机械制造专业英语--课后答案(部分)

专业英语翻译一stressandstrain（应力与应变）1thefundamentalconcepts基本概念crosssection横截面theinternalstressesproducedinthebar杆的内应力continuousdistributionofhydrostaticpressure流体静压力thetensileload拉伸载荷auniformdistributionoverthecrosssection在横截面均匀分布arbitrarycross-sectionalshape任意截面形状tensilestresses拉应力compressivestresses压应力anormalstress正应力throughthecentroidofthecrosssectionalarea通过横截面形心theuniformstresscondition压力均匀分布thestressdistributionattheendsofthebar杆末端应力分布highlocalizedstresses高度应力集中anaxiallyloadedbar轴向载荷杆件atensilestrain拉应变anelongationorstretchingofthematerial材料拉伸acompressivestrain压应变theratiooftwolengths两个长度的比值purelystaticalandgeometricalconsiderations从纯静态以及几何角度考虑1.Thatbranchofscientificanalysiswhichmotions,timesandforcesiscalledmechanicsandismadeupoftwoparts,staticsanddynamics.研究位移、时间和力运动乘力是科学分析法的一个分支，被称作力学，力学由两大部分组成，静力学和动力学。2.Forexample,iftheforceoperatingonasleevebearingbecomestoohigh,itwillsqueezeouttheoilfilmandcausemetal-to-metalcontact,overheatingandrapidfailureofthebearing.例如：如果止推轴承上的作用力过大的话，会挤出油膜，引起金属和金属之间的相互接触，轴承将过热而迅速失效。3.Ourintuitiveconceptofforceincludessuchideasasplaceofapplication,direction,andmagnitude,andthesearecalledthecharacteristicsofaforce.力的直观概念包括力的作用点、大小、方向，这些被称为力的三要素。4.Allbodiesareeitherelasticorplasticandwillbedeformedifacteduponbyforces.Whenthedeformationofsuchbodiesissmall,theyarefrequentlyassumedtoberigid,i.e.,incapableofdeformation,inordertosimplifytheanalysis.所有的物体既可以是弹性的也可以是塑性的，如果受到力的作用就产生变形。当变形很小的时候它们被假设成刚体，也就是不产生变形。5.Therigid-bodyassumptioncannotbeusedininternalstressesandstrainsduetotheappliedforcestobeanalyzed.Thusweconsiderthebodytobecapableofdeforming.刚体假设不能应用于内应力和内应变的分析，所以在实际力的分析时，要考虑物体的形变。6.Ifalltheforcesactingonaparticlearebalanced,theparticlewilleitherremainatrestorwillcontinuetomoveinastraightlineatauniformvelocity.如果作用在质点上所有的力是平衡的，质点将会保持静止或做做匀速直线运动。21)themainmanifestationsofcapacity主要的表现能力2)themaximumunitload（stress）最大单位载荷（应力）3）stress-straindiagram应力—应变图4）thesimpletensiletest简单的拉伸试验5）thepercentageelongationatrupture断裂伸长率6）theendsoftensilespecimens拉伸试样的两端7）permanentdeformation永久变形8）theresultingload-displacementcurve由此产生的载荷位移曲线9）asubstantialyieldingofthematerial大量产生的物质10）yieldpoint屈服点11)thetransitionfromelastictoplasticbehavior从弹性到塑性的过度12）materialpropertytable材料属性表13）plasticdeformation塑性变形14）aspecifiedstandardlengthofthespecimen指定的标准式样长度15）atthemomentofrupture此刻的破裂16）shortcylindricalspecimens短圆柱标本17）ductilematerials韧性材料18）highstressconcentration高应力集中19）ultimatetensilestrength极限抗拉强度20）strainhardeningzone应变硬化区1)Atensiletestconsistsofslowlypullingasampleofmaterialwithatensileloaduntilitbreaks.Theendsoftensilespecimensareusuallyenlargedtoprovideextraareaforgrippingandtoavoidhavingthesamplebreakwhereitisbeinggripped.拉伸试验包括慢慢加载拉伸载荷直到断裂，拉伸试件两端加粗为了提供装夹区域和避免试件断裂。2）Theusualmannerofconductingthetestistodeformthespecimenataconstantspeed.Forexample,intheUniversaltestingmachines,themotionbetweenthefixedandmovingcrossheadscanbecontrolledataconstantspeed.通常进行试验的方法就是使试件以恒定速度发生变形。例如，在万能拉伸试验机上，固定端和移动的十字滑块之间的变形是以恒定速度进行的。3）Theloadthatmustbeappliedtoenforcethisdisplacementratevariesasthetestproceeds.ThisloadFmaybedividedbythecross-sectionalareaAtoobtainthestressinthespecimenatanytimeduringthetest.随着实验的进行，用来产生位移的载荷是随位移的变化而变化。在实验中，载荷F除以横截面积A可以得到任意时刻点的应力。4）HoweveractualmeasurementofΔLispreferablewhereThisisfeasible.Stressandstrainbasedontheinitial(undeformed)dimensions,AiandLi,arecalledengineeringStressandstrain.然而，在可行的位置的ΔL的实际测量是更可取的，基于原始尺寸Ai和Li的应力和应变称为工程应力和工程应变。5)Ductileandbrittlematerialsbehavedifferentlyincompressiontestaswell.ThecompressiontestisconductedonshortCylindricalspecimensplacedbetweenparallelplates.塑性和脆性材料在压缩试验中表现的特性是不相同的。压缩试验是把短圆柱形试件放在两平行平板之间进行的6）Thecompressiontestdiagramforthesematerialsretains.Thequalitativefeaturesofthetensiontestdiagram.Theultimatecompressivestrengthofabrittleofabrittlematerialisdeterminedinthesamewayasintension.材料压缩试验图保持了拉伸试验图性能上的特征。脆性材料的最大压缩强度与最大拉伸强度得到的方法相同。第三单元Virtuallyallmachinescontainshafts.Themostcommonshapeforshaftsiscircularandthecrosssectioncanbeeithersolidorhollow(hollowshaftscanresultinweightsavings).几乎所有的机器都有轴，最常用的外形是圆形的，横截面是空心的或实心的圆形截面（空心轴可以减少重量）。Ashaftmusthaveadequatetorsionalstrengthtotransmittorqueandnotbeoverstressed.Itmustalsobetorsionallystillenoughsothatonemountedcomponentdoesnotdeviateexcessivelyfromitsoriginalangularpositionrelativetoasecondcomponentmountedonthesameshaft.一个轴必须有足够的扭转强度来传递扭矩而不会破坏，同样也必须有足够的扭转刚度，这样安装轴就不能过度偏离相对于安装在同一轴上第二个零件的原始位置。Shaftsaremountedonbearingsandtransmitpowerthroughsuchdevicesasgears,pulleys,camsandclutches.Thesedevicesintroduceforceswhichattempttobendtheshaft;hence,theshaftmustberigidenoughtopreventoverloadingofthesupportingbearings.轴安装在轴承上通过齿轮，滑轮，凸轮和离合器这些装置传递力。这些装置可以产生使轴弯曲的力，所以轴必修有足够的刚性防止支撑轴承的过载。Inaddition,theshaftmustbeabletosustainacombinationofbendingandtorsionandbending.另外，轴必须能承载弯扭组合的载荷，因此，这样就必须考虑弯扭组合的等效载荷。Componentssuchasgearsandpulleysaremountedonshaftsbymeansofkey.Thedesignofthekeyandthecorrespondingkeywayintheshaftmustbeproperlyevaluated.齿轮和滑轮构件是用键的方式连接在轴上的，键和对应的键槽的设计必须进行估算。Anotherimportantaspectofshaftdesignisthemethod