機(jī)械設(shè)計(jì)制造及其自動(dòng)化專業(yè)英語-Design-of-machine-and-machine-elements-課件

wordrugged[?r?gid]a.

結(jié)實(shí)的，堅(jiān)固的

fillet[?filit]n.

嵌條，(內(nèi))圓角

notch[n?t?]n.

;vt.

槽口，凹口，刻痕，開槽

tolerance[?t?l?r?ns]n.;vt.

公差，容許量nuisance[?nju:sns]

n.討厭的人或東西，麻煩事

loosen[?lu:sn]v.

解開，放松，松開

radiator[?reidieit?]

n.

散熱器，電暖爐，輻射體

Designofmachineandmachineelements1wordfracture[?fr?kt??]v.

;n.(使)斷裂，(使)破裂[碎]

wear[w??]v.

;n.

磨損[蝕，破，壞]，損耗(量)

stressconcentration應(yīng)力集中

geometric[d?i??metrik]a.

幾何的，幾何學(xué)的discontinuity[?dis?conti?nju(:)iti]

n.間斷，不連續(xù)，中斷

Designofmachineandmachineelements2MachinedesignMachinedesignistheartofplanningordevising[d??va?z??]

neworimprovedmachinestoaccomplishspecificpurposes.Ingeneral,amachinewillconsistofacombinationofseveraldifferentmechanicalelementsproperlydesignedandarrangedtoworktogether,asawhole.機(jī)器設(shè)計(jì)是計(jì)劃或設(shè)計(jì)(發(fā)明)新的或改進(jìn)機(jī)器以達(dá)到特定目的的藝術(shù)。一般來說，一臺(tái)機(jī)器將由幾個(gè)不同的機(jī)械元件組合而成，它們被適當(dāng)?shù)卦O(shè)計(jì)和排列成一個(gè)整體。3MachinedesignDuringtheinitialplanningofamachine,fundamental[?f?nd??ment?l]

decisions[d??s???n]

mustbemadeconcerningloading,typeofkinematic[?k?n?‘m?t?k]

elementstobeused,andcorrectutilization[?jut?la??ze??n]

ofthepropertiesofengineeringmaterials.在對(duì)機(jī)器進(jìn)行初步規(guī)劃時(shí)，必須對(duì)裝載、使用的運(yùn)動(dòng)(學(xué)的)元件的類型和工程材料的正確使用作出基本決定。4MachinedesignEconomic[?i:k??nɑ:m?k]

considerationsareusuallyofprime[pra?m]

importancewhenthedesignofnewmachineryisundertaken.Ingeneral,thelowestover-allcostsaredesigned.在設(shè)計(jì)新機(jī)器時(shí)，經(jīng)濟(jì)的因素通常是最重要的。一般來說，選擇總成本最低的設(shè)計(jì)方案。undertaken

[??nd?‘te?k?n]

v.擔(dān)任;著手5MachinedesignConsiderationshouldbegivennotonlytothecostofdesign,manufacture,saleandinstallation,butalsotothecostofservicing

[?s?:rv?s??].Themachineshouldofcourseincorporate[?n?k?:rp?re?t]

thenecessarysafetyfeaturesandbeofpleasingexternalappearance.不僅要考慮設(shè)計(jì)、制造、銷售和安裝的費(fèi)用，還要考慮服務(wù)的成本。機(jī)器當(dāng)然應(yīng)該包括必要的安全特性和美觀的外形。pleasing

[?pliz??]

adj.令人愉快的，討人喜歡的6MachinedesignTheobjectiveistoproduceamachinewhichisnotonlysufficiently[s??f???ntl?]rugged[?r?ɡ?d]tofunctionproperlyforareasonablelife,butisatthesametimecheapenoughtobeeconomically[?i:k??nɑ:m?kli]

feasible

[?fiz?b?l].目標(biāo)是要生產(chǎn)一臺(tái)機(jī)器，它不僅在合理壽命期內(nèi)堅(jiān)固耐用，同時(shí)價(jià)格低廉足以在經(jīng)濟(jì)上是可行的。7MachinedesignTheengineerinchargeofthedesignofamachineshouldnotonlyhaveadequate[??d?kw?t]

technicaltraining,butmustbeamanofsoundjudgmentandwideexperience,qualitieswhichareusuallyacquiredonlyafterconsiderabletimehasbeenspentinactualprofessionalwork.負(fù)責(zé)設(shè)計(jì)一臺(tái)機(jī)器的工程師，不僅應(yīng)有足夠的技術(shù)訓(xùn)練，而且還必須是一個(gè)有正確(良好的)判斷力和豐富經(jīng)驗(yàn)的人，只有花費(fèi)大量(相當(dāng)大的)時(shí)間從事實(shí)際專業(yè)工作后才能獲得這種素質(zhì)。8DesignofmachineelementsTheprinciplesofdesignare,ofcourse,universal

[?ju:n??v?:rsl].Thesametheoryorequationsmaybeappliedtoaverysmallpart,asinaninstrument[??nstr?m?nt],or,toalargerbutsimilarpartusedinapieceofheavyequipment.當(dāng)然，設(shè)計(jì)原則是普遍的。同樣的理論或公式可以應(yīng)用于一個(gè)非常小的零件上，如在一個(gè)儀器中，或在一個(gè)重型設(shè)備中使用的較大但相似的零件上。9DesignofmachineelementsInnocase,however,shouldmathematical[?m?θ??m?t?k?l]

calculations[k?lkj?‘le??nz]

belookedupon[??pɑ:n]asabsoluteandfinal.Theyareallsubject[?s?bd?ekt]

totheaccuracy[??kj?r?si]ofthevariousassumptions[?'s?mp?nz],whichmustnecessarily[?n?s??s?r?li]bemadeinengineeringwork.既然如此，毫無疑問，數(shù)學(xué)計(jì)算不應(yīng)該被看作是絕對(duì)的和最終的。它們都要服從(adj)各種假設(shè)的準(zhǔn)確性，而這些假設(shè)必須(的)在工程工作中進(jìn)行。10DesignofmachineelementsSometimesonlyaportion[?p?:r?n]ofthetotalnumberofpartsinamachinearedesignedonthebasisofanalytic[??n??l?t?k]calculations.Theformandsizeoftheremainingpartsarethenusuallydeterminedbypracticalconsiderations.有時(shí)，機(jī)器中零件的總數(shù)量只有一部分是在分析計(jì)算的基礎(chǔ)上設(shè)計(jì)的。其余部分的形狀和尺寸通常由實(shí)際考慮來確定。11DesignofmachineelementsOntheotherhand,ifthemachineisveryexpensive,orifweightisafactor,asinairplanes,designcomputationsmaythenbemadeforalmostalltheparts.另一方面，如果機(jī)器非常昂貴，或者重量是一個(gè)因素，就像飛機(jī)一樣，那么幾乎所有零件都可以進(jìn)行設(shè)計(jì)計(jì)算。12DesignofmachineelementsThepurposeofthedesigncalculationsis,ofcourse,toattempttopredictthestressordeformationinthepartinorderthatitmaysafelycarrytheloads,whichwillbeimposedonit,andthatitmaylastfortheexpectedlifeofthemachine.設(shè)計(jì)計(jì)算的目的當(dāng)然是試圖預(yù)測(cè)零件的應(yīng)力或變形，以便它能夠安全地承受載荷，這是必要的，并且其也許會(huì)影響到機(jī)器的預(yù)期壽命。impose[?m?po?z]

vt.強(qiáng)加13DesignofmachineelementsAllcalculationsare,ofcourse,dependentonthephysicalpropertiesoftheconstruction[k?n?str?k??n]

materialsasdeterminedbylaboratorytests.當(dāng)然，所有的計(jì)算都取決于實(shí)驗(yàn)室試驗(yàn)所確定的建筑(工程)材料的物理性質(zhì)。14DesignofmachineelementsArationalmethodofdesignattemptstotaketheresultsofrelativelysimpleandfundamentaltestssuchastension,compression,torsion,andfatigueandapplythemtoallthecomplicatedandinvolvedsituationsencounteredinpresent-daymachinery.一種合理的設(shè)計(jì)方法，試圖將相對(duì)簡(jiǎn)單而基本的測(cè)試結(jié)果，如拉伸、壓縮、扭轉(zhuǎn)和疲勞等結(jié)果及應(yīng)用到當(dāng)今機(jī)械所遇到的所有復(fù)雜和牽涉的情況中。15DesignofmachineelementsInaddition,ithasbeenamply[‘?mpl?]

provedthatsuchdetailsassurfacecondition,fillets

[?f?l?ts],notches[n?t?],manufacturingtolerances,andheattreatmenthaveamarketeffectonthestrengthandusefullifeofamachinepart.另外，充分證明了表面條件、圓角、缺口、加工公差和熱處理等細(xì)節(jié)對(duì)機(jī)械零件的強(qiáng)度和使用壽命有著一定的影響。16DesignofmachineelementsThedesignanddraftingdepartmentsmustspecify[?sp?s??fa?]completelyallsuchparticulars,andthusexercisethenecessaryclosecontroloverthefinishedproduct.設(shè)計(jì)和起草部門必須明確規(guī)定所有這些細(xì)節(jié)，從而對(duì)成品進(jìn)行必要的嚴(yán)格控制。exercise[?eks?rsa?z]

n.運(yùn)動(dòng)vi.練習(xí)17DesignofmachineelementsAsmentionedabove,machinedesignisavast[v?st]fieldofengineeringtechnology.Assuch,itbeginswiththeconceptionofanideaandfollowsthroughthevariousphasesofdesignanalysis,manufacturing,marketing,andconsumerism[k?n?sju:m?r?z?m].綜上所述，機(jī)械設(shè)計(jì)是一個(gè)巨大的工程技術(shù)領(lǐng)域。例如，從設(shè)計(jì)理念到設(shè)計(jì)分析的每一個(gè)階段，制造，市場(chǎng)及銷售。18DesignofmachineelementsThemajorareasofconsiderationinthegeneralfieldofmachinedesignareasfollows:1)Initialdesignconception2)

Strengthanalysis

3)

Materialsselection4)

Appearance

5)

Manufacturability

6)Economy[??kɑ:n?mi]

7)

Safety

8)

Environment[?n?va?r?nm?nt]

effects

9)Reliabilityandlife10)Legalconsiderations在機(jī)械設(shè)計(jì)的一般領(lǐng)域中，主要考慮的范疇如下：1)初步設(shè)計(jì)構(gòu)思

2)強(qiáng)度分析

3)材料選擇

4)外觀

5)可制造性

6)經(jīng)濟(jì)性

7)安全

8)環(huán)境效應(yīng)(果)

9)可靠性和壽命

10)合法(法律)的考慮19FailureAnalysisandDimensionalDeterminationItisabsolutelyessential[??s?n??l]thatadesignengineerknowshowandwhypartsfailsothatreliablemachineswhichrequireminimummaintenancecanbedesigned.Sometimes,afailurecanbeserious,suchaswhenatire

blows[blo?]

outonanautomobiletravelingathighspeeds.顯而易見的設(shè)計(jì)工程師必須(必要的)知道零件的故障原因，這樣就可以設(shè)計(jì)出最低維護(hù)要求而可靠的機(jī)器。有時(shí)，故障可能是嚴(yán)重的，例如當(dāng)輪胎在高速行駛的汽車上爆胎時(shí)。20FailureAnalysisandDimensionalDeterminationOntheotherhand,afailuremaybenomorethananuisance.Anexampleisthelooseningoftheradiatorhoseintheautomobilecoolingsystem.Theconsequenceofthislatterfailureisusuallythelossofsomeradiatorcoolant,aconditionwhichisreadily[?r?d?li]

detectedandcorrected.另一方面，失效是一件討厭的事。汽車?yán)鋮s系統(tǒng)中散熱器軟管的松動(dòng)就是一個(gè)例子。這種故障的后果通常是一些散熱器冷卻劑的損耗，這種情況很容易被檢測(cè)和糾正。21FailureAnalysisandDimensionalDeterminationThetypeofloadapartabsorbs[?b?s?:rbz]

isjustassignificantasthemagnitude.Generallyspeaking,dynamicloadswithdirectionreversals[r?'v?:slz]causegreaterdifficultiesthanstaticloadsand,therefore,fatiguestrengthmustbeconsidered.零件吸收的載荷類型是相當(dāng)重要的。一般來說，有方向反轉(zhuǎn)的動(dòng)載荷比靜載荷造成更大的困難，因此必須考慮疲勞強(qiáng)度。22FailureAnalysisandDimensionalDeterminationAnotherconcerniswhetherthematerialisductileorbrittle[?br?tl].Forexample,brittlematerialsareconsideredtobeunacceptablewherefatigueisinvolved.另一個(gè)問題是這種材料是韌性的還是易碎的。例如，在涉及疲勞的情況下，易碎的材料被認(rèn)為是不可接受的。ductility[d?k'tiliti]n.延(展)性，韌性

fragility[fr?‘d??l?t?]

n.脆性23FailureAnalysisandDimensionalDeterminationManypeoplemistakinglyinterpret[?n?t?:rpr?t]thewordfailuretomeantheactualbreakageofapart.However,adesignengineermustconsiderabroader[b'r?:d?r]understandingofwhatconstitutes['k?nst?tju:ts]failure.許多人錯(cuò)誤地解釋“失敗”這個(gè)詞意味著一個(gè)零件的實(shí)際破壞。然而，設(shè)計(jì)工程師必須考慮更廣泛的理解是什么構(gòu)成了失敗。24FailureAnalysisandDimensionalDeterminationForexample,abrittlematerialwillfailundertensileloadbeforeanyappreciable[??pri??b?l]deformationoccurs

[?‘k?:z].Aductilematerial,howeverwilldeformalargeamountprior[?pra??]torupture

[?r?pt??].例如，易碎的材料在任何明顯的(相當(dāng)可觀的)變形發(fā)生之前都會(huì)在拉伸載荷下失效。然而，韌性材料在破裂之前會(huì)大量變形。25FailureAnalysisandDimensionalDeterminationExcessive[?k?s?s?v]deformation,withoutfracture,maycauseamachinetofailbecausethedeformedpartinterferes[??nt?r?f?rz]

withamovingsecondpart.過大的變形，沒有斷裂，可能導(dǎo)致機(jī)器失效，因?yàn)樽冃尾糠指蓴_(干涉)移動(dòng)的第二部分。26FailureAnalysisandDimensionalDeterminationTherefore,apartfails(evenifithasnotphysicallybroken)wheneveritnolongerfulfills[f?l?f?l]itsrequiredfunction.

Sometimesfailuremaybeduetowearthatcanchangethecorrectpositionofmating

[?me?t??]parts.因此，當(dāng)一個(gè)零件不再履行(執(zhí)行)其所需的功能時(shí)，它就失效（即使它沒有物理損壞）。有時(shí)故障可能是由于磨損而改變了匹配(配合)部件的正確位置。27FailureAnalysisandDimensionalDeterminationThewearmaybeduetoabnormal[?b?n?:rml]

frictionorvibrationbetweentwomatingparts.Failurealsomaybeduetoaphenomenoncalledcreep,whichistheplasticflowofamaterialunderloadatelevated[??l??vet?d]temperatures.磨損可能是由于兩個(gè)零件之間的摩擦或振動(dòng)異常引起的。故障也可能是由于蠕變現(xiàn)象，即材料在負(fù)載及(提)

高溫下的塑性流動(dòng)。28FailureAnalysisandDimensionalDeterminationInaddition,theactualshapeofapartmayberesponsible[r??spɑ:ns?bl]forfailure.Forexample,stressconcentrationsduetosuddenchangesincontour[?kɑ:nt?r]

mustbetakenintoaccount.此外，零件的實(shí)際形狀可能要對(duì)失敗負(fù)有責(zé)任的。例如，