西工大机电专业英语翻译

Text 1 Phases of Aircraft Design

Conceptual Design

Aircraft design can be broken into three major phases, Conceptual Design, Preliminary Design and Detail Design. Conceptual design is the primary focus of this book. It is in conceptual design that the basic questions of configuration arrangement, size and weight, and performance are answered.

The first question is, “Can an affordable aircraft be built that meets the requirements?” If not, the customer may wish to relax the requirement.

Conceptual design is a very fluid process. New ideas and problems emerge as a design is investigated in ever-increasing detail. Each time the latest design is analyzed and sized, it must be redrawn to reflect the new gross weight, fuel weight, wing size, engine size, and other changes. Early wing-tunnel tests often reveal problems requiring some changes to the configuration. The steps of conceptual design are described later in more detail.

飞机设计可以分成三个主要的阶段：概念设计、初步设计和详细设计。本书主要讨论概念设计。飞机外形，尺寸和重量以及性能等基本问题在概念设计阶段都将得到答案。

第一个问题是：“能否生产出经济上可以承受，性能上满足要求的飞机？”如果答案是否定的，那么订购商应该考虑放宽要求。

概念设计是一个灵活多变的过程。新的想法和新的问题都会随着设计的进一步细化而出现。每一次最新的设计经过分析和定尺寸后，都要重新绘制草图以体现出新的总重，油料重量，机翼尺寸，发动机尺寸和其它变化。早期的风动测试通常会反应出很多的问题，需要对飞机的外形进行改进。我们将在后面更加详细的讨论概念设计的步骤。

Preliminary Design

Preliminary design can be said to begin when the major changes are over. The big questions such as whether to use a canard or an aft tail have been resolved. The configuration arrangement can be expected to remain about as shown on current drawings, although minor revisions may occur. At some point late in preliminary design, even minor changes are stopped when a decision is made to freeze the configuration.

During preliminary design the specialists in areas such as structures, landing gear, and control systems will design and analyze their portion of the aircraft. Testing is initiated in areas such as aerodynamics, propulsion, structures, and stability and control. A mockup may be constructed at this point.

初步设计可以说在主要的改进结束后就开始了。像要采用鸭翼还是尾翼等的重要问题已经被确定下来了。虽然会有小的修改，但飞机的外形布局仍然希望以现有设计图纸主。在初步设计后期的某个时候，当飞机外形布局被确定的时候，即使很小的修改也是不允许的。

在初步设计阶段，来自不同领域的专家，如结构、起落架和控制系统等，将设计和分析飞机上与他们相关的那一部分。气动、推力、结构、稳定性和控制测试就开始了。样机可能会在这一阶段建造出来。

A key activity during preliminary design is “lofting”. Lofting is the mathematical modeling of the outside skin of the aircraft with sufficient accuracy to insure proper fit between its different parts, even if they are designed by different designers and possibly fabricated in different

locations. Lofting originated in shipyards and was originally done with long flexible rulers called “splines”. This work was done in a loft over the shipyard; hence the name.

The ultimate objective during preliminary design is to ready the company for the detail design stage, also called full-scale development. Thus, the end of preliminary design usually involves a full-scale development proposal. In today’s environment, this can result in a situation jokingly referred to as “you-bet-your-company”. The possible loss on an overrun contract or from lack of scales can exceed the net worth of the company! Preliminary design must establish confidence that the airplane can be built on time and at the estimated cost.

初步设计阶段一个重要的活动就是放样。放样就是有足够的准确度的飞机蒙皮外形的数字化模型，它用来保证飞机不同部分之间能够很好的配合，即使这些组件或配件来自不同的设计部门，或者由不同的工厂生产。放样源于船坞，最初是用一根被称为样条的长软尺来完成的。这项工作是在船坞上面的阁楼中完成的，因此就获到了这个名字。

初步设计阶段的目标是让企业为详细设计，或者是说零件设计阶段做好准备。因此，初步设计通常会给出一个完整规模发展的计划书。在现在的环境下，这将陷进这样的一个被戏称为“你将赌注压在你公司身上”这样的一个情形中。合同上的超支或缺乏衡量尺度引起的损失会超过公司的净产值。初步设计必须相信飞机制造能按预期费用并准时完工。

Detail Design

Assuming a favorable decision for entering full-scale development, the detail design phase begins in which the actual pieces to be fabricated are designed. For example, during conceptual and preliminary design the wing box will be designed and analyzed as a whole. During detail design, that whole will be broken down into individual ribs, spars, and skins, each of which must be separately designed and analyzed.

Another important part of detail design is called production design. Specialists determine how the airplane will be fabricated, starting with the smallest and simplest subassemblies and building up to the final assembly process. Production designers frequently wish to modify the design for ease of manufacture; that can have a major impact on performance or weight. Compromises are inevitable, but the design must still meet the original requirements.

当支持做出进入大量生产的决定的时候，详细设计阶段就开始了。在详细设计阶段，每一个将要加工生产的具体零件都会被设计出来。例如，在概念设计和初步设计阶段翼盒是作为一个整体设计和分析的。在详细设计阶段，翼盒将分成独立的翼肋、桁条和蒙皮，并分别进行设计和分析。

详细设计另一个重要的部分是生产设计。专业人员决定如何去制造飞机，从最小最简单的组件开始，然后在最后的总装配中进行组装。生产设计人员会经常想改变一些设计以达到简化制造，但这些改变会对飞机性能和重量都有很大的影响。难免要进行协调工作，但设计必须满足最初的设计要求。

It is interesting to note that in the Soviet Union, the production design is done by a completely different design bureau than conceptual and preliminary design, resulting in superior producibility at some expense in performance and weight.

During detail design, the testing effort intensifies. Actual structure of the aircraft is fabricated and tested. Control laws for the flight control system are tested on an “iron-bird” simulator, a detailed working model of the actuators and flight control surfaces. Flight simulators are developed and flown by both company and customer test-pilots.

Detail design ends with fabrication of the aircraft. Frequently the fabrication begins on part of the aircraft before the entire detail-design effort is completed. Hopefully, changes to already-fabricated pieces can be avoided.

The further along a design progresses, the more people are involved. In fact, most of the engineers who go to work for a major aerospace company will work in preliminary or detail design.

很有趣的是在前苏联，生产设计是由一个完全不同的部门来完成，而不是原来的概念设计和初步设计部门。这样造成了飞机在牺牲了部分性能和增加重量的代价下换来了高的生产率。

在详细设计阶段加强了测试工作。实际的飞机结构被制造出来并进行测试。飞行控制系统的控制指令在一个叫做铁鸟的模拟器上进行测试。铁鸟是控制器和飞行控制面的一个详细的工作模型。飞行模拟器开发出来，并用于企业和订购方试飞员的试飞。

飞机开始制造的时候详细设计也就结束了。通常在详细设计工作没有完全完成之前，飞机部分零件的生产制造就已经开始了。我们希望避免那些已经生产的部件再进行更改。

设计过程走的越远，涉及的人员就越多。实际上，大部分在飞机工厂上班的工程师都是在初始设计或详细设计阶段工作的。

Text 2 Aircraft conceptual design

Figure 2.1depicts the conceptual design process in greater detail. Conceptual design will usually begin either a specific set of design requirements established by the prospective customer or company-generated guess as to what future customers may need. Design requirements include parameters such as the aircraft range and payload, takeoff and landing distance, and maneuverability and speed requirements.

The design requirements also include a vast set if civil or military design specifications which must be met. These include landing sink-speed , stall speed , structural design limits, pilots’ outside vision angles, reserve fuel, and many others.

图2.1更详细的反应了概念设计的过程。概念设计通常是根据将来用户需求提出一套明确的设计需求开始，或由公司推测潜在用户的需求而产生的。设计需求包含了相关的参数，像飞机的航程和有效载荷、起飞和着陆距离、操作性能和速度要求。

设计要求中还包含了大量的民用或者军用设计标准，这些要求都必须满足。这些包括飞机降落下沉速度，失速速度，设计结构强度，飞行员外视角和储油量等。

Sometimes a design will begin as an innovative idea rather than as a response to a given requirement. The flying wings pioneered by John Northrop were not conceived in response to a specific Army Air Corps requirement at that time, but instead were the product of one man’s idea of the “better airplane”. Northrop pursued this idea for years before building a flying wing to suit a particular military requirement.

Before a design can be started, a decision must be made as to what technologies will be incorporated. If a design is to be built in the near future, it must use only currently-available technologies as well as existing engines and avionics . If it is being designed to be built in the more distant future, then an estimate of the technologies will be ready for use at that time.

有时候设计开始于一个创新的设想而不是对某个特定需求的回应。John Northrop 研发飞翼的时候并不是出于满足空军某些要求，而是出于一个人对更好的飞机的一个构想。

Northrop 用了几年的时间完成这个构想，最终满足了军方的一些特定的要求。

在设计开始之前必须决定要用到什么技术。如果一个设计要在近期制造出来，那么它只能用到目前可用的技术，包括现有的发动机和航空电子设备。如果一个设计要在将来才制造出来，那么就要估计到那个时候可用的技术有哪些。

For example, an all-composite fighter has not yet to enter high-rate production as of this date (1989), but can confidently be predicted by 1999. On the other hand, active laminar flow control by suction pumps shows great payoff analytically, but would be considered by many to be too risky to incorporate into a new transport jet in the near future.

An optimistic estimate of the technology availability will yield a lighter, cheaper aircraft to perform a given mission, but will also result in a higher development risk.

The actual design effort usually begins with a conceptual sketch (Fig.2.4). This is the “back of a napkin” drawing of aerospace legend, and gives a rough indication of what the design may look like. A good conceptual sketch will include the approximate wing and tail geometries, the fuselage shape, and the internal locations of the major components such as the engine, cockpit, payload/ passenger compartment, landing gear, and perhaps the fuel tanks.

例如，全复合材料的战斗机在1989年的时候不会进入大量生产阶段，但是可以乐观的预测到1999年这一技术可以实现。从另一方面讲，用吸气泵控制的活跃层流控制技术分析显示具有很大的经济性，但是很多人都会认为在不远的将来将这一技术集成到新的航空运输机中是具有很大的风险。

对技术发展的乐观估计会催生更轻的，更廉价的飞机来完成指定的任务，但也会带来更大的风险。

实际的设计工作通常开始于一个概念草图（如图2.4）. 这是一个“餐巾纸背面草图”式的航空神话（这是一个飞机原理草图），它估计出了一个飞机设计大概的样子。一个好的设计草图应该包括飞机近似的机翼和尾翼的几何形状，机身的形状，还有像发动机、座舱、客舱/包厢，起落架或者燃料箱等主要部件的布局。

The conceptual sketch can be used to estimate aerodynamics and weight fractions by comparison to previous designs. These estimates are used to make a first estimate of the required total weight and fuel weight to perform the design mission, by a process called “sizing”. The conceptual sketch may not be needed for initial sizing if the design resembles previous ones. The “first-order ” sizing provides the information needed to develop an initial design layout (Fig.2.5). This is a three-view drawing complete with the more important internal arrangement details, including typically the landing gear, payload or passenger compartment, engines and inlet ducts, fuel tanks, cockpit, major avionics, and any internal components which are large enough to affect the overall shaping of the aircraft. Enough cross-sections are shown to verify that everything fits.

通过与以前的设计进行比较概念设计草图可以用来估计空气动力学和重量比率。这些估计通过一个叫做“定尺寸”的过程来初步估计按要求的总重和燃料重量完成设计任务。如果设计和之前的设计类似，那么概念草图也可能不会用到最初所定的尺寸。

初步的定尺寸为开发出最初的设计布局提供了必要的信息如图2.5。这是一个包含了更重要的内部布局细节的三维图。通常包括了起落架、有效载荷或者是客舱/包厢，发动机和进气口，燃料箱，座舱，主要的航空电子设备以及所有较大的可以影响到飞机的整体外形的内部部件。显示了足够多的横截面来证明所有的配合合适。

On a drafting table, the three-view layout is done in some convenient scale such as 1/10, 1/20, 1/40, or 1/100(depending upon the size of the airplane and the available paper). On a

computer-aided design system, the design work is usually done in full scale (numerically).

This initial layout is analyzed to determine if it really will perform the mission as indicated by the first-order sizing. Actual aerodynamics, weights, and installed propulsion characteristics are analyzed and subsequently used to do a detailed sizing calculation. Furthermore, the performance capabilities of the design are calculated and compared to the requirements mentioned above. Optimization techniques are used to find the lightest or lowest-cost aircraft that will both perform the design mission and meet all performance requirements.

优化技术

在绘图板上，三维的布局通常是用合适的比例来表示的，像1/10, 1/20, 1/40, 或者 1/100（这取决于飞机的尺寸大小和纸张的大小）。在计算机辅助设计系统中，设计工作通常是按全尺寸来完成的（数字的）。

最初的布局要经过分析，以确定它是否真的可以完成初步定尺寸所指出的任务。实际的空气动力性能，重量，安装的推力性能也要经过分析并随后用来进行详细的尺寸计算。而且设计的性能被计算出来并与上面提到的要求对比。优化技术用来发现能够完成设计需求并且满足所有性能要求的最轻，最廉价的飞机。

The results of this optimization include a better estimate of the required total weight and fuel weight to meet the mission. The results also include required revision to the engine and wing sizes. This frequently requires a new or revised design layout, in which the designer incorporates these changes and any others suggested by the effort to date.

The revised drawing, after some number of iterations, is then examined in detail by an ever-expanding group of specialists each of whom insures that the design meets the requirements of that specialty.

优化设计的结果包括了对完成任务所需的总重和燃料重量的更好的估计。结果还包含了对发动机和机翼尺寸的校正要求。这个结果通常要求一个新的或者校正过的设计布局。在这个新的设计布局中设计者集成了这些变化和许多设计更新。

经过许多次反复校正得到的设计图，这时要被一个不断扩大的专家组来详细的检查，每一个专家都要保证设计满足了本领域的要求。

For example, controls experts will perform a six-degree-of-freedom analysis to ensure that the designer’s estimate for the size of the control surfaces is adequate for control under all conditions required by design specifications. If not, they will instruct the designer as to how much each control surface must be expanded. If a larger aileron is required, the designer must ensure that it can be incorporated into the design without adversely affecting something else, such as the flaps or the landing gear.

The end product of all this will be an aircraft design that can be confidently passed to the preliminary design phase, as previously discussed. While further changes should be expected during preliminary design, major revisions will not occur if the conceptual design effort has been successful.

例如，控制专家要进行一个6自由度的分析来保证设计者对控制面尺寸的估算在各种情况下的控制效果足够满足设计规范的要求。如果达不到要求，他们会告知设计者每个控制面必须要扩大多少。如果需要一个更大的副翼，设计者必须要保证它能安装到原来的设计中，而不会对其它的部件产生不利的影响，如襟翼或者起落架。

所有这些工作最终的产品是一个可以放心的进入到初步设计阶段的飞机设计，正如前面所讲到的。尽管在初步设计阶段会有变动，但是如果概念设计是成功的，那么大的改动是不会发生的。

Text 3 Load on aircraft structural components

The structure of an aircraft is required to support two distinct classes of load; the first, termed ground loads, includes all loads encountered by the aircraft during movement or transportation on the ground such as taxying and landing loads, towing and hoisting loads while the second, air loads, comprises loads imposed on the structure during flight by manoevures and gusts. In addition aircraft designed for a particular role encounter loads peculiar to their sphere of operation. Carrier born aircraft for instance, are subjected to catapult take-off and arrested landing loads; most large civil and practically all military aircraft have pressurized cabins for high altitude flying; amphibious aircraft must be capable of landing on water and low altitude/high speed strike aircraft (e.g. Buccaneer) require a structure of above average strength to withstand the effects of flight in extremely turbulent air.

飞机的结构要承受两种截然不同类型的载荷。第一种称为地面载荷，包括飞机在地面运动或运输过程中遇到的所有载荷，如滑行和着陆载荷，牵引和爬升载荷等。第二种称为空气载荷，包括飞机在空中飞行的时候由于操作和扰流引起的施加在结构上的载荷。除此之外，为某项特定的任务设计的飞机，还要承受它应用的领域里特殊的载荷。例如运输机，就要承受弹射起飞和不良着陆载荷。大部分的民用飞机和几乎全部的军用飞机为了在高海拔飞行都有压力舱。两栖飞机必须能够降落在水面上而低空/高速攻击机（如掠夺者）需要高于平均强度水平的结构以承受在湍流空气中飞行的影响。

The two classes of loads may be further divided into surface forces which act upon the surface of the structure, e.g. aerodynamic and hydrostatic pressure and body forces which act over the volume of the structure and are produced by gravitational and inertial effects. Calculation of the distribution of aerodynamic pressure over the various surfaces of an aircraft’s structure is presented in numerous texts on aerodynamics and will therefore not be attempted here. We shall, however, discuss the types of load induced by these various effects and their action on the different structural components.

这两种类型的载荷可以进一步分解成表面力，即作用在结构表面的力，如气动力，流体静压体力和体力，体力是由重力和惯性的影响而引起的并作用在整个结构上的力。空气动力压力在飞机不同结构表面的分布的计算在大量的空气动力学文章中都有提到，所以这里就不再讲了。我们将讨论由这些不同的影响所产生的载荷的类型以及他们在不同的结构构件上的作用。

Basically all air loads are the resultants of the pressure distribution over the surfaces of the skin produced by steady flight, manoeuvre or gust conditions. Generally these resultants cause direct loads, bending, shear and torsion in all parts of the structure in addition to local, normal pressure loads imposed on the skin.

Conventional aircraft usually consist of fuselage, wings and tailplane. The fuselage contains crew and payload , the latter being passengers, cargo, weapons or fuel depending on the type of aircraft and its function; the wings provide the lift and the tailplane is the main contributor to directional control. In addition ailerons, elevators and rudder enable the pilot to manoeuvre the aircraft and maintain its stability in flight while wing flaps provide the necessary increase of lift for take-off and landing.

基本上所有的空气载荷都是由飞机在平稳飞行，操作和扰流情况下飞行在飞机蒙皮表面产生的压力分布合成的。除了施加在蒙皮上的局部法向压力，通常这些合力还会在飞机结构所有部件上产生直接载荷、拉伸、弯曲、剪切和扭转。

一般的飞机都包括机身、机翼和水平尾翼。机身装载机务人员和有效载荷。根据飞机的种类的功能后者可能是乘客、货物、武器或者燃料。机翼提供升力，尾翼是控制飞行方向的主要部件。另外，副翼、升降舵和方向舵保证让飞行员操纵飞机和保飞机飞行的平稳性，襟翼还能为飞机的起飞和降落提供额外的升力。

The force on an aerodynamic surface (wing, vertical or horizontal tail) results from a differential pressure distribution caused by incidence, camber or a combination of both. Such a pressure distribution has vertical (lift) and horizontal (drag) resultants acting at a center of pressure (C. P.). (In practice lift and drag are measured perpendicular and parallel to the flight path respectively). Clearly the position of the C. P . changes as the pressure distribution varies with speed or wing incidence. However there is conveniently a point in the aerofoil section about which the moment due to the lift and drag forces remains constant. Thus we replace the lift and drag forces acting at the C. P. by lift and drag forces acting at the aerodynamic center (A. C.) plus a constant moment M0.

加载到空气动力学表面（机翼、垂直和水平尾翼）的力是由迎角、倾角或者二者的共同作用导致的压力分布差引起的。这样的压力分布由垂直力和水平力合成作用在压力中心（实际上，升力和拉力的测量是按相对于航向的垂直和平行方向）。显然压力中心会随着压力分布因速度和机翼倾角的改变而变化。但是在机翼截面存在以一个点，使得升力和拉力对这个点的力矩保持不变。所以我们用把加载到压力中心的升力和拉力用加载到空气动力中心的拉力和升力加上一个固定的力矩M0代替。

While the chordwise pressure distribution fixes the position of the resultant aerodynamic load in the wing cross-section, the spanwise distribution locates its position in relation, say, to the wing root. Similar distributions occur on horizontal and vertical tail surfaces.

We see therefore that wings, tailplane and fuselage are each subjected to direct, bending, shear and torsional loads and must be designed to withstand critical combinations of these. Note that manoeuvres and gusts do not introduce different loads but result only in changes of magnitude and position of the type of existing loads. Over and above there basic in-flight loads fuselages may be pressurized and thereby support hoop stresses, wings may carry weapons and/or extra fuel tanks with resulting additional aerodynamic and body forces contributing to the existing bending, shear and torsion while the thrust and weight of engines may affect either fuselage or wings depending on their relative positions.

弦向压力分布固定在机翼连接部分合成作用空气动力载荷的位置，也就是说相对机翼根部，顺翼展方向的分布决定了它的位置。同样的应力分布也发生在水平和垂直尾翼表面上。

因此我们说机翼、尾翼和机身分别容易受到正向、弯曲、剪切和扭转载荷，它们必须设计成可以承受住这些力的临界合力。需要指出的是操作和扰流并不产生不同的力只是改变了已经存在的力的大小和位置。除了那些基本在飞行时承受的载荷以外，机身还可能受到挤压，因此它必须能支持环形压力。机翼可能携带武器或者副油箱，它们导致了额外的空气动力学作用力和内部作用力，这些作用力和已经存在的弯曲、剪切、扭转力共同作用，与此同时，发动机的推力和自重会影响到机身或者机翼，这取决于它们的相对位置。

Ground loads encountered in landing and taxying subject the aircraft to concentrated shock loads through the undercarriage system. The majority of aircraft have their main undercarriage located in the wings with nosewheel or tailwheel in the vertical plane of symmetry. Clearly the position of the main undercarriage should be such as to produce minimum loads on the wing structure compatible with the stability of the aircraft during ground manoeuvres. This may be achieved by locating the undercarriage just forward of the flexural axis of the wing and as close to the wing root as possible. In this case the shock landing load produces a given shear, minimum bending plus torsion.

Other loads include engine thrust on wings or fuselage which acts in the plane of symmetry but may, in the case of engine failure, cause severe fuselage bending moments, concentrated shock loads during a catapult launch and hydrodynamic pressure on the fuselages or floats of seaplanes

降落和滑行过程中产生的地面载荷通过起落架系统使飞机承受集中的冲击载荷。大部分的飞机在机翼两侧上垂直对称安装有带鼻轮或尾轮的主起落架。很明显主起落架应该具有使飞机在地面操作过程中能够对机翼结构产生最小载荷并能与飞机的稳定性进行协调的位置。可以通过把起落架定位在机翼曲轴的前面并尽可能的接近机翼的根部来实现。这样的情况下着陆冲击载荷产生了一个固定的剪切和一个最小的弯曲扭转力。

其他的载荷包括机翼或者机身上发动机的推力，其作用力在飞机上是对称的，但是可能，在发动机故障的情况下，会产生严重的机身扭转力矩，弹射起飞的时候产生的集中冲击载荷以及机身上的流体动力载荷和水上飞机的浮力作用。

初步设计Preliminary Design；详细设计Detail Design；大梁腹板spar web；加强筋stiffener ； 航空电子设备avionics ；层流laminar ；有效载荷payload ；下沉速度sink-speed, ；

失速速度stall speed || 飞机维修aircraft maintenance ；装配序列规划Assembly Sequence Planning /Assembly Sequence Plan；机身误差Fuselage error；精度precision/ accuracy/ degree of accuracy；数字化设计Digital Design；装配型架assembly jig；精密成形Precise Form/ precision form/ precise forming；干涉配合interference fit；弯曲强度bending strength /Flexural Strength/ bending break strength；翘曲变形buckling deformation/ Warpage；应力梯度stress gradient； 压电效应piezoelectric effect /piezoelectricity/piezoeffect；紧固件fastener/fastening piece/ Fixture Fastener；同步带synchronousbelt /timing belt/ hold-in range；单搭接Single lap； 裂纹扩展crack propagation /crack growth/ Crack Extension