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24 个结果
  • 简介:用机能上地分级的材料(FGM)做的圆柱的壳的热弄弯行为被学习。材料成分由组成陶器并且金属。越过壳厚度的材料性质被假定以混合物的体积部分规则根据简单幂定律分布被分级。基于Donnell壳理论,以排水量部件弄弯的无尺寸的部分微分方程的一个系统被导出。变量的分离的方法被用来转变管理方程到平常的微分方程(颂诗)。一个射击方法被用来在边界条件的二种类型下面寻找微分方程的数字答案。幂定律索引,无尺寸的几何参数,和批评弄弯温度上的温度比率的效果详细被讨论。

  • 标签: 机能上地分级的材料(FGM ) 热弄弯 圆柱的壳 射击方法 O343.6 35K55
  • 简介:Thecuttingpropertiesofthefunctionallygradientceramiccuttingtoolsrelatecloselytothegradientdistribution.Acuttingmodelofthefunctionallygradientceramictoolisfirstlydesignedinthepresentpaper.TheoptimumofgradientdistributionisobtainedbywayoftheFEManalyses.

  • 标签: 压力场 陶瓷材料 倾斜分布 FEM
  • 简介:这个工作检验包含平行表面的板击碎,轮流出现的长度使遭到了到热震动的机能上地分级的材料(FGM)的破裂行为。在长、短的裂缝的尖端的热压力紧张因素(TSIF)用一种单个不可分的方程技术被计算。引起快克开始的批评热吃惊螖Tc用一个压力紧张因素标准被计算。为一个Al2O3/Si3N4FGM盘子的TSIF和螖Tc的数字例子被举在TSIF和螖Tc上说明热性质阶段,裂缝间距和裂缝长度比率的效果。为给定的裂缝长度比率,在长、短的裂缝的尖端的TSIF能显著地被减少,螖Tc能被介绍适当材料阶段提高,这被发现。TSIF也在裂缝间距与减少戏剧性地减少。在短裂缝的尖端的TSIF可能为在某些裂缝几何学条件下面的长裂缝比那高。因此,短裂缝可以开始首先在装载的热吃惊下面成长而不是长裂缝。

  • 标签: 功能梯度材料 断裂行为 裂纹板 材料表面 平行 应力强度因子
  • 简介:Diamond-likecarboncoatingshavebeenusedassolidlubricatingcoatingsinvacuumtechnologyfortheirgoodphysicalandchemicalproperties.Inthispaper,thehybridtechniqueofunbalancedmagnetronsputteringandplasmaimmersionionimplantation(PIll)wasadoptedtofabricatediamond-likecarbon-basedfunctionallygradientfilm,N/TiN/Ti(N,C)/DLC,onthe304stainlesssteelsubstrate.ThefilmwascharacterizedbyusingRamanspectroscopyandglancingX-raydiffraction(GXRD),andthetopographyandsurfaceroughnessofthefilmwasobservedusingAFM.Themechanicalpropertiesofthefilmwereevaluatedbynano-indentation.Theresultsshowedthatthesurfaceroughnessofthefilmwasapproximately0.732nm.Thehardnessandelasticmodulus,fracturetoughnessandinterfacialfracturetoughnessofN/TiN/Ti(N,C)/DLCfunctionallygradientfilmwereabout19.84GPa,190.03GPa,3.75MPa.m1/2and5.68MPa@m1/2,respectively.ComparedwiththatofDLCmonolayerandC/TiC/DLCmultilayer,thisDLCgradientfilmhasbetterqualitiesasasolidlubricatingcoating.

  • 标签: 类金刚石 功能 梯度薄膜 氮化钛 AFM 拉曼散射光谱
  • 简介:在这份报纸,为包含一个裂缝的机能上地分级的脱衣的飞机弹性问题被考虑。这被假定shear模量相互是厚度坐标的线性功能,当Possion的比率保持不变时。由利用Fourier转变技术和转移矩阵方法,混合边界问题被归结为数字地被解决的单个不可分的方程的一个系统。压力紧张因素和紧张精力版本率上的几何参数和分级的参数的影响被调查。数字结果证明分级的参数,长带的厚度和裂缝尺寸在压力紧张因素和紧张精力版本率上有重要效果。

  • 标签: 裂纹分析 功能梯度 剪切模量 权力 应力强度因子 应变能密度
  • 简介:IntroductionCeramic/metalfunctionalygradientmaterial(FGM)hasgradientingredientdistribution,soitspropertiesoftheheattransferan...

  • 标签: functionally GRADIENT MATERIAL THERMAL STRESS CYLINDER
  • 简介:Themainobjectiveofthispaperistostudythesingularnatureofthecrack-tipstressandelectricdisplacementfieldinafunctionallygradientpiezoelectricmediumhavingmaterialcoefficientswithadiscontinuousderivative.Theproblemisconsideredforthesimplestpossibleloadingandgeometry,namely,theanti-planeshearstressandelectricdisplacementin-planeoftwobondedhalfspacesinwhichthecrackisparalleltotheinterface.Itisshownthatthesquare-rootsingularityofthecrack-tipstressfieldandelectricdisplacementfieldisunaffectedbythediscontinuityinthederivativeofthematerialcoefficients.Theprob-lemissolvedforthecaseofafinitecrackandextensiveresultsaregivenforthestressintensityfactors,elec-tricdisplacementintensityfactors,andtheenergyreleaserate.

  • 标签: functionally gradient MATERIAL PIEZOELECTRIC MATERIAL stress
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  • 简介:Fromtheprocessofsedimentationthemathematicalrelationshipsamongdepositionvolumeandpowderpropertiesaswellassedimentationparameterswerededuced.Basedontheformulaamathematicalmodelwassetupandsimulatedthroughthecomputer.AtlastthevalidityofmathematicalmodelwassupportedbytherepresentativeexperimentonTi-MosystemFGMpreparedbyco-sedimentation.

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  • 简介:州空间的方法被采用评估形式的参数机能上地分级,magneto-electro-elastic,和multilayered盘子。基于机能上地分级的材料的性质是指数的假设,作为州的变量拿结构的排水量和压力的结构的颤动的州的方程被导出。自然频率和形式的形状基于在这篇论文给的州的方程和边界条件的一般答案被计算。有弹性的排水量上的机能上地分级的指数的因素的影响,电,并且结构的磁场被与不同的叠假定一个三明治板模型讨论序列。

  • 标签: 功能等级材料 磁电弹性板 态空间 固体力学
  • 简介:Basedonthefundamentaldynamicequationsoffunctionallygradedmaterial(FGM)cylindricalshell,thispaperinvestigatesthesoundradiationofvibrationalFGMshellinwaterbymobilitymethod.ThismodeltakesintoaccounttheexteriorfluidloadingduetothesoundpressradiatedbytheFGMshell.TheFGMcylindricalshellwasexcitedbyaharmoniclineradialforceuniformlydistributingalongthegenerator.TheFGMshellequationsofmotion,theHelmholtzequationintheexteriorfluidmediumandth...

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  • 简介:Thispaperpresentsahybridgradedelementmodelforthetransientheatconductionprobleminfunctionallygradedmaterials(FGMs).First,aLaplacetransformapproachisusedtohandlethetimevariable.Then,afundamentalsolutioninLaplacespaceforFGMsisconstructed.Next,ahybridgradedelementisformulatedbasedontheobtainedfundamentalsolutionandaframefield.Asaresult,thegradedpropertiesofFGMsarenaturallyreflectedbyusingthefundamentalsolutiontointerpolatetheintra-elementfield.Further,Stefest'salgorithmisemployedtoconverttheresultsinLaplacespacebackintothetime-spacedomain.Finally,theperformanceoftheproposedmethodisassessedbyseveralbenchmarkexamples.Theresultsdemonstratewelltheefficiencyandaccuracyoftheproposedmethod.

  • 标签: 功能梯度材料 瞬态热传导 元模型 混合 Laplace空间 拉普拉斯变换
  • 简介:Therelationshipbetweenthecriticalbucklingloadsoffunctionallygradedmaterial(FGM)Levinsonbeams(LBs)andthoseofthecorrespondinghomogeneousEuler-Bernoullibeams(HEBBs)isinvestigated.Propertiesofthebeamareassumedtovarycontinuouslyinthedepthdirection.ThegoverningequationsoftheFGMbeamarederivedbasedontheLevinsonbeamtheory,inwhichaquadraticvariationofthetransverseshearstrainthroughthedepthisincluded.Byeliminatingtheaxialdisplacementaswellastherotationalangleinthegoverningequations,anordinarydifferentialequationintermsofthedeflectionoftheFGMLBsisderived,theformofwhichisthesameasthatofHEBBsexceptforthedefinitionoftheloadparameter.Bysolvingtheeigenvalueproblemofordinarydifferentialequationsunderdifferentboundaryconditionsclamped(C),simply-supported(S),roller(R)andfree(F)edgescombined,auniformanalyticalformulationofbucklingloadsofFGMLBswithS-S,C-C,C-F,C-RandS-RedgesispresentedforthoseofHEBBswiththesameboundaryconditions.FortheC-Sbeamtheabove-mentionedequationdoesnothold.Instead,atranscendentalequationisderivedtofindthecriticalbucklingloadfortheFGMLBwhichissimilartothatforHEBBwiththesameends.ThesignificanceofthisworkliesinthatthesolutionofthecriticalbucklingloadofaFGMLBcanbereducedtothatoftheHEBBandcalculationofthreeconstantswhosevaluesonlydependuponthethroughthe-depthgradientofthematerialpropertiesandthegeometryofthebeam.So,ahomogeneousandclassicalexpressionforthebucklingsolutionofFGMLBsisaccomplished.

  • 标签: 临界屈曲载荷 功能梯度材料 欧拉-伯努利梁 光束 常微分方程 解析表达式
  • 简介:Thebendingresponsesoffunctionallygraded(FG)nanobeamswithsimplysupportededgesareinvestigatedbasedonTimoshenkobeamtheoryinthisarticle.TheGurtin-MurdochsurfaceelasticitytheoryisadoptedtoanalyzetheinfluencesofsurfacestressonbendingresponseofFGnanobeam.ThematerialpropertiesareassumedtovaryalongthethicknessofFGnanobeaminpowerlaw.Thebendinggoverningequationsarederivedbyusingtheminimumtotalpotentialenergyprincipleandexplicitformulasarederivedforrotationangleanddeflectionofnanobeamswithsurfaceeffects.IllustrativeexamplesareimplementedtogivethebendingdeformationofFGnanobeam.Theinfluencesoftheaspectratio,gradientindex,andsurfacestressondimensionlessdeflectionarediscussedindetail.

  • 标签: TIMOSHENKO梁理论 功能梯度材料 弯曲响应 表面应力 纳米 模型
  • 简介:Acomprehensivetreatmentoffractureoffunctionallygradedmaterials(FGMs)isprovided.Itisassumedthatthematerialpropertiesdependonlyonthecoordinateperpendiculartothecracksurfacesandvarycontinuouslyalongthecrackfaces.Byusingalaminatedcompositeplatemodeltosimulatethema-terialnon-homogeneity,analgorithmforsolvingthesystembasedonLaplacetransformandFouriertransformtechniquesispresented.Unlikeearlierstudiesthatconsideredcertainassumedpropertydistributionsandasinglecrackproblem,thecurrentinvestigationstudiesmultiplecrackproblemintheFGMswitharbitrarilyvaryingmaterialproperties.Transientthermalstressesarepresented.

  • 标签: functionally GRADED materials FRACTURE mechanics TRANSIENT
  • 简介:Thetransientfracturebehaviorofafunctionallygradedlayeredstructuresubjectedtoanin-planeimpactloadisinvestigated.Thestudiedstructureiscomposedoftwohomogeneouslayersandafunctionallygradedinterlayerwithacrackperpendiculartotheboundaries.Theimpactloadisappliedonthefaceofthecrack.FouriertransformandLaplacetransformmethodsareusedtoformulatethepresentproblemintermsofasingularintegralequationinLaplacetransformdomain.Consideringvariationsofparameterssuchasthenonhomogeneityconstant,thethicknessratioandthecracklength,thedynamicstressintensityfactors(DSIFs)intimedomainarestudiedandsomemeaningfulconclusionsareobtained.

  • 标签: 瞬时破裂 等级分层结构 动态压强因素 平面碰撞
  • 简介:Thispaperpresentsanexactsolutionofthecracktipfieldinfunctionallygradientmaterialwithexponentialvariationofelasticconstants.ThedimensionlessPoisson'sratiosv0oftheengineeringmaterials(iron,glass...)arefarlessthanone;therefore,neglectingthem,onecansimplifythebasicequationandtheexactsolutioniseasytoobtain.Althoughtheexactsolutionforthecasev0≠0isalsoobtained,itisverycomplicatedandthemainresultisthesamewiththecasev0=0(itwillbedealtwithinAppendixⅦ).Ithasbeenfoundthattheexponentialtermexp(ax+by)intheconstitutiveequationsbecomesexp(ax/2+by/2-kr/2)intheexactsolution.

  • 标签: 弹性常数 指数变化 功能梯度材料 弹性力学 材料力学
  • 简介:Wavepropagationanalysisforafunctionallygradednanobeamwithrectangularcross-sectionrestingonvisco-Pasternak'sfoundationisstudiedinthispaper.Timoshenko'sbeammodelandnonlocalelasticitytheoryareemployedforformulationoftheproblem.TheequationsofmotionarederivedusingHamilton'sprincipalsbycalculatingkineticenergy,strainenergyandworkduetoviscoelasticfoundation.Theeffectsofvariousparameterssuchaswavenumber,non-homogeneousindex,nonlocalparameterandthreeparametersoffoundationareperformedonthephasevelocityofthenanobeam.Theobtainedresultsindicatethatsomeparameterssuchasnon-homogeneousindex,nonlocalparameterandwavenumberhavesignificanteffectontheresponseofthesystem.

  • 标签: 弹性波传播 功能梯度 基础 TIMOSHENKO 非局部弹性理论
  • 简介:充满液体的机能上地分级的圆柱的壳的免费颤动特征隐居到有弹性的基础被一个分析方法调查。部分轴、尖的尺寸的有弹性的基础被Pasternak模型代表。壳的运动被代表由一阶砍说明旋转惯性的变丑理论并且横向砍紧张。机能上地分级的圆柱的壳由不锈钢和硅氮化物组成。材料性质以成分的体积部分根据幂定律分布通过厚度连续地变化。管理方程用RayleighRitz方法和一条变化途径被获得。液体被古典潜在的流动理论描述。数字例子被举并且与存在可得到的结果到相比验证现在的方法。充满液体的机能上地分级的圆柱的壳的免费颤动隐居到的图形的摘要有弹性的基础被一个分析方法调查。部分轴、尖的尺寸的有弹性的基础被Pasternak模型代表。壳运动被代表由一阶砍变丑理论。管理方程用RayleighRitz方法被获得。液体被古典潜在的流动理论描述。数字例子被举并且与存在可得到的结果到相比验证现在的方法。

  • 标签: 弹性基础 功能梯度 自由振动 圆柱壳 一阶剪切变形理论 充液
  • 简介:Humanμ-opioidreceptor(HμOR)withatagofsixconsecutivehistidinesatitscarboxylterminushasbeenexpressedinrecombinantbaculovirusinfectedSf9insectcells.Themaximalbindingcapacityforthe[^3H]diprenorphineand[^3H]ohmefentanyl(Ohm)were9.1±0.7and6.52±0.23nmol/gprotein,respectively.The[^3H]diprenorphineor[^3H]OhmbindingtothereceptorexpressedinSf9cellswasstronglyinhibitedbyμ-selectiveagonists[D-Ala^2,N-methyl-Phe^4,glyol^5]enkephalin(DAGO),Ohm,andmorphine,butneitherbyδnorbyκselectiveagonist.Na^+(100mM)andGTP(50μM)couldreduceHμORagonistsetorphineandOhmaffinitybindingtotheoverexpressedHμOR.μ-selectiveagonistsDAGOandOhmeffectivelystimulated[^35S]GTPγSbinding(EC50=2.7nMand6.9nM)andinhibitedforskolin-stimulatedcAMPaccumulation(IC50=0.9nMand0.3nM).Theagonist-dependenteffectscouldbeblockedbyopioidantagonistnaloxoneorbypretreatmentofcellswithpertussistoxin(PTX).TheseresultsdemonstratedthatHμORoverexpressedinSf9insectcellsfunctionallycoupledtoendogenousCi/oproteins.

  • 标签: 人类μ-河片受体 Sf9昆虫细胞 过表达 百日咳毒素 内源 Gi/o蛋白