机械专业英语最新版本.ppt

单词复习：
concurrentengineeringdesign
deem
Integral
reciprocatingmotion/circularmotion
internalcombustionengine
AccreditationBoardforEngineeringandTechnology
moderndesigntheoryandmethodologyLesson7EngineeringDesignandsafetyfactors工程设计和安全系数Paragraph1Murphy’sLaw:Ifanymaterialcanfail,itwill.
Lawsofmaterialsapplications
(1)Allmaterialsareunstable.
(2)Thematerialssystemisonlyasstrongorasstableasitsweakestormostunstablecomponent.

墨菲法则：如果任何材料有可能出问题，它（系统）终将出问题。
材料应用法则：（1）任何材料都是不牢固的；（2）材料系统的强度和牢固程度仅仅像它最薄弱的、最不牢固的部分。Paragraph2:Understress(应力，strain应变),allmaterialsrespondtothatstress.
Creep(蠕变)isanexample.
Givenenoughtime,failure(失效)canbecalculatedtooccurinallmaterialsundercreepstress.

在压力作用下，所有材料都会有变化。蠕变(creep)是一个例子。在蠕变压力作用下，若有足够的时间，所有材料一定会产生屈服。Creepdeformation蠕变变形Stressandenvironmentcanactinconcerttocausefailure,forexample,stresscorrosioncracking.
Creep-temperatureeffectsandstress-temperatureeffectscancontributetothedegradationofpropertiesandcomponentsandsystemfailure.

压力和环境共同（inconcert）作用会造成屈服，例如，应力腐蚀裂纹。蠕变温度影响和应力—温度影响都会导致性能降低、零件和系统失败。ThedesignprocessParagraph3:Thedesigncyclecaninvolvetheoriginalthoughts,sketches,andknowledgethatinthespecificationstageproduceengineeringdrawings.
设计循环涉及最初的构想、草图、在详细描述阶段绘制工作图的知识。
Computer-aideddesign(CAD,CAM计算机辅助制造)isnowemployedtoimplementacycleinwhichvariousdesignsordesignideasmaybetestedorsimulated.
计算机辅助设计现在已用于设计过程，各种设计和设计思想能被检验和仿真。Paragraph4:Priortoafabricationstep,materialsspecificationsmustbemadedependinguponthedesignrequirements.

在制造之前必须依据设计要求给出材料的技术要求（specification）。Thesemayhavetobealteredinthedesignsimulationiftherequisitepropertiescannotbeidentifiedinexistingmaterials,orfabricationmayhavetodelayuntilnewmaterialscanbedesignedandfabricated.
Materialsaretherealityinadesign.

如果现存的材料不具备必要的性能，或者只有新材料开发出来才能制造，在设计仿真阶段就必须改动这些材料的技术要求。在设计中材料是现实的。Paragraph5ThedesignordesignimplementationdiagramshowninFigure1maynotcharacterizethefinalproduct.
图1示意图或许不能描述最终产品。
Thefirstprocessmayproduceaprototype(RapidPrototyping)thatwillbetestedandimprovedupontodev