机械工程专业英语翻译

原文：

Ideally，in designing any machine element，the engineer should have a this disposal the results of a great many strength tests of the particular material chosen. These tests should have been made on specimens 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 given service life. Whenever such data are available for design purposes，the engineer can be assured that he is doing the best possible job of engineering.

翻译：

设计任何机械零件的理想情况为，工程师可以利用他所选用的这种材料的大量的强度试验数据。这些试验使用的试样应该与他所设计的零件有着相同的热处理，表面粗糙度和尺寸，而且试验应该在与零件使用过程中承受的载荷完全相同的情况下进行。这意味着，如果零件将要承受弯曲载荷，那么就应该进行弯曲载荷的试验。如果零件将要承受弯曲和扭转的复合载荷，那么就应该进行弯曲和扭转复合载荷的试验。这些种类的试验可以提供非常有用和精确的数据。它们可以告诉工程师应该采用的安全系数和对于规定使用寿命时的可靠性。在设计过程中，只要能够获得这种数据，工程师就可以尽可能好地进行工程设计工作。

原文：

One of the primary considerations in designing any machine or structure is that the strength must be sufficiently greater than the stress to assure both safety and reliability. To assure that mechanical parts do not fail in service，it is necessary to learn why they sometimes do fail. Then we shall be able to relate the stresses with the strengths to achieve safety .

翻译：

在设计任何机器或者结构时，所考虑的主要问题之一是其强度应该比它所承受的应力要大得多，以确保安全与可靠性。要保证机械零件在使用过程中不失效，就必须知道它们在某些时候为什么会失效的原因，然后，我们才能将应力与强度联系起来，以确保其安全。

原文：

According to the cutting mechanism of helical milling technology，considering the machining characteristics of titanium alloy and geometric features of ball milling cutters，the shape and relative positional relationship between the tool and the workpiece at different characteristic moments were discussed，and four typical moments were selected to study the hole wall formation mechanism. The section characteristics and cross section area of the removed undeformed cutting materials were discussed，and the material removal behavior was analyzed through typical moments in the ball helical milling process. The experiments in ball helical milling of titanium alloy were carried out，the cutting forces were measured，and the tool wear and hole making quality were studied. The results showed that the materials removal process in ball helical milling is uniform and stable basically consistent with the simulation process，and the cutting forces increase or decrease gradually with slight tool wear and high hole-making quality.

翻译：

根据螺旋铣孔加工机理，考虑钛合金难加工特性及球头铣刀头部的几何特征，分析球头铣刀完成钛合金螺旋铣孔加工过程中不同特征时刻刀具和工件的形态及相对位置关系，选取四个典型时刻研究球头铣刀螺旋铣孔过程中的孔壁形成机理。对去除的未变形切削材料的截面特征和横截面面积进行讨论，通过典型时刻分析球头铣刀螺旋铣孔过程中的材料去除行为，在数控机床上开展钛合金螺旋铣孔试验，并测量切削力，分析刀具磨损和螺旋铣孔质量。结果显示球头铣刀在钛合金螺旋铣孔加工过程中材料去除均匀平稳，与仿真过程基本一致，同时切削力逐步增加或减小，刀具磨损小，孔质量较高。

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