CAESARII官方培訓(xùn)講義(共67張)

CAESARII管道應(yīng)力分析培訓(xùn)王大輝北京艾思弗軟件公司2023/1/9BasicStressTheory&2023/1/9BasicStressTheory&介紹培訓(xùn)的目的在于讓您了解和掌握應(yīng)力分析的基礎(chǔ)概念模型和邊界條件的建立結(jié)果的分析和評(píng)判往復(fù)壓縮機(jī)的分析專(zhuān)題日常遇到的問(wèn)題和解決方法2023/1/9BasicStressTheory&介紹3D梁?jiǎn)卧奶卣鳠o(wú)限細(xì)的桿單元全部行為靠端點(diǎn)位移決定彎曲變形是主要的2023/1/9BasicStressTheory&介紹3DBeamElementCharacteristics3D梁?jiǎn)卧奶卣鲀H說(shuō)明整體行為無(wú)局部作用（表面沒(méi)有碰撞）忽略二次影響（小轉(zhuǎn)動(dòng)）遵循胡克定律2023/1/9BasicStressTheory&StressBasics應(yīng)力基礎(chǔ) 局部坐標(biāo)系下管道應(yīng)力分類(lèi)（引發(fā)應(yīng)力的載荷）軸向應(yīng)力LongitudinalStress-SL環(huán)向應(yīng)力HoopStress-SH徑向應(yīng)力RadialStress-SR剪切應(yīng)力ShearStress-2023/1/9BasicStressTheory&軸向應(yīng)力沿管道軸向Alongaxisofpipe軸向力引起AxialForce軸向力/面積(F/A)內(nèi)壓引起PressurePd/4torP*di/(do2-di2)彎矩引起B(yǎng)endingMomentMc/I最大應(yīng)力環(huán)向的外表面某點(diǎn)處

I/radiusZ(截面模量);useM/Z2023/1/9BasicStressTheory&壓力引起的環(huán)向應(yīng)力環(huán)向（垂直于半徑）

Pd/2t和壁厚緊密相關(guān)環(huán)向應(yīng)力十分重要，但規(guī)范應(yīng)力不考慮它。Hoopisveryimportant,itsjustnotpartofthe“codestress”環(huán)向應(yīng)力用來(lái)確定壁厚：依據(jù)直徑、許用應(yīng)力、腐蝕裕量、加工偏差、壓力確定管道壁厚。2023/1/9BasicStressTheory&壓力引發(fā)的徑向應(yīng)力沿半徑方向向內(nèi)內(nèi)壁的徑向應(yīng)力大小是：-P外壁的徑向應(yīng)力大小為0最大彎曲應(yīng)力發(fā)生在管道的外表面，故該項(xiàng)忽略2023/1/9BasicStressTheory&剪切應(yīng)力ShearStresses平面內(nèi)垂直半徑ShearForce剪力在外表面剪力很小，應(yīng)力計(jì)算忽略支架設(shè)計(jì)有時(shí)需要考慮Torque扭矩最大應(yīng)力在外表面

MT/2Z2023/1/9BasicStressTheory&3-D應(yīng)力評(píng)定Aloaded,3-Dpipecontainsarepresentativeinfinitesimalstresscubeaddgraphic(Fig1-13)Thisstresscubeisinequilibriumandcanberotatedinspaceaddgraphic(rotatedcubewithloads)Thiscubecanberotatedsothatshearstressesarezero.ThisresultsinthePrincipalStresses.2023/1/9BasicStressTheory&Simplifyingtoa2-DStressThisplanecanberotatedtoeithereliminateormaximizeshearstressbyusingMohr’sCircle:Sinceweusetheoutsidesurfacewhereradialstressiszero;let’smovetoaplaneelement:2023/1/9BasicStressTheory&UsingMohr’sCircleCutthesquareattocalculateS1Cutthesquareat+90tocalculateS2Cutthesquareat+45tocalculatemax2023/1/9BasicStressTheory&UsingMohr’sCircleBrittlematerial(failurebyfracture)-maxprincipalstressDuctilematerial(failurebygeneralyielding)-maxprincipalstressisusedtosetwallthicknessMaximumshearstressisagoodpredictionanderrsontheconservativesideseep84&85ofAdv.Mech.OfMat’ls2023/1/9BasicStressTheory&基本應(yīng)力“CodeStress規(guī)范應(yīng)力”應(yīng)力評(píng)定Evaluatinga3-DStressS=F/A+Pd/4t+M/Z軸向力、軸向壓力，軸向彎矩一起的分量加和規(guī)范不同，上面的算式也不同那些應(yīng)力沒(méi)有包含進(jìn)來(lái)？2023/1/9BasicStressTheory&基本應(yīng)力“CodeStress規(guī)范應(yīng)力”幾個(gè)實(shí)效理論AFewFailureTheories變形能或八面體剪切應(yīng)力(根據(jù)米賽斯理論和其它的理論）。最大剪應(yīng)力理論

（Columb理論）

。大多數(shù)理論都根據(jù)這個(gè)理論。由于剪切影響而限制最大主應(yīng)力(Rankine理論)。CAESARII132列輸出應(yīng)力報(bào)告中顯示了米賽斯或最大剪應(yīng)力強(qiáng)度理論。應(yīng)力報(bào)告由configuration設(shè)置來(lái)決定。2023/1/9BasicStressTheory&基本應(yīng)力“CodeStress規(guī)范應(yīng)力”基于最大剪應(yīng)力實(shí)效理論，ASME規(guī)范委員會(huì)頒布了規(guī)范應(yīng)力方程Basedonthemaximumshearfailuretheory,theCodeCommitteedevelopedthe“codeequations”目的在于避免管道系統(tǒng)實(shí)效Purposewastoreducesystemfailures這種解決辦法很實(shí)用，但仍然有問(wèn)題存在Thisapproachworkedwell,buttherewerestillproblems,evenaslateaspostWorldWarII.研究表明直管道比較符合理論Studiesshowedsystemsofstraightpipematchedtheory研究表明元件失效比理論發(fā)生的早Studiesshowedsystemswithfittingsfailedearlierthantheorypredicted.ASME規(guī)范委員會(huì)委托Markl來(lái)研究這個(gè)問(wèn)題CodeCommitteecommissionedMarkltostudythis...2023/1/9BasicStressTheory&基本應(yīng)力“CodeStress規(guī)范應(yīng)力”Markl’s試驗(yàn)和結(jié)果將試驗(yàn)用的管道充滿水，按某個(gè)方向和位移反復(fù)搖晃管道。Testconfigurationsfilledwithwaterandcycledthroughapredetermineddisplacement預(yù)測(cè)失效循環(huán)次數(shù)Theoryshouldbeabletopredict“cyclestofailure”發(fā)現(xiàn)最先失效的管件及其原因Fittingscausedearlyfailure…because…對(duì)管件引入應(yīng)力集中Stressesconcentrationsareintroducedbyfittings分析試驗(yàn)數(shù)據(jù)，修正軸向應(yīng)力彎曲項(xiàng)Testdataanalyzedandamodificationtothebendingtermofthecodestressequationwasintroduced:Sbending=iM/z2023/1/9BasicStressTheory&基本應(yīng)力“CodeStress規(guī)范應(yīng)力”Markl’s試驗(yàn)和結(jié)果應(yīng)力增強(qiáng)系數(shù)i和元件的形式有關(guān)對(duì)于彎頭“i”的計(jì)算需要如下:我們需要彎頭的幾何參數(shù)計(jì)算彎頭柔性“h”計(jì)算應(yīng)力增大系數(shù)StressIntensificationFactor“i”,石化規(guī)范對(duì)平面內(nèi)、外的SIF取值不同，電力取相同的sif2023/1/9BasicStressTheory&基本應(yīng)力“CodeStress規(guī)范應(yīng)力”Markl’s試驗(yàn)和結(jié)果Aload“intheplane”ofthefittingcauses“in-plane”bending平面內(nèi)Aload“outoftheplane”ofthefittingcauses“out-of-plane”bending平面外2023/1/9BasicStressTheory&基本應(yīng)力“CodeStress規(guī)范應(yīng)力”Markl’s試驗(yàn)和結(jié)果規(guī)范上的附注十分重要PetroChemcodesmodifySIF(andflexibilityfactor)basedonpressurestiffeninginanote石化規(guī)范規(guī)定壓力硬化影響ＳＩＦ和柔性系數(shù)應(yīng)力算式變化如下 S=F/A+Pd/4t+iM/z應(yīng)力增大系數(shù)不能小于１2023/1/9BasicStressTheory&Basisfor“CodeStressEquations”Markl’s試驗(yàn)和結(jié)果TheSIFisa“fudge”factor

SIF是個(gè)近似的參數(shù)TheSIFattemptstoincreasethebendingstresscomputedatthenodepoint,tomatchtheactualhigherstressduetothestressconcentrationcausedbythefitting.引入SIF在于改變特殊管件應(yīng)力集中，讓他們的應(yīng)力根實(shí)際大小更接近。Marklonlytested4x4Stdfittings!!!但Markl僅測(cè)試了４ｘ４AdditionalworkisstillbeingdonetodayinthefieldofSIFs.Resultsarepublishedin:PVP,WRC,JournalofPressureVesselTechnology.其余的工作人們?nèi)匀辉诶^續(xù)進(jìn)行。2023/1/9BasicStressTheory&規(guī)范效驗(yàn)的工況兩種失效：Primaryfailure一次失效Secondaryfailure二次失效(AthirdfailuremodeaddressedisOccasional,whichissimilartoPrimary.)2023/1/9BasicStressTheory&規(guī)范效驗(yàn)的工況PrimaryFailureCase一次失效力的作用ForceDriven非自限性NotSelf-Limiting重量、壓力、集中力Weight,Pressure,

ConcentratedForces2023/1/9BasicStressTheory&規(guī)范效驗(yàn)的工況PrimaryFailureCase一次失效力的作用ForceDriven非自限性NotSelf-Limiting重量、壓力、集中力,Weight、Pressure,

ConcentratedForces2023/1/9BasicStressTheory&規(guī)范效驗(yàn)的工況SecondaryFailureCase二次失效位移作用DisplacementDriven自限性IsSelf-Limiting溫度、位移和其他變化載荷引起的Temperature,Displacement,plusothervaryingloads-i.e.weight2023/1/9BasicStressTheory&規(guī)范效驗(yàn)的工況

(1)=W+T1+P1(OPE)(2)=W+P1(SUS)(3)=DS1-DS2(EXP)Operatingcase,usedfor:熱態(tài)restraint&equipmentloads推力和彎矩maximumdisplacements最大位移computationofEXPcase計(jì)算二次應(yīng)力SustainedcaseforPRIMARYloadsandstresscompliance計(jì)算一次應(yīng)力Expansioncasefor“extremedisplacementstressrange”膨脹工況，計(jì)算二次應(yīng)力displacementsforcase3aredisplacementsfromcase1minusdisplacementsfromcase22023/1/9BasicStressTheory&規(guī)范效驗(yàn)的工況膨脹工況的解釋ExpansionCaseExplainedWhatdoes“DS1-DS2(EXP)”mean?Isaloadcasewith“T1(EXP)thesamething?2023/1/9BasicStressTheory&LoadCasesforCodeCompliance膨脹工況的解釋ExpansionCaseExplainedThecodestatesthattheexpansionstressesaretobecomputedfromthe"extremedisplacementstressrange".Theseareallveryimportantwords.Considertheirmeaning…EXTREME極端:Inthissenseitmeansthemost,orthelargest.RANGE范圍:Typicallyadifference.Whatdifference?Thedifferencebetweentheextremes.Whatextremes?DISPLACEMENT位移:Thisdefineswhatextremestotakethedifferenceof.STRESS應(yīng)力:Whatweareeventuallyafter.2023/1/9BasicStressTheory&LoadCasesforCodeCompliance膨脹工況的解釋ExpansionCaseExplainedPuttingeverythingbacktogether,wearetoldtocomputestressesfromtheextremedisplacementrange.Howcanwedothis?計(jì)算最大位移范圍的應(yīng)力Considertheequationbeingsolved;[K]{x}={f}.Inthisequation,weknow[K]and{f},andwearesolvingfor{x},thedisplacementvector.InCAESARII,whenwesetupanexpansioncase,wedefineitas"DS1-DS2",wherethe"1"and"2"refertothedisplacementvector({x})ofloadcases1and2respectively.2023/1/9BasicStressTheory&LoadCasesforCodeCompliance膨脹工況的解釋ExpansionCaseExplained(Obviouslytheloadcasenumbersaresubjecttochangeonajobbyjobbasis.)Whatdoyougetwhenyoutake"DS1-DS2"?Well{x1}-{x2}yields{x'},apseudodisplacementvector.{x'}isnotarealsetofdisplacementsthatyoucangooutandmeasurewitharuler,ratheritisthedifferencebetweentwopositionsofthepipe.Oncewehave{x'},wecanusethesameroutinesusedintheOPEorSUScasestocomputeelementforces,andfinallyelementstresses.2023/1/9BasicStressTheory&LoadCasesforCodeCompliance膨脹工況的解釋ExpansionCaseExplainedHowever,theseelementforcesarealsopseudoforces,i.ethedifferenceinforcesbetweentwopositionsofthepipe.力的大小是兩個(gè)工況力的差值Similarly,thestressescomputedarenotrealstresses,butstressdifferences.應(yīng)力不是真實(shí)應(yīng)力，是應(yīng)力的差值Thisisexactlywhatthecodewants,thestressdifference,whichwascomputedfromadisplacementrange.二次應(yīng)力是位移變化量導(dǎo)致的Astowhetherornotthisstressdifferenceistheextreme,wellthatdependsonthejob.2023/1/9BasicStressTheory&LoadCasesforCodeCompliance膨脹工況的解釋ExpansionCaseExplainedDS1-DS2和T1“一樣嗎？.有可能.如果是線性系統(tǒng)，答案是一樣的。如果是非線性系統(tǒng)(如你有+Ys,orgaps,orfriction),答案是不一樣的。原因是兩個(gè)工況應(yīng)用[K]{x}={f}。Thereasonforthiscanbefoundbyexaminingtheequation[K]{x}={f}forthetwodifferentmethods.2023/1/9BasicStressTheory&LoadCasesforCodeComplianceExpansionCaseExplainedForthisdiscussion,rearrangetheequationto{x}={f}/[K],whereweknowwedon'treallydivideby[K],wemultiplybyitsinverse.OPE:{xope}={fope}/[Kope]={W+T1+P1}/[Kope]SUS:{xsus}={fsus}/[Ksus]={W+P1}/[Ksus]EXP:{xexp}={xope}-{xsus}={W+T1+P1}/[Kope] -{W+P1}/[Ksus]Canwesimplifytheaboveequationasfollows? EXP:{xexp}={W+T1+P1}/[K]-{W+P1}/[K}2023/1/9BasicStressTheory&LoadCasesforCodeCompliance膨脹工況解釋ExpansionCaseExplainedCanwesimplifytheaboveequationasfollows? EXP:{xexp}={W+T1+P1}/[K]-{W+P1}/[K]Cancelingliketerms(theonesinred)yields: {xexp}={T1}/[K]問(wèn)題在于[Kope]和[Ksus]是否相等.線性系統(tǒng)相等.非線性系統(tǒng)不相等2023/1/9BasicStressTheory&LoadCasesforCodeCompliance膨脹工況解釋ExpansionCaseExplained如果一個(gè)系統(tǒng)有兩個(gè)操作溫度。Anotherproofthatthe"DS1-DS2"methodisthecorrectwaytogoistoconsiderajobwithtwooperatingtemperatures,oneaboveambientandonebelowambient.如T1=+300,andT2=-50.CAESARII軟件自動(dòng)建立如下工況:(1)W+T1+P1(OPE)(2)W+T2+P1(OPE)(3)W+P1(SUS)(4)DS1-DS3(EXP)(5)DS2-DS3(EXP)2023/1/9BasicStressTheory&LoadCasesforCodeCompliance膨脹工況解釋ExpansionCaseExplained上述工況正確，但沒(méi)能說(shuō)明規(guī)范要求的最大應(yīng)力范圍因?yàn)镃II并不能判斷荷載所代表的具體含義為滿足規(guī)范的要求，用戶必須自己定義:(6)DS1-DS2(EXP)這個(gè)工況是最大位移膨脹應(yīng)力，正是規(guī)范所要求的。您根本不能考慮使用T1來(lái)計(jì)算膨脹應(yīng)力.2023/1/9BasicStressTheory&LoadCasesforCodeComplianceExpansionCaseExplained膨脹工況的解釋Tosummarize:概括如下Wetakethedifferencebetweentwoloadcasestodetermineadisplacementrange.兩個(gè)工況確定位移范圍Fromthisrangewecomputeaforcerangeandthenastressrange.由此我們確定力的范圍和應(yīng)力范圍Thecoderequirestheextremedisplacementstressrange.規(guī)范要求極端的應(yīng)力范圍Theuseronlyhastoworryaboutwhetherornotthe“extreme”casehasbeenaddressed.用戶僅考慮最大應(yīng)力范圍即可2023/1/9BasicStressTheory&LinearvsNon-Linear線性和非線性Terminologyappliestoboundaryconditions.邊界條件的類(lèi)型Recalltheequationbeingsolved:[K]{x}={f}Thisistheequationofaspring.Thepipingsystemboundaryconditions(i.e.therestraints)arerepresentedasstiffnesses,orsprings.管道邊界條件代表剛度或彈簧Morecomplexboundaryconditionscanbedefined,invalidatingthe“l(fā)inearspring”assumption.2023/1/9BasicStressTheory&LinearvsNon-Linear線性和非線性線性約束

boundaryconditionisadoubleactingrestraint,suchasa“Y”support.一種是上下約束Anotherexampleofalinearboundaryconditionisaspringhanger.一種是彈簧Theforceversusdisplacementcurvefortheserestraintsisastraightline…力和位移是線性關(guān)系Thereforetheserestraintsarelinear.約束是線性的Theslopeofthelineisthestiffness.斜率是剛度2023/1/9BasicStressTheory&LinearvsNon-Linear線性和非線性非線性約束A“+Y”supportisanon-linearsupport.支架Itsforcevsdisplacementcurveisnotastraightline.力和位移不是直線關(guān)系Stiffnessonlyexistsfornegativedisplacements.向下的位移是剛度是存在的Forpositivedisplacements,thestiffnessiszero.向上的位移，剛度變?yōu)椋?023/1/9BasicStressTheory&LinearvsNon-Linear線性和非線性A“gap”isalsoanon-linearsupport.間隙的引進(jìn)Theforcevsdisplacementcurveisnotastraightline.力和位移不是線性關(guān)系Thereisnostiffnessinthegap.間隙部分沒(méi)有剛度2023/1/9BasicStressTheory&LinearvsNon-Linear線性和非線性Frictionmakesarestraintnon-linear摩擦讓約束非線性Largerotationrodsarealsonon-linearrestraints大的轉(zhuǎn)動(dòng)吊桿讓約束非線性Non-linearrestraintsinajobmeanthat[Kope]isnotequalto[Ksus].非線性后，熱態(tài)管道剛度和冷態(tài)剛度不一致(EXP)and(OCC)loadcasesmustbeconstructedusingthedifferencebetweentwootherloadcasestoaccountfornon-linearrestraints.2023/1/9BasicStressTheory&偶然工況的建立Occasionalloadsareconsidered“primary”,sincetheyareforcedriven.偶然荷載是主要載荷，力引起的。Occasionalloadsoccurinfrequently.不經(jīng)常發(fā)生Thecodesemployan“allowableincrease”factorbasedonthefrequencyofoccurrenceinthedeterminationoftheallowable,i.e.k*Sh.基于發(fā)生的頻率，確定ｋ值的大小Examplesofoccasionalloadsarewindandearthquake.偶然載荷是風(fēng)載荷和地震載荷2023/1/9BasicStressTheory&偶然工況的建立ThecodeequationfortheOCCasionalloadcaseis:

MA/Z+MB/Z<kShHere,MAisthemomenttermfromtheSUStainedloads,冷態(tài)荷載引發(fā)力矩andMBisthemomentfromtheOCCasionalloads.偶然荷載引發(fā)力矩ThisequationstatesthattheOCCasionalcaseisthesumoftheSUStainedstressesandtheOCCasionalstresses.偶然工況是冷態(tài)和偶然的疊加Sowecan’trunaloadcasewithjusta“WIND”loadandsatisfythiscoderequirement.Whatabout“W+P1+WIND”asaloadcase?2023/1/9BasicStressTheory&OccasionalLoadCaseSetupThe“W+P1+WIND”casewillworkfor“l(fā)inear”systemsonly.For“non-linear”systems,thisisnotsufficient,forthesamereason“T1”isnotsufficientfortheEXPansionloadcase.ThebestwaytosetupOCCasionalloadcasesis:(1)W+P1+T1(OPE)(2)W+P1+T1+WIND(OPE)(3)W+P1(SUS)(4)DS1-DS3(EXP)(5)DS2-DS1(OPE)(6)ST5+ST3(OCC)2023/1/9BasicStressTheory&OccasionalLoadCaseSetup(1)W+P1+T1(OPE)(2)W+P1+T1+WIND(OPE)(3)W+P1(SUS)(4)DS1-DS3(EXP)(5)DS2-DS1(OPE)(6)ST5+ST3(OCC)ThisisthenormalOPEratingcaseThisisacombinedOPEratingcasewhichincludestheOCCloadsThisisthestandardSUStainedcaseThisisthestandardEXPansioncaseThisdifferenceyieldstheeffectsoftheOCCasionalloadonthesystem.Thisisnotacodecase,onlyaconstructioncase,therefore(OPE).Thishandlesnon-linearities.ThisisourOCCasionalcodecompliancecase,stressesfromPrimaryplusOccasionalloads.2023/1/9BasicStressTheory&工況的定義和維護(hù)CAESARIIwillrecommendloadcasesfor“new”jobs.By“new”jobs,wemeanjobsthatdonothavea“._J”file.For“old”jobs,havinga“._J”file,CAESARIIreadsinthedefinedloadcasesandpresentsthemtotheuser.Theloadcaseeditingscreenisshownattheright.2023/1/9BasicStressTheory&工況的定義和維護(hù)Onthisdialog,availableloadtypesarelistedintheupperleftlistbox.載荷類(lèi)型Availableloadcasetypesarelistedinthelowerleftlistbox.工況類(lèi)型Loadcases(recommendedorpreviouslydefined)areshowninthegridattheright.推薦生成的工況Recommendedloadcasescanalwaysbeobtainedbyclickingonthe[Recommend]button.Theanalysiscommencesbyclickingon“therunningman”.2023/1/9BasicStressTheory&LoadCaseGeneration&MaintenanceSayfora“new”job,theloadcasesattherightarerecommended.Sayyouacceptandruntheseloadcases.Uponreviewingtheoutputyoudiscoverthatpre-defineddisplacementsatnode5wereomitted.Youreturntoinput,addthedisplacements,andstarttheStaticAnalysisprocessoragain.2023/1/9BasicStressTheory&LoadCaseGeneration&MaintenanceCAESARIIreadstheseexistingloadcasesandpresentsthem.Whatwillyourresultsbeifyouruntheseloadcases?Exactlythesameasbefore,becausetheseloadcasesdon’tincludethepredefineddisplacements.Youmustmanuallyadd“D1”totheOPEloadcase,oraskCAESARIItore-recommendtheloadcases.2023/1/9BasicStressTheory&LoadCaseGeneration&MaintenanceNoticetheloadtypelistintheupperleftcontains“D1”now.Thecorrectedloadcasesareshownattheright.2023/1/9BasicStressTheory&LoadCaseGeneration&MaintenanceNoticetheloadtypelistintheupperleftcontains“D1”now.Thecorrectedloadcasesareshownattheright.2023/1/9BasicStressTheory&LoadCaseGeneration&MaintenanceNoticetheloadtypelistintheupperleftcontains“D1”now.Thecorrectedloadcasesareshownattheright.Anytimeyouaddorremoveacompleteloadtype,theloadcasesareinsufficient.Ifyouaddeddisplacementstonode110,wouldtheloadcasesbesufficient?2023/1/9BasicStressTheory&確保您分析對(duì)象的正確性RememberCAESARIIisafiniteelementprogram.有限元RememberCAESARIIusesa3Dbeamelement.3D梁?jiǎn)卧猂ememberyoumusthaveequilibrium:保持平衡Resultantloadsshouldequalappliedloads作用力等于反作用力Gravity(weightonly)loadcaseshouldequaltheweightofthesystem重力等于整個(gè)系統(tǒng)的總重量OtherbasicchecksVerifynodal3Dcoordinates尺寸輸入是否正確Checkforextremedisplacementsand/orloads最大位移和推力(seehandout)2023/1/9BasicStressTheory&ProblemSolving問(wèn)題的處理Whatdoyoudowhenyoudon’tliketheresults?Recalltheequationbeingsolved:

[K]{x}={f} wherewesolvefor{x},thedisplacementsFromthesedisplacements,wecomputeelementforces&momentsFromtheseforces&moments,theCodeequationsareappliedandwecomputestresses.2023/1/9BasicStressTheory&ProblemSolvingWhatdoyoudowhenyoudon’tliketheresults?Soifyouhaveastressproblem,itcanonlybecausedbytwothings:ACoderelatedissue(SIFs,codeequation,etc.)Extremeforcesand/ormomentsIfyouhaveaforce/momentproblem,theycanbecausedbyonlytwothings:ImproperelementcharacteristicsExtremedisplacements2023/1/9BasicStressTheory&ProblemSolvingWhatdoyoudowhenyoudon’tliketheresults?Ifyouhaveadisplacementproblem,itcanonlybecausedbytwothings:Improperinput(density,elasticmodulus,appliedloads)ImproperboundaryconditionsDon’tforgettocheckandrechecktheinput.Rememberthatin3Dsystems,aloadinonelocationcancausepivotingsomewhereelsedownstream,resultinginexcessiveforcesandmoments.Trytoisolatetheloadcausingtheproblem,andtraceitsorigin.2023/1/9BasicStressTheory&ProblemSolving設(shè)計(jì)和分析過(guò)程DesignbyAnalysis-TheDesignCycle收集數(shù)據(jù)Gatherallthedata,withassumptions建立分析模型和工況Generatethemodelandloadsets分析計(jì)算Performtheanalysis檢查結(jié)果Checktheresultsandassumptions診斷問(wèn)題Diagnoseanyproblems調(diào)整、改進(jìn)和精細(xì)模型Make