various stalls of different transmission ratio corresponding to adapt to different operational conditions. General to set up a manual gearbox input shaft, intermediate shaft and output shaft, also known as the three-axis, as well as Daodang axis. Three-axis is the main transmission structure, input shaft speed is the speed of the engine, the output shaft speed is the intermediate shaft and output shaft gear meshing between different from the speed. Different gears are different transmission ratio, and will have a different speed. For example Zhengzhou richan ZN6481W2G manual transmission car-SUV, its transmission ratio are: 1 File 3.704:1; stalls 2.202:1; stalls 1.414:1; stalls 1:1 5 stalls (speeding file) 0.802: 1. When drivers choose a launch vehicle stalls, Plectrum will be 1 / 2 file synchronization engagement with a back stall gear and output shaft lock it, the power input shaft, intermediate shaft and output shaft gear of a stall, a stall the output shaft gear driven, and the output shaft power will be transmitted to the drive shaft (red arrow). A typical stall Biansuchilun transmission ratio is 3:1, that is to say three laps

浅谈机械零件的强度(

第三章 机械零件的强度 § 3 – 1 材料的疲劳特性 一、交变应力的描述 静应力,变应力 max ─最大应力; min ─最小应力 m ─平均应力; a ─应力幅值 2 min max σσσ+= m 2 min max σσσ-= a max min σσ= r r ─应力比(循环特性)

【注意】 1)已知任意两个参数,可确定其他三个参数。一般已知 max,r; 2) max, min指代数值; a为绝对值; 3)-1≤r ≤ +1; a=0,r =+1,为静应力 r = -1 对称循环应力r=0 脉动循环应力r=1静应力 二、疲劳曲线(σ-N曲线) 1.材料的疲劳极限:σr N 在一定应力比为г的循环变应力作用下,应力循环N 次后,材料不发生疲劳破坏时,所能承受的最大应力σmax。 2.疲劳寿命:N 材料疲劳失效前所经历的应力循环次数。

σ-N疲劳曲线 г不同或N不同时,疲劳极限σrN不同。即σrN与r、N 有关。疲劳强度计算中,就是以疲劳极限作为σlim。 即σlim=σrN。通过实验可得,疲劳极限σrN与循环次数N之间关系的曲线,如上图所示。 AB段曲线:N<103,计算零件强度时按静强度计算。(σrN≈σs) BC段曲线:103

N D 与材料有关,有的相差很大,因此规定一个常数。 N 0?循环基数 当N >N D 时,σrN =σr ∞=σr (简记) 疲劳曲线以N 0为界分为两个区: 1)有限寿命区 把曲线CD 段上的疲劳极限σr 称为有限疲劳极限(条件~)。 当材料受到的工作应力超过σr 时,在疲劳破坏之前,只能经受有限次的应力循环。即寿命是有限的。 【说明】 不同应力比г时的疲劳曲线具有相似的形状。但г↑,σrN ↑。 2)无限寿命区 当N >N 0时,曲线为水平直线,对应的疲劳极限是一个定值,——称为持久疲劳极限,用0rN σ表示 (简写为σr )。在工程设计中,一般认为:当材料受到的应力不超过σr 时,则可以经受无限次的循环应力而不疲劳破坏——即寿命是

机械图纸中英文翻译汇总

近几年,我厂和英国、西班牙的几个公司有业务往来,外商传真发来的图纸都是英文标注,平时阅看有一定的困难。下面把我们积累的几点看英文图纸的经验与同行们交流。 1标题栏 英文工程图纸的右下边是标题栏(相当于我们的标题栏和部分技术要求),其中有图纸名称(TILE)、设计者(DRAWN)、审查者(CHECKED)、材料(MATERIAL)、日期(DATE)、比例(SCALE)、热处理(HEAT TREATMENT)和其它一些要求,如: 1)TOLERANCES UNLESS OTHERWISE SPECIFIAL 未注公差。 2)DIMS IN mm UNLESS STATED 如不做特殊要求以毫米为单位。 3)ANGULAR TOLERANCE±1°角度公差±1°。 4)DIMS TOLERANCE±0.1未注尺寸公差±0.1。 5)SURFACE FINISH 3.2 UNLESS STATED未注粗糙度3.2。 2常见尺寸的标注及要求 2.1孔(HOLE)如: (1)毛坯孔:3"DIAO+1CORE 芯子3"0+1; (2)加工孔:1"DIA1"; (3)锪孔:锪孔(注C'BORE=COUNTER BORE锪底面孔); (4)铰孔:1"/4 DIA REAM铰孔1"/4; (5)螺纹孔的标注一般要表示出螺纹的直径,每英寸牙数(螺矩)、螺纹种类、精度等级、钻深、攻深,方向等。如: 例1.6 HOLES EQUI-SPACED ON 5"DIA (6孔均布在5圆周上(EQUI-SPACED=EQUALLY SPACED均布) DRILL 1"DIATHRO' 钻1"通孔(THRO'=THROUGH通) C/SINK22×6DEEP 沉孔22×6 例2.TAP7"/8-14UNF-3BTHRO' 攻统一标准细牙螺纹,每英寸14牙,精度等级3B级 (注UNF=UNIFIED FINE THREAD美国标准细牙螺纹) 1"DRILL 1"/4-20 UNC-3 THD7"/8 DEEP 4HOLES NOT BREAK THRO钻 1"孔,攻1"/4美国粗牙螺纹,每英寸20牙,攻深7"/8,4孔不准钻通(UNC=UCIFIED COARSE THREAD 美国标准粗牙螺纹)

机械零件的强度

机械零件的强度 Document number【AA80KGB-AA98YT-AAT8CB-2A6UT-A18GG】

沈阳工业大学备课用纸 第三章机械零件的强度 1.强度问题: 静应力强度:通常认为在机械零件整个工作寿命期间应力变化次数小于103的通用零件,均按静应力强度进行设计。 (材料力学范畴) 变应力强度:在变应力作用下,零件产生疲劳破坏。 2.疲劳破坏定义:金属材料试件在交变应力作用下,经过长时间的试 验而发生的破坏。 3.疲劳破坏的原因:材料内部的缺陷、加工过程中的刀痕或零件局部 的应力集中等导致产生了微观裂纹,称为裂纹源,在交变应力作用下,随着循环次数的增加,裂纹不断扩展,直至零件发生突然断裂。4.疲劳破坏的特征: 1)零件的最大应力在远小于静应力的强度极限时,就可能发生破坏; 2)即使是塑性材料,在没有明显的塑性变形下就可能发生突然的脆性断裂。 3)疲劳破坏是一个损伤累积的过程,有发展的过程,需要时间。 4) 疲劳断口分为两个区:疲劳区和脆性断裂区。 §3-1 材料的疲劳特性 一、应力的分类 1、静应力:大小和方向均不随时间改变,或者变化缓慢。 2、变应力:大小或方向随时间而变化。 1)稳定循环变应力: 以下各参数不随时间变化的变应力。 ?m─平均应力; ?a─应力幅值 ?max─最大应力; ?min─最小应力r ─应力比(循环特性) 描述规律性的交变应力可有5个参数, 但其中只有两个参数是独立的。 沈阳工业大学备课用纸 r = -1 对称循环 应力 r=0 脉动循环应 力 r=1 静应力

2)非稳定循环变应力: 参数随时间变化的变应力。 (1)规律性非稳定变应力:参数按一定规律周期性变化的称为。 (2)随机变应力:随机变化的。 二、疲劳曲线 1、σ-N 曲线:应力比r 一定时,表示疲劳极限N γσ(最大应力)与 循环次数N 之间关系的曲线。典型的疲劳曲线如下图示: 大多数零件失效在C 点右侧区域,称高周疲劳区N>104 高周疲劳区以N 0为界分为两个区: 有限寿命区(CD): N <N 0,循环次数N,对应的极限应力 N γσ 。 N γσ ——条件疲劳极限。 曲线方程为 m N N C γσ?= 曲线可分为AB BC CD D 右 四个区域。 其中: AB 区最大应力变化不大,可按静应力考虑。 BC:为低周疲劳(循环次数少) 区。N<104 。也称应变疲劳(疲劳破坏伴随塑性变形) M-材料常数 N 0-循环基数 沈阳工业大学备课用纸 ?-N 疲劳曲线

汽车变速器设计外文翻译

汽车变速器设计 ----------外文翻译 我们知道,汽车发动机在一定的转速下能够达到最好的状态,此时发出的功率比较大,燃油经济性也比较好。因此,我们希望发动机总是在最好的状态下工作。但是,汽车在使用的时候需要有不同的速度,这样就产生了矛盾。这个矛盾要通过变速器来解决。 汽车变速器的作用用一句话概括,就叫做变速变扭,即增速减扭或减速增扭。为什么减速可以增扭,而增速又要减扭呢?设发动机输出的功率不变,功率可以表示为 N = w T,其中w是转动的角速度,T是扭距。当N固定的时候,w与T是成反比的。所以增速必减扭,减速必增扭。汽车变速器齿轮传动就根据变速变扭的原理,分成各个档位对应不同的传动比,以适应不同的运行状况。 一般的手动变速器内设置输入轴、中间轴和输出轴,又称三轴式,另外还有倒档轴。三轴式是变速器的主体结构,输入轴的转速也就是发动机的转速,输出轴转速则是中间轴与输出轴之间不同齿轮啮合所产生的转速。不同的齿轮啮合就有不同的传动比,也就有了不同的转速。例如郑州日产ZN6481W2G型SUV车手动变速器,它的传动比分别是:1档3.704:1;2档2.202:1;3档1.414:1;4档1:1;5档(超速档)0.802:1。 当汽车启动司机选择1档时,拨叉将1/2档同步器向后接合1档齿轮并将它锁定输出轴上,动力经输入轴、中间轴和输出轴上的1档齿轮,1档齿轮带动输出轴,输出轴将动力传递到传动轴上(红色箭头)。典型1档变速齿轮传动比是3:1,也就是说输入轴转3圈,输出轴转1圈。 当汽车增速司机选择2档时,拨叉将1/2档同步器与1档分离后接合2档齿轮并锁定输出轴上,动力传递路线相似,所不同的是输出轴上的1档齿轮换成2档齿轮带动输出轴。典型2档变速齿轮传动比是2.2:1,输入轴转2.2圈,输出轴转1圈,比1档转速增加,扭矩降低。

汽车变速器外文翻译

外文翻译 Auto Transmission First, an overview of automotive transmission and the development trend Automobile available more than a century, especially from the mass production of motor vehicles and the automotive industry since the development of large, Car has been the economic development of the world for mankind to enter the modern life and have had a tremendous impact on the immeasurable, The progress of human society has made indelible contributions to the great, epoch-making set off arevolution. From From the vehicle as a power plant using internal combustion engine to start, auto transmission has become an important component. Is Generation is widely used in automotive reciprocating piston internal combustion engine with a small size, light weight, reliable operation and the use of The advantages of convenience, but its torque and speed range of smaller changes, and complex condition requires the use of motor vehicles Traction and the speed can be considerable changes in the scope. Therefore, its performance and vehicle dynamics and economy of There are large inter-contradictions, which contradictions of modern automotive internal combustion engine by itself is insoluble. Because Here, in the automotive power train set up the transmission and main reducer in order to achieve the purpose of deceleration by moment. Speed The main function of performance: ⑴ change gear ratio of motor vehicles, and expand the wheel drive torque and rotational speed of the Fan Wai, in order to adapt to constantly changing driving cycle, while the engine in the most favorable conditions within the scope of work; ⑵no change in the direction of engine rotation, under the premise of the realization of cars driving back; ⑶the realization of the free, temporary Interruption of power transmission, in order to be able to start the engine, idling, etc.. V ariable-speed drive transmission by the manipulation of institutions and agencies. Change the transmission ratio by way of transmission is divided into There are class-type, non-stage and multi-purpose three. Have class most widely used transmission. It uses gear drive, with a number of transmission ratio setting. Stepless transmission Continuously V ariable Transmission (CVT) transmission ratio of a certain The framework of multi-level changes may be unlimited, there is a common type of power and torque (dynamic fluid-type) and so on. Continuously V ariable Transmission Transmission development is the ultimate goal, because only it can make the most economical engine in working condition Can provide the best vehicle fuel economy and optimal power in order to provide the most comfortable By the feeling. Today's CVT is a typical representative of the CVT

机械设计机械零件的强度

第三章 机械零件的强度 §3T 材料的疲劳特性 、交变应力的描述 静应力,变应力 max ——最大应力; 平均应力; max r ——应力比(循环特性) 【注意】 1) 已知任意两个参数,可确定其他三个参数。一般已 max , r ; 2) max , min 指代数值;a 为绝对值; 3) -1 r + 1 ; a =0, r =+1 ,为静应力 min max min 2

r = -1对称循环应力

疲劳曲线(-N 曲线) 1.材料的疲劳极限:r N 在一定应力比为 r 的循环变应力作用下,应力循环 N 次后,材料不发生疲劳破坏时,所能承受的最大应力 max 。 2.疲劳寿命:N 材料疲劳失效前所经历的应力循环次数。 有关。疲劳强度计算中,就是以疲劳极限作为 lim 即lim = rN 。通过试验可得,疲劳极限 rN 与循环次数N 之 间关系的曲线,如上图所示 6 ( 6 A B \ /T 、 1 r 不同或N 不同时,疲劳极限rN 不同 。即rN 与r 、N —N 疲劳曲线

AB段曲线:N 103,计算零件强度时按静强度计算。 (rN s) BC段曲线:103N 104,零件的破坏为塑性破坏属于低周疲劳破坏。特点:应力高,寿命低。 CD段曲线:r N随N的增大而降低。但是当N超过某一次数时(图中N D),曲线趋于水平。即r N不再减小。 N D与材料有关,有的相差很大,因此规定一个常数。 当N N D时,rN= r = r (简记) 疲劳曲线以N o为界分为两个区: 1)有限寿命区 把曲线CD段上的疲劳极限r称为有限疲劳极限(条件?)。当材料受到的工作应力超过r时,在疲劳破坏之前,只能经受有限次的应力循环。即寿命是有限的。 【说明】

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形状和详细结构的基本主要研究产品的尺寸、学。它涉及工程技术的各个领域,构思,还要研究产品在制造、销售和使用等方面的问题。机械设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。还必须在机械制设计工程师不仅在工作上要有创造性,计是一项创造性的工作。材料力学和机械制造工艺学等方面具有深厚的基础知识。工程材料、图、运动学、发现和科技机械设计的目的是生产能够满足人类需求的产品。发明、如前所诉,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必须先确定人们是否需因而,应该认识到在一个特定的产品进行设计之前,益。要这种产品。系统分析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、掌握工程基础知识要比熟记一些数据和公和制定产品的制造工艺学的一个良机。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式更为重要。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。当新的方而且愿意承担一定的风险,一个好的设计人员应该勇于提出新的想法,所花费法不适用时,就使用原来的方法。因此,设计人员必须要有耐心,因为为要求屏弃许多陈旧的,的时间和努力并不能保证带来成功。一个全新的设计,一位机由于许多人墨守成规,这样做并不是一件容易的事。人们所熟知的方法。在此过程中应该认真选择原有械设计师应该不断地探索改进现有的产品的方法,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。只有当这些缺陷和问题被解决新设计本身会有许多缺陷和未能预料的问题发生,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,也就没如果设计本身不要求采用全新的方法,伴随着较高的风险。应该强调的是,有必要仅仅为了变革的目的而采用新方法。即使产不受各种约束。应该允许设计人员充分发挥创造性,在设计的初始阶段,只有也会在设计的早期,生了许多不切实际的想法,即绘制图纸之前被改正掉。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。 .. . 设计人员的基本职责是努心理学家经常谈论如何使人们适应他们所操作的机器。因为实际上并不存在着一个对力使机器来适应人们。这并不是一项容易的工作,所有人来说都是最优的操作范围和操作过程。在开始另一个重要问题,设计工程师必须能够同其他有关人员进行交流和磋商。这一并得到批准。阶段,设计人员必须就初步设计同管理人员进行交流和磋商,,需要解决般是通过口头讨论,草图和文字材料进行的。为了进行有效的交流下列问题:)所设计的这个产品

相关文档