简介:lObjectiveTalar身体破裂是稀罕的并且有差的处理结果。学习是报导关上的talardomefractures.MethodsEight的长期的外科的治疗结果的这的目的关上了talar身体破裂,在我们的水平与小碎片cancellous螺丝钉或Herbert螺丝钉由开的减小和内部固定对待我损伤中心回顾地被分析。脚(antero以后、侧面、倾斜的看法)和脚关节的外科手术前、手术后的拍(antero以后,侧面并且榫眼看法)被获得。病人被跟随在上面放射学地并且机能上地(脚功能索引,FFI)在3以后,星期,6个星期,3个月,6个月然后annually.ResultsThere是五压碎破裂并且三砍破裂(二sagittal砍并且一个花冠砍),与5年的平均后续。没有早复杂并发症在这些病人被注意。迟了的复杂并发症在四个病人在talar身体的六个病人和osteonecrosis包括了subtalar/ankle关节的osteoarthrosis。在功能的评价以后,在5年以后的吝啬的FFI是104.63个点,更坏的结果在压碎损害和花冠被注意砍破裂。Sagittal砍破裂有对通过手术对待的talar身体破裂随后的复杂并发症是的好功能、放射学的outcome.ConclusionsLate不可避免尽管准确减小和僵硬固定被完成,因此,病人们应当关于不利结果被建议。尽管压碎和花冠砍,破裂有差的结果,sagittal损害在长期的评估上有好预后。
简介:Thefracturetoughnessofhardbiomaterials,suchasnacre,bovinehoofwallandbeetlecuticle,isassociatedwithfibrousorlamellarstructuresthatdeflectorstopgrowingcracks.Theirhardnessandreducedmodulusweremeasuredbyusingananoindenterinthispaper.Micro/nanoscalecracksweregeneratedbynanoindentationusingaBerkovichtip.Nanoindentationofnacreandbovinehoofwallresultedinpile-uparoundtheindent.Itwasfoundthatthefracturetoughness(KC)ofbovinehoofwallisthemaximum,thesecondisnacre,andtheelytracuticleofdungbeetleistheleastone.
简介:一个有力的数字模型的发展长有模仿具体材料的破裂行为是在地震工程的主导的研究区域之一。一个可靠模型应该能足够地代表裂缝的不连续的特征并且在复杂装载条件下面模仿各种各样的失败行为。在这篇论文,数字明确的表达,它合并一个复杂僵硬塑料的接口联合弄软的结合的组成的模型,接触,磨擦并且砍膨胀进XFEM,被建议描述具体材料的各种各样的裂缝行为。为精确地在断绝的双方上装配贡献到弱形式的一个有效数字集成计划被介绍。建议方法的有效性被模仿几著名试验性的测试估计了。数字方法罐头成功地捕获裂缝路径并且精确地预言具体结构的破裂行为,这被结束。混合模式破裂行为上的mode-II参数的影响进一步被调查更好决定这些参数。
简介:ThispaperstudiesRabinovitch'scompressionexperimentsongraniteandchalkandproposesanoscillatingdipolemodeltoanalyseandsimulatetheelectromagneticradiationphenomenoncausedbyfractureofrocks.Ourmodelassumesthattheelectromagneticradiationpulsesareinitiatedbyvibrationsofthechargedrockgrainsonthetipsofthecrack.Thevibrationsoftherockgrainsarestimulatedbythepulsesofthecracks.OursimulationsshowcomparableresultswithRabinovitch'scompressionexperiments.Fromthesimulationresults,itverifiesanassumptionthatthecrackwidthisinverselyproportionaltothecircularfrequencyelectromagneticradiation,whichispresentedbyRabinovitchetal.Thesimulationresultsalsoimplythat,byusingouroscillatingdipolemodeltogetherwithRabinovitch'stwoequationsaboutthecracklengthandcrackwidth,wecanquantitativelyanalyseandsimulatetheelectromagneticradiationphenomenon,whichisinducedfromthefractureoftherocks.
简介:模型我伪静电干扰铝泡沫的非线性的骨折被考虑显微镜的异质的效果分析。第一,连续统组成的模型被收养说明金属性的泡沫的塑料压缩的可能性。二参数的Weibull类型功能建模的收益紧张在组成的模型被采用。然后,一个修改连贯的地区模型被建立在起始的裂缝前与一个连贯的地区描绘铝泡沫的破裂行为。张力的拖拉对本地裂缝开始排水量关系被采用描述材料的弄软的特征。并且为衔接破裂过程地区被用于考虑铝的显微镜的异质的在内的应力的山峰的一个Weibull统计模型起泡沫。最后,压力紧张的曲线上的随机的参数的影响被给。数字例子被给说明在这篇论文介绍的数字模型,J积分上的Weibull参数和材料性质的效果被讨论。
简介:Usingultrasonicguidedwavestoassesslongbonefracturesandfracturehealinghasbecomeapromisingdiagnosticissue.Butthemultimodeoverlapoftheguidedwaveschallengesthequantitativeevaluationandclinicalapplication.Inthepreformedstudy,inordertosimplifythesignalinterpretation,thelow-frequencysinusoidialsignalswereusedtoonlyexciteS0andA0modesinfracturedlongbones.TheamplitudesofS0andA0modeswerenumericallyanalyzedwithvariationincrackwidthandfractureangle.Numericalsimulation,basedonthetwo-dimensionfinite-differencetime-domain(2D-FDTD)revealsthatbothS0andA0amplitudesdecreasewiththefracturewidening.However,theincreaseinfractureanglegraduallyenhancestheA0amplitude,whilewithrespecttotheS0mode,itsamplitudeshowsanon-monotonictrendtothevariationinfractureanglewithaturningpointaround45°.TheamplituderatiobetweenS0andA0canreflectthevariationsincrackwidthandfractureangles.ThesimulationillustratesthatultrasonicguidedS0andA0modesaresensitivetothedegreeofbothverticalandobliquefracturesinthelongcorticalbone.Thesefindingsmaybehelpfulforfracturesdiagnosisandhealingevaluationofthelongbone.
简介:Bymeansofreasonableassumptionandmathematicalderivation,atheoreticexpressionofflowrateforasinglefracturewithlinearlyvaryingwidthwasobtained.Themathematicalderivationwasbasedonthecubiclawandthenewtheoreticexpressionwasanextentionoftraditionalparallelplatemodel.Thisstudymayhelptoanalyzeseepageinfracturedrockmass.
简介:Hydrogenembrittlementisoneofthekeyissuesforthevanadiumalloysforfusionapplication.PreviousstudyhasshownthatV4TialloyhadbetterpropertiesagainsttheembrittlementthanV4Cr4TiandV4Ti3A1alloys.Itwasthoughtthatthebetterpropertywasbenefitedfromthesmallratioofitsyieldstrengthoveritsultimatetensilestrength.
简介:Researchonprobabilityofseismiccriticalinstabilityonbasisof''fracturecollusion''modelSHI-YONGZHOU1)(周仕勇),LING-RENZHU1)(朱令人),MA...
简介:Thisstudyconcernsatwo-dimensionalmodelandthecorrespondingvirtualcrackclosuretechnique(VCCT)implementedtosolvethegeneralboundaryvalueproblemsthatmayexplainwhyinterfacediscontinuityhaseffectsonthefracturebehaviorinthesuperconductor-substratesystem.Theinterfacialdiscontinuitycanbeclassifiedaccordingtothematerialproperties'continuityandtheirderivatives'continuityattheinterface.Fornonhomogeneoussuperconductorandsubstratespecimenswithvariousmaterialproperties,aVCCTmethodisdevelopedtocalculatetheirfracturebehavior.Furthermore,theeffectsofappliedmagneticfieldamplitudeandnonhomogeneousparametersareextensivelyandparametricallystudiedintwoactivationprocesses(zero-fieldcoolingandfieldcooling).Theintegrativeandcomputationalstudypresentedhereprovideafundamentalmechanisticunderstandingofthefracturemechanisminthesuperconductor-substratesystemandshedslightontherationaldesignofinterfacialcontinuity.
简介:Themultilayered7XXXseriesaluminumalloywasimpactedby7.62mmogivalprojectilesatvelocitiesrangingfrom787to851m·s~(-1).Thedeformedmicrostructureundervariousimpactingvelocitiesandfracturesurfacesofdifferentsectionswereinvestigatedatdifferentphysicalscalestodeterminetheprocessoffailure.Opticalmicroscopy(OM),electronback-scattereddiffraction(EBSD)andscanningelectronmicroscopy(SEM)wereusedintheinvestigation.Theresultsshowthatcraterisconstrainedinthe7B52frontlayerandtwotypesofadiabaticshearbandswhicharetransformedbandsanddeformedbandsanddifferenttypesofcracksareobserved.Spallfractureisthesignificantfailuremodeof7B52frontlayer,andtheresultingdelaminationleadstothepresenceofbendingtensilefractureinsteadoftheshearplugging.Theductile7A01layerbluntsanddeflectsthespallcracktips,preventingthetargetsfromfullspall,andinducesaconstraintof7A52rearlayer.Theleveloftheconstraintdeterminesdifferentfracturemodesof7A52layer,accountingfortheasymmetryofdamage.
简介:Objective:Toobservetheeffectofoctyl-a-cyanoacrylateuponbonehealinganditsdegradationinvitroaftermiddletibialtransversefractureinrabbits,andtoestablishtreatmentofhigherefficacywiththeapplicationofoctyl-a-cyanoacrylate.Methods:MiddletibialtransversefracturemodelofNewZealandrabbitswasestablished.Intheexperimentalgroup,internalfixationwith2mmKirschnerwireswasperformedandthebrokenendswerefixedwithoctyl-a-cyanoacrylate.Inthecontrolgroup,onlyinternalfixationwith2mmKirschnerwireswasconducted.Animalswerekilledatpresettimeintervalsof2,4,6,8,10and12weekspostoperativelyandsampleswereharvested.Results:Twoweeksafteroperation,clearfracturelineswereobservedinboththeexperimentalandthecontrolgroups.Fibroussofttissueconnectionwasnotedbetweenthebrokenendsandtherewassofttissueadhesionaroundthefracturesite.Therewasnocallusformationandthebrokenendsweresurroundedbyadhesivesofttissues.Obviousexternalcallusformationwasconfirmedat8weeksafteroperationinbothgroupswithpartialdisappearanceoffracturelines.Tenandtwelveweeksaftertheoperation,fracturelinesdisappearedcompletelyandtherewasobviousexternalcallusformationandboneunion.Inthefourthweek,fibrouscellsandchondrocyteswerefoundtogrowintothecolloidandsurrounditatthe6thweek.Theadhesivematerialwasdegradedandgraduallyabsorbedatthe8thweek.Chondrificationwasobserved.Conclusions:Twoweeksafterfixationfortibialfractureinrabbits,octyl-a-cyanoacrylatebeginsinvivodegradation.Chondrocytesandfibrocytesgraduallygrowintothedegradationareaandsurroundtheadhesivematerial,whichbrokeintopiecesat8weeks.Completedegradationanddisappearanceoftheadhesivematerialispresentbetween10and12weeks.Nobarriereffecthamperingfracturehealingisnoted.
简介:Themovementofwaterflowinunsaturatedfracturedrockwasinvestigatedwiththesandstonesamplethroughexperimentalresearchandnumericalsimulation.Theexperimentalresultsshowthatthearrivingtimeofwettingfrontisdelayedbythefracture,resultingintheincreaseofwatersaturationinthedomainontheupstreamsideofthefracture,whichwilllocallyenhancewaterflowthroughthematrix.Thenumericalsimulationwiththefinitevolumemethodcaptureseffectivelythesecharacteristics.Thecomparisonbetweensimulatedandobservedtraveltimeandarrivingtimeofwettingfrontshowsthattheirdifferenceareverysmallandthesimulatedresultsareinagreementwiththeobservedresults,whichimpliescalibratedparametersarereliableandeffective.Thenaccordingtothecalibratedparameters,fracturedmodelswereestablishedtoexaminehowthechangeoflargefracturedaperturewouldaffectthearrivingtimeofwettingfronts,pressureheadsandwatersaturationontheupstreamanddownstreamsidesoffracture.
简介:Crackopeningdisplacement(COD)wasappliedtocharacterizethefractureinitiationofthetoughhighdensitypolyethylene.Normalsinglesidenotchedthree-pointbendspecimensandsilicarubberreplicatechniqueswereusedtostudythecharacteristicCODofhigh-densitypolyethylenepipeanditsbutt-fusionjointsincludingtheweldfusionzoneandheataffectedzoneatdifferenttemperaturefrom-78℃to20℃.TestingresultsshowthatthecharacteristicCODappearstodependonthestructuralfeaturesthataredeterminedbyweldingprocessandthetestingtemperature.Asthetemperatureislowered,thecharacteristicCODofallzonesstudieddecreases.Becausetheweldingprocesssignificantlychangessomestructuralfeatureofthematerial,characteristicCODoftheweldfusionzoneisthesmallestoneamongthoseofthethreezones.TheresultscanbeusedfortheengineeringdesignandfailureanalysisofHDPEpipe.
简介:TheMayangCudeposit,westernHunanisamiddle-scalesandstone-typeCudepositpredominantofnativecopper.Fromanangleofgeologicalintegrativefield,fracturegeochemicalfeaturesarestudidedanddiscussedinthispaper.Infracturestructure,variantregularityandtheratiosofelementcouplesparticipatinginmetallogensisthattheirgeochemicalnaturesaresimilarorstronglycorrelative,revealchanginglawsofmetallogenictemperatureandpressurefieldsandmigratingdirectionofmetallogenicelements.Thetheoreticalstudytalliesmuchbetterwithproductivepractice.Theyaremeaningfultoconductprospectingandexployation.