《材料力學(xué)性能》中英文全套PPT課件

《材料力學(xué)性能》中英文全套PPT課件,材料力學(xué)性能,材料,力學(xué)性能,中英文,全套,PPT,課件 MechanicalTestsStaticTestsProperties:Elasticity,yield,plasticity,fracture,toughness,etc.性質(zhì)：彈性，屈服力，塑性，斷裂，硬度等Load:tension,compression,bending,torsion,etc.加載力：拉力，壓力，彎曲，剪切等Coefficientofsoftnessofstressstate:=max/max應(yīng)力狀態(tài)的柔性系數(shù)：=max/maxTensiontests:Engineeringstress/conditionalstress;Engineeringstrain/conditionalstrain.拉力實驗：工程應(yīng)力；工程應(yīng)變.Engineeringstress/Engineeringstrain工程應(yīng)力/應(yīng)變Engineeringstress/conditionalstress:Theinstantaneousloadappliedtoaspecimendividedbyitscross-sectionalareabeforeanydeformation.工程應(yīng)力：瞬時載荷除以變形前的截面積大小。Engineeringstrain/conditionalstrain:Thechangeingaugelengthofaspecimen(inthedirectionofanappliedstress)dividedbyitsoriginalgaugelength.工程應(yīng)變：試樣標(biāo)距長度的變化（加載力方向上）除以原始標(biāo)距長度。Standardtensilespecimen標(biāo)準(zhǔn)拉伸試樣Stress-strainbehaviorofelasticdeformation彈性變形的應(yīng)力應(yīng)變圖Yieldingandyieldstrength屈服現(xiàn)象和屈服力Yielding:Theonsetofplasticdeformation.屈服：塑性變形的開始Yieldstrengthy:Thestressrequiredtoproduceaveryslightyetspecifiedamountofplasticstrain;astrainoffsetof0.002iscommonlyused.屈服極限應(yīng)力y：造成微量塑性變形所需的應(yīng)力，一般取0.002的應(yīng)變偏移量。Proportionallimit:thepointonastress-straincurveatwhichthestraightlineproportionalitybetweenstressandstrainceases.比例極限：應(yīng)力應(yīng)變曲線中應(yīng)力和應(yīng)變直線比例中正的地方。Tensilestrength拉力Tensile(ultimate)strength(TS):Themaximumengineeringstress,intension,thatmaybesustainedwithoutfracture.最大拉應(yīng)力（TS）：拉伸時，能持續(xù)而不發(fā)生斷裂的最大的工程應(yīng)力。Ductility延性DuctilityAmeasureofamaterialsabilitytoundergoappreciableplasticdeformationbeforefracture;itmaybeexpressedaspercentelongation(%EL)orpercentreductioninarea(%RA)fromatensiletest.材料在斷裂前發(fā)生塑性變形大小的度量。用拉伸試驗中的長度增加百分比(%EL)或面積減小百分比(%RA)來衡量。Stress-straincurvesofbrittleandductilematerials脆性和塑性材料的應(yīng)力應(yīng)變曲線Engineeringstress-strainbehaviorforironatthreetemperatures鐵在三種不同溫度下的工程應(yīng)力應(yīng)變曲線Truestressandstrain真實應(yīng)力與真實應(yīng)變Truestress:Theinstantaneousappliedloaddividedbytheinstantaneouscross-sectionalareaofaspecimen.真實應(yīng)力：瞬時載荷除以該時刻的瞬時截面積。Truestrain:Thenaturallogarithmoftheratioofinstantaneousgaugelengthtooriginalgaugelengthofaspecimenbeingdeformedbyauniaxialforce.真實應(yīng)變：由軸向拉力而變形的瞬時標(biāo)距長度與其原始標(biāo)距長度的自然對數(shù)。Ifnovolumechangeoccursduringdeformation若變形中無體積變化，則：Onlyvalidtotheonsetofnecking僅適用于頸縮開始前Typicaltensileengineeringstress-strainandtruestress-strainbehaviors典型的工程應(yīng)力應(yīng)變圖和真實應(yīng)力應(yīng)變圖Strain-hardeningexponent應(yīng)變硬化指數(shù)Fromtheonsetofplasticdeformationtothepointatwhichneckingbegins從塑性變形開始到頸縮開始前：Elasticrecoveryduringplasticdeformation塑性變形中的彈性回復(fù)Definitionsofandrelationshipsbetweentrueandengineeringstressandstrain真實/工程應(yīng)力應(yīng)變間的關(guān)系Stress-strainbehaviorofpolymers高分子聚合物中的應(yīng)力應(yīng)變圖Abrittle脆性Bplastic塑性C-highlyelasticpolymers高彈性Yieldandtensilestrengths屈服力和最大拉力Theinfluenceoftemperatureonthestress-straincharacteristicsofpolymethylmethacrylate溫度對聚甲基丙烯酸酯的應(yīng)力應(yīng)變的影響Schematictensilestress-straincurveforasemicrystallinepolymer半晶體聚合物的拉伸應(yīng)力應(yīng)變曲線problemAcylindricalspecimenofsteelhavinganoriginaldiameterof12.8mmistensiletestedtofracturedandfoundtohaveanengineeringfracturestrengthof460MPa.Ifitscross-sectionaldiameteratfractureis10.7mm,determine:(a)Theductilityintermsofpercentreductioninarea.(b)Thetruestressatfracture一個圓柱體鋼試樣，其初始直徑為12.8mm。受拉到斷裂，其斷裂的工程應(yīng)力為460MPa。若其斷裂時截面積為10.7mm，試確定：通過面積減小百分比計算的延展性及斷裂時的真實應(yīng)力。Graphicaldeterminationofproportionallimit圖像決定的比例極限D(zhuǎn)eterminationoftheyieldlimit確定屈服極限D(zhuǎn)eterminationofrelativeelongation相對拉伸長度的確定ProblemInthetensiletest,ifaspecimenrupturednearoneendinsteadofinthemiddleofthegaugelength,howtodetermineitsrelativeelongation?在一個拉伸實驗中，若試樣在一端斷裂而不是在中間斷裂，怎樣決定它的相對伸長量。ProblemAcylindricalrodof380mmlonghavingadiameterof10.0mm,istobesubjectedtoatensileload.Iftheloadistoexperienceneitherplasticdeformationnoranelongationofmorethan0.9mmwhentheappliedloadis24500N,whichofthefourmetalsoralloysarepossiblecandidates?Justifyyourchoice(s).一個長度為380mm的圓柱桿直徑為10mm受拉伸載荷。當(dāng)加載載荷為24500N時，它并未發(fā)生塑性變形且其伸長長度不超過0.9mm。下面四種金屬或合金中哪一種可能是該材料的組成成分？請做出選擇。Hardnesstests硬度測試Hardness:Themeasureofamaterialsresistancetodeformationbysurfaceindentationorbyabrasion.硬度：金屬抗受載或磨損變形的能力。Theeasiestandmostpopularmethodofmechanicaltestsofmaterials.是最簡單最普通的測量材料力學(xué)的實驗Researchstudiesandcontrolmeansinindustry.是工業(yè)上研究上控制的方法。Widelyusedinmanufacturingpracticefortheeaseandquicknessofmeasurement.是廣泛應(yīng)用的最簡單、最迅捷的測量方法。Hardnesstestsareperformedmorefrequentlythananyothermechanicaltestforseveralreasons:硬度測試比其它測試更常用的原因：Theyaresimpleandinexpensive;簡單便宜Thetestisnondestructive;對材料無損傷；Othermechanicalpropertiesoftenmaybeestimatedfromhardnessdata.其它力學(xué)性能通?？蓮挠捕葦?shù)據(jù)中推測出來。Thereaumurhardnesstest列式溫標(biāo)的硬度測試Atthebeginningof18thcentury;Trihedralprism三面體棱鏡Mohshardness莫氏硬度Atthebeginningof19thcentury;Ahardnessscaleforminerals,stillusedinmineralogy;金屬硬度范圍，仍用于礦物中Arranged10mineralsintoarowaccordingtotheirabilitytoscratchthesurfaceofotherminerals:將十種金屬根據(jù)它們在材料上刻痕的能力分成一組10Diamond9Corundum8Topaz7Quartz6Orthoclase5Apatite4Fluorite3Calcite2Gypsum1TalcQuantitativehardnesstechniques硬度量度技術(shù)Asmallindenterisforcedintothesurfaceofamaterialtobetested,undercontrolledconditionsandofloadandrateofapplication.在規(guī)格條件、載荷和加載速率下，在材料表面形成一個微小的刻痕。Thedepthorsizeofindentationismeasured,whichinturnisrelatedtoahardnessnumber.刻痕的深度和大小被測量出來，并轉(zhuǎn)化成硬度指數(shù)。Rockwell,Brinell,KnoopandVickershardnesstests.Hardnesstestingtechniques硬度測試技術(shù)RockwellhardnesstestsIndentersincludesphericalandhardenedsteelballshavingdiametersof1/16,1/8,1/4,andin.,andaconicaldiamondindenter,whichisusedforthehardestmaterials.壓頭包手球狀的直徑為1/16,1/8,1/4和英寸的硬化鋼，一個圓錐形的剛玉壓頭用于測量最硬的材料。RockwellhardnessscalesandSuperficial表層Rockwellhardnessscales.HRA,HRB,HRCHR15N,HR30NRockwellhardnessscales硬度范圍SuperficialRockwellhardnessscales表層Rockwell硬度范圍Foreachscale,hardnessmayrangeupto130;however,ashardnessvaluesriseabove100ordropbellow20onanyscale,theybecameinaccurate.在每個范圍中，硬度可能達到130。但當(dāng)硬度達到100以上或20以下時，它們就變得不準(zhǔn)確了。Inaccuraciesalsoresultifthetestspecimenistoothin,ifanindentationismadetoonearaspecimenedge,oriftwoindentationsaremadetooclosetooneanother.Specimenthicknessshouldbeatleasttentimestheindentationdepth,whereasallowanceshouldbemadeforatleastthreeindentationdiametersbetweenthecenteroneindentationandthespecimenedge,ortothecenterofasecondindentation.試樣太薄，壓痕太靠近試樣邊緣，或兩個壓痕挨的太近，都會導(dǎo)致測量的不準(zhǔn)確性。試樣厚度應(yīng)該至少為壓痕深度的10倍，且兩個壓痕中心到邊緣距離和兩壓痕中心間距應(yīng)該為其壓痕直徑的3倍以上。Furthermore,testingofspecimensstackedoneontopofanotherisnotrecommended.Also,accuracyisdependentontheindentationbeingmadeintoasmoothflatsurface.另外，測量試樣不要彼此堆疊。并且，精度與平滑表面的刻痕有關(guān)。Brinellhardnesstest布氏硬度Thediameterofthehardenedsteel(ortungstencarbide)indenteris10.00mm.硬質(zhì)鋼（鎢碳鋼）壓頭的直徑為10.00mm。Standardloadsrangebetween500and3000kgin500-kgincrements;標(biāo)準(zhǔn)載荷范圍5003000kg，以500kg速度遞增Duringatest,theloadismaintainedconstantforaspecifiedtime(between10and30s).測試中載荷在特定時間（1030s）內(nèi)保持不變。Minimumspecimenthicknessaswellasindentationposition(relativetospecimenedges)andminimumindentationspacingrequirementsarethesameasforRockwelltests.Inaddition,awell-definedindentationisrequired;thisnecessitatesasmoothflatsurfaceinwhichtheindentationismade.HB試樣的最小厚度，壓痕距試樣邊緣的位置和壓痕間的最小間距與Rockwell硬度測試相同。另外，一個標(biāo)準(zhǔn)的壓痕也同樣重要：它需要一個平滑的平面。單位：HBKnoopandVickersmicrohardnesstestsKnoopandVickers微觀硬度測試Foreachtestaverysmalldiamondindenterhavingpyramidgeometryisforcedintothesurfaceofthespecimen.每次實驗時，一個細小的三角形鉆石壓頭壓入試樣表面。AppliedloadsaremuchsmallerthanforRockwellandBrinell,rangebetween1and1000g.外加載荷（11000g）比Rockwell和Brinell測試小得多Theresultingimpressionisobservedunderamicroscopeandmeasured;thismeasurementisthenconvertedintoahardnessnumber.壓痕在顯微鏡下觀察測量，并轉(zhuǎn)化成相應(yīng)的硬度系數(shù)Carefulspecimensurfacepreparation(grindingandpolishing)maybenecessarytoensureawell-definedindentationthatmaybeaccuratelymeasured.為了精確測量一個良好有效的壓痕，試樣表面必需有所準(zhǔn)備（摩和擦）。TheKnoopandVickersarehardnessnumbersaredesignatedbyHKandHV,respectively,andhardnessscalesforbothtechniquesareapproximatelyequivalent.Knoop和Vickers硬度測試值分別由HK和HV表示，相應(yīng)地，兩種測量得到的硬度范圍是近似等效的。KnoopandVickersarereferredtoasmicrohardnesstestingmethodsonthebasisofloadandindentersize.Knoop和Vickers是根據(jù)載荷和壓頭大小的微觀硬度測量的方法。Hardnessconversion硬度轉(zhuǎn)化Correlationbetweenhardnessandtensilestrength硬度和拉力之間的關(guān)系A(chǔ)saruleofthumbformoststeels,theHBandthetensilestrengtharerelatedaccordingto對大多數(shù)鋼種而言，HB和最大拉應(yīng)力間的關(guān)系如下：Compressivetest壓縮實驗Compressionofcylindricaltestpiecesisoneofthesoftestmethod.壓縮圓柱體實驗是一種最常用的方法。Coefficientofsoftnessofstressstate:=max/max=2.應(yīng)力狀態(tài)軟性系數(shù)：=max/max=2Suitabletotestbrittlematerials.只適合于脆性材料。Testpiecepreparedforcompression壓縮實驗件1-lowersupport下支撐點2-uppersphericalsupport上球支撐點3movablecross-pieceofthemachine可移動及其部件4-testpiece試驗件Compressioncurves壓縮實驗曲線Conditionalandactualcompressiondiagramsofcopper銅的條件/真實應(yīng)力壓縮圖Ductility(intensiletest)張力測試中的延性Ductility延性percentelongation(%EL)orpercentreductioninarea(%RA)fromatensiletest.伸張實驗中的長度或面積變化百分比。Percentcontractionorpercentexpansioninareafromacompressivetest.壓縮測試中的長度或面積變化百分比。TorsionalTests扭轉(zhuǎn)實驗Fractureoftestpiecesintorsion試樣因扭轉(zhuǎn)而發(fā)生的斷裂Torsionaldiagram扭轉(zhuǎn)轉(zhuǎn)矩角度圖DetermineshearmodulusG剪切模量GValidintheelasticregion;彈性階段有效M-thetorque,kgf.m;轉(zhuǎn)矩l0-thegaugelength,mm;標(biāo)距-twistangleatthelengthl0,rad;扭轉(zhuǎn)角d0-the cross-sectional diameter,mm.截面直徑Determinethehighestrelativeshear最高相對剪切max=1-21and2aretheangularindicesattheendsofthegaugelength,rad;1和2是標(biāo)距末端的角度指數(shù)Conditional(engineering)strength條件（工程）應(yīng)力Proportionallimitpr;比例極限Yieldlimit0.3;屈服極限Conditionalultimatestrengthu.最大工程應(yīng)力Actual(true)ultimatestrength最大真實應(yīng)力Testsofpieceswithstressconcentrators有應(yīng)力集中的實驗件Stressconcentrationcoefficientac應(yīng)力集中系數(shù)acmaxisthemaximumaxialstress;max是最大軸向應(yīng)力isthenominaloraveragestressinthenotchsection在刻痕處的平均應(yīng)力（名義應(yīng)力）cisindependentofmaterialsproperties.c獨立于材料的性質(zhì)Stressdistributionofalargeplate大平面上的應(yīng)力分布Stressdistributionfornotchedcylindricalsamples(elastic)圓柱體刻痕處彈性階段的應(yīng)力分布Stressdistributionfornotchedcylindricalsamples(elastic-plastic)圓柱體刻痕處在彈性到塑性階段上的應(yīng)力分布Fractograph(1)斷口組織Fractograph(2)NotchSensitivityRatio(NSR)刻痕敏感系數(shù)Bendingtests/Flexuralstrength彎曲實驗/撓度強度a-concentratedbendingb-purebendingMaximumstresses最大應(yīng)力(a)(b)Three-pointbending,ASTMStandardc1161三點彎曲Flexuralstrength,bendingstrength,transverserupturestrength抗彎強度，彎曲強度，橫向斷裂強度Forarectangularcrosssection當(dāng)截面積為矩形時：Foracircularcrosssection當(dāng)截面積為圓形時Typicalbendingdiagramsaplasticmaterial塑性材料b-intermediatecase中間情況cbrittlematerial脆性材料Impacttestingtechniques撞擊實驗技術(shù)Charpyimpacttest沙爾皮沖擊實驗機Charpyimpacttest沙爾皮沖擊實驗Impacttoughness(k):沖擊強度(k)k=mg(h-h)/A0Variablesincludingspecimensizeandshapeaswellasnotchconfigurationanddepthinfluencetheresults.其中的變化包括試樣的大小和形狀，洞的特征和深度對結(jié)果也有影響TheCharpyv-notch(CVN)techniqueismostcommonlyused.沙爾皮沖擊(CVN)實驗技術(shù)仍被廣泛應(yīng)用。Ductile-to-brittletransition塑性到脆性的轉(zhuǎn)變Appearanceofthefailuresurfaceisindicativeofthenatureoffracture,andmaybeusedintransitiontemperaturedeterminations.Forductilefracturethissurfaceappearsfibrousordull(orofshearcharacter);conversely,totalbrittlesurfacehaveagranular(shiny)texture(orcleavagecharacter).Overtheductile-to-brittletransition,featuresofbothtypeswillexist.失效表面的出現(xiàn)是斷裂本質(zhì)的一種預(yù)兆，可以被應(yīng)用在轉(zhuǎn)變溫度的確定上。塑性斷裂表面是纖維狀和灰暗的。相反，脆性斷裂表面有晶體織構(gòu)（解理特征）。在塑性脆性轉(zhuǎn)變中，兩個特征都可能存在。NTD:NilDuctilitytemperature;無塑性轉(zhuǎn)變溫度50%FATT(FractureAppearanceTransitionTemperature):結(jié)晶區(qū)面積占整個斷面面積50%時的溫度叫做50%斷裂形貌(外觀）轉(zhuǎn)變溫度。DBTT:Ductile-to-BrittleTransitionTemperature.Notallmetalalloysdisplayaductile-to-brittletransition.FCCmetalsremainductileevenatextremelylowtemperatures.However,BCCandHCPalloysexperiencethistransition.Forthesematerialsthetransitiontemperatureissensitivetobothalloycompositionandmicrostructure.并不是所有的金屬都有一個塑性到脆性的轉(zhuǎn)變。面心立方結(jié)構(gòu)金屬合金在低溫下仍是塑性的。但體心立方和密排六方合金有這種轉(zhuǎn)變。合金成分和微觀結(jié)構(gòu)都對轉(zhuǎn)變溫度有明顯影響。InfluenceofcarboncontentontheCVNenergy-versus-temperaturebehaviorforsteel鋼中碳含量對CVN溫度能量變化的影響Problem1st1.1 A cylindrical specimen of aluminumhavingadiameterof12.8mmandagaugelengthof50.80mmispulledintension.Usetheload-elongationcharacteristicstabulatedbellowtocompeteproblemsathroughe.一個直徑為12.8mm，標(biāo)距為50.80mm的鋁圓柱體試樣受拉應(yīng)力作用。用下表中的載荷伸長特征，完成a到e的問題。(a)Plot the data as engineering stress versus engineeringstrain.在圖表上作出工程應(yīng)力應(yīng)變圖(b)Computethemodulusofelasticity.算彈性模量(c)Determine the yield strength at a strainoffsetof0.002.當(dāng)應(yīng)變?yōu)?.002時計算屈服應(yīng)力(d)Determinethetensilestrengthofthisalloy.計算合金的拉應(yīng)力(e)Whattheapproximateductility,inpercentelongation?算出相應(yīng)的延展性，由長度百分比表示。A0=128.6mm2E=179.5/0.00299MPa=60GPaTS=369MPa屈服強度277MPa%EL=(59.182-50.8)/50.8*100=16.5%Problem2nd1.2Thefollowingtruestressesproducethecorrespondingtrueplasticstrainsforabrassalloy:黃銅的真實應(yīng)力，真實應(yīng)變Whattruestressisnecessarytoproduceatrueplasticstrainof0.25?為了形成一個0.25的真實塑性應(yīng)變，需多大的真實應(yīng)力？1.2Strain-hardeningexponent應(yīng)變強化的解釋K=630.957n=0.262=439MPaProblem3rd1.3 Consider a steel plate having a through-thicknessedgecracksimilartothatshownbellow;theplatewidth(W)is1000mm,anditsthicknessis 12mm.Furthermore,plane strain fracturetoughnessandyieldstrengthofthismaterialare80MPam1/2 and 1200MPa,If the plate is to beloadedtoastressof300MPa,wouldyouexpectfailuretooccuriftheonehalfcracklengthais15mm?Whyornot?一個平面鋼具有一個橫貫厚度的裂紋如下圖所示：平面鋼的寬度為1000mm，厚度為12mm。另外，斷裂時平面應(yīng)變硬度和屈服強度分別為80MPam1/2和1200MPa，當(dāng)裂紋長度的一半a達到15mm時會斷裂嗎？為什么？1.3Stressintensitycoefficient(K)應(yīng)力強度系數(shù)Problem4th1.4TabulatedbellowaredatathatweregatheredfromaseriesofCharpyimpacttestsonaductilecastiron:(a)Plot the data as impact energy versustemperature.(b)Determinetheductile-to-brittletemperatureasthattemperaturecorrespondingtotheaverageofthemaximumandminimumimpactenergies.(c)Determinetheductile-to-brittletemperatureasthattemperatureatwhichtheimpactenergyis80J.下表中列出了球墨鑄鐵在一系列沙爾皮沖擊實驗中的數(shù)據(jù)：a.作圖標(biāo)出沖擊能量和溫度b.確定對應(yīng)于最大和最小沖擊能量的平均值的塑性-脆性溫度c.確定沖擊能量為80J時塑性-脆性圖中的溫度