机械专业英语试题及答案(2)

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One principle aim of kinematics is to create (design) the desired motions of the subjects’ mechanical parts and then mathematically compute the positions, velocities, and accelerations, which those will create on the parts. Since, for most earthbound mechanical systems, the mass remains essentially constant with time, defining the accelerations as a function of time then also defines the dynamic forces as a function of time. Stresses, in turn, will be a function of both applied and inertial (ma) forces. Since engineering design is charged with creating systems which will not fail during their expected service life, the goal is to keep stresses within acceptable limits for the materials chosen and the environmental conditions encountered. This obviously requires that all system forces be defined and kept within desired limits. In machinery, the largest forces encountered are often those due to the dynamics of the machine itself. These dynamic forces are proportional to acceleration, which brings us back to kinematics, the foundation of mechanical design. Very basic and early decision in the design process involving kinematic principles can be crucial to the success of any mechanical design; a design which has poor kinematics will prove troublesome and perform badly.

Any mechanical system can be classified according to the number of degree of freedom (DOF) which it processes. The system’s DOF is equal to the number of independent parameters which are needed to uniquely define its position in space at any instant of time.

A rigid body free to move within a reference frame will, in the general case, has complex motion, which is a simultaneous combination of rotation and translation. In three-dimensional space, there may be rotation about any axis and also simultaneous translation which can be resolved into components along three axes. In a plane, or two-dimensional space, complex motion becomes a combination of simultaneous rotation about one axis (perpendicular to the plane) and also translation resolved into components along two axes in the plane

41、Kinematics research focus on the following EXCEPT ______..

A) accelerations B) force C) positions, D) velocities

42、From the passage that for the design engineer the first and most important is____

A) the service life of a machine B) the materials choose C) the degree of freedom D) kinematic principles

43、An mechanical system has uniquely defined position in space at any instant of time that ___.

A) It should has one DOF B) It should Has two DOF

C) the DOF and the number of independent parameters should equal D) It should has any DOF as want

44、 which one of the following is NOT TRUE _______?.

A) A rigid body free to move in three-dimensional space may rotation about any axis

B) A rigid body free to move in three-dimensional space is a simultaneous combination of rotation and translation

C) A rigid body free to move in three-dimensional space can be resolved into components along three axes

D) A rigid body free to move in three-dimensional space may has complex motion

45、The best title for this passage would be _______.

A) kinematics B) dynamics

C) kinematics and dynamic D) the important of kinematics

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专 业

四、 英译汉（共20分）

1．将下列英语句子译成汉语（共5小题，每小题2分）

（1）A perfectly rigid or inextensible link can exist only as a textbook type of model of a real machine member.

（2）Foundations should ensure the machine’s stiffness; shock absorption and isolation are secondary considerations.

(3)Thus, if a mechanical component such as a spring is subjected to repetitive or cyclical applications of stress levels much lower than the ultimate strength, it will fracture after a large number of repetitions of this stress.

（4）Interchangeability means that identical parts must be interchangeable, i.e., able to replace each other, whether during assembly or subsequent maintenance work; without the need for any fitting operations.

（5）A gear can be gripped axially between a shoulder on the shaft and a spacer, with torque being transmitted through a key.

2、将下段英语翻译成汉语（10分）

As we look around us we see a world full of “things”, machines, devices, tools, things that we have designed, built, and used; things made of wood, metals, ceramics, and plastics. We know from experience that some things are better than others; they last longer, cost less, are quieter, or are ease to use. Ideally , however, every such item has been designed according to some set of “functional requirements” as perceived by the designers—that is, it hs been designed so as to answer the question, “exactly what function should it perform?” In the world of engineering, the major function frequently is to support some type of loading due to weight, inertia , pressure, etc.

班 级 学 号 装 姓 名 订

五、英译汉（共20分）

1、将下列句子译成英语（共5小题，每小题2分）

线

（1）一个或多个诸如齿轮，链轮，皮带轮和凸轮等类的构件通常借助于销、键、

花键、卡环或其它装置连接到轴上。

（2）运动学仅研究机构的运动，而不考虑作用在机构上的力。

（3）工程上的许多问题在其本质上是非线性的，也就是说恢复力并不与位移成正比，而且阻尼力也不与速度的一次方成正比。

（4）在物体上所画的一条基准线，只会改变他的位置，而不会改变他的角度方向。

（5）当一个装置意外地失效后，通常需要进行研究工作，来找出失效的原因和确定可能的改正措施。

2. 将下段汉语翻译成英语（10分）

密度：材料的密度是指单位体积材料的质量。另外一个术语是比重，其表示某种材料的密度与水的密度的比值，因此，比重没有单位。对于如飞机和航天结构、汽车车体和部件，以及其他一些产品，当能量消耗和动力限制是主要考虑的因素时，减轻重量尤其重要。在设计先进的设备与机器和设计诸如汽车等消费品的过程中，采用新的替代材料来减轻重量和降低成本是一个应该着重考虑的问题

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专业英语 参考答案及评分标准 （重修）

一、选择题: （本大题共15小题，每小题1分，总计15分） 1-5：BCDCB 6-10：ACBCA 11-15 DACAB

二、完形填空：（本大题共15小题，每小题1分，总计15分） 16-20：BDABC 21-25 ：BABDB 26-30：CBCAD 三、阅读理解：（本大题共20小题，每小题2分，总计40分） 31-35：ADABC 36-40 ：BC ACD 41-45： BDCA C 四、翻译（满分40分）

1、英译汉，(共5小题，每小题2分)

（1）A perfectly rigid or inextensible link can exist only as a textbook type of model of a real machine member.

一个绝对刚性或者不可伸长的构件只能作为真实机器零件在教科书中的模型而存在。

（2）Foundations should ensure the machine’s stiffness; shock absorption and isolation are secondary considerations.

基础应该保证机器的刚度，减震和隔离是次要的考虑事项。

(3)Thus, if a mechanical component such as a spring is subjected to repetitive or cyclical applications of stress levels much lower than the ultimate strength, it will fracture after a large number of repetitions of this stress.

因此，像弹簧这样的机械零件，在比其极限强度低很多的重复应力或周期性应力下，经过很多次的重复作用之后也会发生断裂.

（4）Interchangeability means that identical parts must be interchangeable, i.e., able to replace each other, whether during assembly or subsequent maintenance work; without the need for any fitting operations.

互换性意味着在相同的零件之间必须能够进行互换。无论是在装配时还是在其后的维修时，这些零件都可以互相取代而不需任何修配工作。

（5）A gear can be gripped axially between a shoulder on the shaft and a spacer, with torque being transmitted through a key.

一个齿轮可以用轴肩和挡圈进行轴向固定，并通过键来传递。

2、英译汉，10分

As we look around us we see a world full of “things”, machines, devices, tools, things that we have designed, built, and used; things made of wood, metals, ceramics, and plastics. We know from experience that some things are better than others; they last longer, cost less, are quieter, or are ease to use. Ideally , however, every such item has been designed according to some set of “functional requirements” as perceived by the designers—that is, it hs been designed so as to answer the question, “exactly what function should it perform?” In the world of engineering, the major function frequently is to support some type of loading due to weight, inertia , pressure, etc.

当我们环顾四周，我们可以看到一个充满“物体”的世界，机器、设备、工具等一切由我们设计、建造和使用的物体；有木头、金属、水泥和塑料制成的物体。从我们的经验我们知道一些物体会比其他一些物体更好，如使用寿命更长，成本更低，更轻便或者更容易使用。 然而，在理想的情况下，每一件产品都是设计人员根据其对某些“功能要求”的理解而设计出来的，也就是说，在设计过程中，应该回答这样的问题，即“它应该具有那种确切的功能？” 在工程界中，最经常的功能是支撑一些由于重量、惯性力及压力等引起的载荷。

3、汉译英(共5小题，每小题2分)

（1）一个或多个诸如齿轮，链轮，皮带轮和凸轮等类的构件通常借助于销、键、花键、卡环或其它装置连接到轴上。

One or more members such as gears, sprockets, pulleys, and cams are usually attached to the shaft by means of pins, keys, splines, snap rings, and other devices.

（2）运动学仅研究机构的运动，而不考虑作用在机构上的力。

Kinematics is the study of motion in mechanisms without reference to the forces that act on the mechanism.

（3）工程上的许多问题在其本质上是非线性的，也就是说恢复力并不与位移成正比，而且阻尼力也不与速度的一次方成正比。

Many vibration problems in engineering are nonlinear in nature, i.e. the restoring forces are not proportional to the displacements and the damping forces are not proportional to the first power of the velocity. （4）A reference line drawn on the body changes its linear position but does not change its angular orientation.

在物体上所画的一条基准线，只会改变他的位置，而不会改变他的角度方向。

（5）当一个装置意外地失效后，通常需要进行研究工作，来找出失效的原因和确定可能的改正措施。

When a device fails (unexpectedly) it is often necessary to carry out a study to pinpoint the cause of failure and to identify potential corrective measures 4、汉译英，10分

密度：材料的密度是指单位体积材料的质量。另外一个术语是比重，其表示某种材料的密度与水的密度的比值，因此，比重没有单位。对于如飞机和航天结构、汽车车体和部件，以及其他一些产品，当能量消耗和动力限制是主要考虑的因素时，减轻重量尤其重要。在设计先进的设备与机器和设计诸如汽车等消费品的过程中，采用新的替代材料来减轻重量和降低成本是一个应该着重考虑的问题

Density: the density of a material is its mass per unit volume. Another term id specific gravity, which express a material’s density in relation to that of water, and thus, it has no units.Weight saving is important particularly for aircraft and aerospace structures, for automotive bodies and components, and for other products where energy consumption and power limitations are major concerns. Substitution of materials for the sake of weight saving and economy is a major factor in the design both of advanced equipment and machinery and of consumer products, such as automobiles.

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