机械类英语文章

在这种情况下，方法的可靠性带来了更多的significanttechniques已经先进的基于一个合理的评价所产生的风险。对一个给定的管过程中发挥的不确定性等方法enablequantitative违约风险评价（加载，propertiesmaterials，温度，等），和优化管设计中考虑风险[ 1 ]。考虑到可疑的mechanicalanalyses是最佳的robustdimensioning结构的一个必要条件。这一目标的LED的structuresfor几十年的力学发展的概率方法。这些方法使其部件或系统的可靠性和可能影响研究的设计变量对suchcomponents或系统行为的变化。耦合mechanicreliabilityengineering方法必须将越来越复杂机械建模（行为的非线性，动态，疲劳，断裂的过程，使reliabilityeffective等）和可利用的研究。这必要的复杂性causesanalyses越来越苛刻的机时。用高强度低合金钢制成管steelsare用来构造气transportingpressurized烃和长距离输油管道。管道纵向高量的应力由于内部压力，上覆土层，地面交通，和environmentalattacks可以导致损伤，特别是在没有passiveprotective涂层。这种损害是压力腐蚀开裂的主要原因，壁厚减薄，和应力集中[ 2 ]的存在。此外，制造过程中的管，热mechanicaldeformations经常产生的残余应力。产生的残余往往很高，有时接近materialyield强度；然而，其效果并不明显，直到结构完全加载或暴露于服务环境[ 1，3，4 ]。拉伸表面残余应力对疲劳损伤detrimentalbecause他们增加，构件的应力腐蚀敏感性，甚至断裂。这项工作的目的是由力学模型耦合，得到的概率统计训练一个近似模型。通过力学计算的数量来衡量该模型的有效性将需要建立一个强大的有关分析的替代品，这是可靠性和灵敏度。

Centrifugal force principles are also used in common appliances such as clothes dryers and in devices to control motor speeds and accelerate moving machines. Centripetal force causes an object to travel in circular path. 离心原理也可普遍应用于设备中，如：干衣机、马达转速控制器和加速设备。向心力使设备能做圆周运动。This action is caused by the continuous application of forces, which tend to pull the object to the center. In other words, the inward force, which resists the centrifugal force, is called the centripetal force. 这种运动依靠力的不间断施加来实现，这个力趋向于把物体拉向中心。或者说是对抗离心力的向内的力，这就是向心力。The centripetal force of objects spinning at a constant rate produces an acceleration toward the center which is equal and opposite to the centrifugal force.做恒速圆周运动的物体的向心力产生一个向心加速度，它的大小与离心力相等，方向相反。 The materials used in the construction of rapidly moving machine parts and mechanisms must be structurally strong enough to provide the centripetal force required to hold the parts to a circular path. ！！！！！此段有误，或能力不足，翻译不出来。！！！！！At the same time, the materials must be able to withstand the centrifugal force, which tends to pull the parts apart. Motion and the basic laws, which affect motion, are important considerations because of the numerous applications of these principles to produce work through mechanical devices. 同时，材料要承受得住有分离撕裂物体的离心力。运动形式和基本定律影响运动，应加以重视，因为很多机械装置是建立在基本定律的基础之上的。There are two primary mechanical motions: rotary and rectilinear. These terms suggest that rotary motion is a circular movement around a center line and rectilinear motion is a straight line motion. 有两种基本的机械运动：旋转运动和直线运动。旋转运动是围绕一条中心线的圆周运动，直线运动是在直线上的运动。For either rotary or rectilinear motion, it is possible, with added mechanical devices, to produce other forms of motion such as intermittent motion and reciprocating motion. 无论圆周运动还是直线运动，通过增加机械装置可以产生其他形式的运动，如：间歇运动和往复运动。Rotary Motion: The motion that is commonly transmitted is rotary motion. This type of motion may be produced with hand tools or power tools. Rotary motion is required to drill holes, turn parts in a lathe, mill surfaces, or drive a generator or fan belt.圆周运动：圆周运动是常用的传送运动。这种运动可以通过手动工具或动力工具产生。圆周运动可用于钻孔、车削、铣平面或者驱动发电机或风扇。Rectilinear Motion: The feed of a tool on a lathe, the cutting of steel on a power saw, or the shaping of materials are all situations in which rectilinear or straight line motion produces work. 直线运动：车刀的进给，在锯床上切割钢铁，或材料的成型都是直线运动的应用。In each of these situations a part or mechanism is used to change rotary motion to straight-line motion. The screw of a micrometer and the threads in a nut are still other applications where the direction of motion is changes from rotary to rectilinear. 在上述每种运动中，都有一个零件或机构用来将圆周运动转化为直线运动。千分尺和螺母上的螺纹是另一种将圆周运动转化为直线运动的应用。Harmonic and Intermittent Motion: Any simple vibration, such as the regular back, and forth movement of the end of a pendulum, is simple harmonic motion. However, many manufacturing processes require intermittent or irregular motion. 简谐运动和间歇运动：任何简单的振动，如钟摆的周期前后运动，就是简单的简谐运动。然而，很多制造工艺需求间歇运动或不规则运动。For example, the fast return stroke of a power hacksaw or shaper ram is desirable because no cutting is done on the return stroke. Therefore, as more time is saved in returning the cutting tool to the working position, the less expensive is the operation. 例如，快速回程电动弓锯是高效的，因为在回程中没有切削作用。所以，回程时间越短，越经济。The combinations of rotary and rectilinear motion obtainable are unlimited because of the large variety of parts such as gears, cams, pulleys, screws, links, and belts, which can be combined in many arrangements.圆周运动和直线运动的组合有无限种可能，因为大量的零件，如：齿轮、凸轮、滑轮、螺纹、连杆和皮带，能以多种形式组合起来。