简介:TheflowthroughasinglefractureisnumericallystudiedbymeansoftheFluentSoftware.Theresultsshowthattheroughnessofthefracturesignificantlyaffectsthehydraulicconductivityinthefractureascomparedwiththecubiclawmodelwidelyusedtodescribetheflowbetweentwosmoothparallelplates.Anewmodelisproposedinthispaper,thenon-symmetricsinusoidalfracturemodel,tosimulatetheflowinarealfracture.Thismodelinvolvestwosinusoidal-varyingwallswithdifferentphasestoreplacetheflatplanesinthecubiclawmodel.Therelationshipsbetweentheeffectivehydraulicaperturesandthephaseretardationfordifferentrelativeamplitudesandwavelengthsarenumericallyinvestigated.Asimpleexpressionoftheeffectivehydraulicapertureofthefractureisobtained,togetherwiththelawoftheeffectivehydraulicapertureagainsttheamplitude,thephaseretardationandthewavelengthoftwosinusoidal-varyingwalls.
简介:无
简介:如果误诊,距骨的侧面的过程破裂是有一个潜力的稀罕损害引起重要病态。这些破裂的适当管理仍然是争论的,仅仅一些报告在这个题目上是可得到的。我们在在损害的时候被误诊的距骨的侧面的过程上与忽视的骨折介绍了37岁的男性的一个案例。长期的脚关节疼痛地在错误诊断以后介绍给7个月的病人。我们的案例在它是在湾穴tarsi作为松开的身体介绍了的距骨的侧面的过程上的忽视的骨折的一个稀罕案例的意义是唯一的。然而,有松开的身体的切除的一个手术与2years’一起介绍了令人满意的结果后续。到我们的知识,它应该是在英语文学报导的第一个案例。通过这份案例报告,当评估损伤到脚关节的侧面的方面时,我们为如此的稀罕多骨的损害强调怀疑的高索引的重要性并且讨论这些破裂的管理的原则。
简介:
简介:TDepartmentofOrthopaedics,TheRedCrossHospital,Shenzhen518029,China(CenJW,LiMC,NongSYandYanH)hefailureofusinggeneralintramedul...
简介:Objective:Tostudythechangeofthestressshieldingrateofstress-relaxationplateinvivoanditsinfluenceonfracturehealing.Methods:Thediaphysesofbilateraltibiasin70NewZealandrabbitswereosteotomizedandfixedwithstressrelaxationplates(SRP,theSRPgroup)andrigidplates(RP,theRPgroup),respectively.Thefracturehealingprocessinthese2groupswasinvestigatedbyradiography,lightandpolarizedlightmicroscopyandbiomechanicaltestat2to48weekspostoperatively.Results:Earlyafterfixationthestressshieldingratewasabout70%inbothgroups.WhileintheSRPgroupthestressshieldingratedecreasedgraduallyastimepassed,whyichwassignificantlylowerthanthatoftheRPgroup(P<0.05)bytheendofthe8thpostoperativeweek,andstabilizedatthelevelofabout27%at36-48weeksafterfixation.AbundantexternalcallusassociatedwiththeformationofcartilaginouscalluscouldbeobservedintheSRPgroupat2-4weekspostoperatively.Thetransformationofthecallusintothelamellarbonebeganat8-12weeks,thecollagengraduallyarrangedinorder,andthemechanicalnatureoftheunitedbonewasgraduallystrengthened,too.IntheRPgroup,theexternalcalluswasscarceattheearlystageoffracturehealing,andthecallusremodelingatthelatestageoffracturehealingwasdominatedbyboneabsorption.Theultimatebendingstrength(UBS)wasonly57.95%ofthatofthenormalby48weeks.Conclusions:ThedecreaseofthestressshieldingrateofSRPinvivowaswellinterrelatedwiththetimeoffixation.TheapplicationofSRPcouldpromotethecallusformationandbonereconstructionthustofavortherecoveryofthemechanicalstrengthoftheunitedbone.
简介:TherelationshipbetweenCharpyabsorbedenergyandthefracturetoughnessbymeansofthe(cracktipopeningdisplacement(CTOD))methodwasanalyzedbasedontheWeibullstresscriterion.TheCharpyabsorbedenergyandthefracturetoughnessweremeasuredfortheSN490Bsteelundertheductile-brittletransitiontemperatureregion.FortheinstrumentedCharpyimpacttest,thecurvesbetweentheloadingpointdisplacementandtheloadagainsttimewererecorded.ThecriticalWeibullstresswastakenasafracturecontrolledparameter,anditcouldnotbeaffectedbythespecimenconfigurationandtheloadingpatternbasedonthelocalapproach.TheparameterscontrolledbrittlefractureareobtainedfromtheCharpyabsorbedenergyresults,thenthefracturetoughnessforthecompacttension(CT)specimenispredicted.Itisfoundthattheresultspredictedareingoodagreementwiththeexperimental.ThefracturetoughnesscouldbeevaluatedbytheCharpyabsorbedenergy,becausethelocalapproachgivesagooddescriptionforthebrittlefractureeventhoughtheCharpyimpactspecimenortheCTspecimenisusedforthegivenmaterial.
简介:MagnesiumalloyEZ10(Mg-RE-Zn)wasdeformedintensionattemperaturesfrom20upto520°C.Arapiddecreaseoftheyieldandtensilestrengthwithtemperaturewasobservedattemperatureshigherthan300°C.Ontheotherhand,ductilityofsamplesrapidlyincreasedinthesametemperaturerange.Lightmicroscopyandscanningelectronmicroscopywasusedtorevealthereasonforthesebehaviours.Intermetallicparticlesingrainboundariesareresponsibleforexcellentmechanicalpropertiesatlowertemperatures.Diffusionalprocessesoccurringattemperatureshigherthan300°Csignificantlyinfluencedthedeformationmechanismaswellasthefracturecharacter.
简介:Threedifferenttypesoftensilestrength(TS)980MPagradeadvancedhigh-strengthsteelsusedinautomotiveapplications,namely,980MS(martensitesteel),980DP(dualphase)and980QP(quenchingandpartitioning)steelswereexamined.ThedelayedfractureresistanceofthesteelswasevaluatedusingaU-bendtest,slowstrainratetest(SSRT)andaconstantloadtensiletest.Theresultsindicatedthatallthesteelscouldpassthe300hHClsolutionimmersiontestandnoneoftheU-bendspecimenswasfracturedinthetest.However,thesteelsexhibiteddifferentsusceptibilitiestodelayedfractureunderSSRTandtheconstantloadtensiletests.980DPexhibitedthehighestresistancetodelayedfractureamongallthesamples,while980MSwasfoundtobethemostsusceptibletodelayedfracture.
简介:客观:为了调查汽车的效果,控制在试验性的骨折愈合和它的机制上锁钉子(AMLN)的微运动。方法:经历大腿骨的柄的横向的截骨术的双方的16只山羊分别地是有AMLN和Gross-Kempf(GK)钉子的固定intramedullary。后续时间是7,14,28和56天。Roentgenographic,简历机械,组织学,显微镜的扫描电镀物品和生物化学的分析是done.Results:(1)在在修理AMLN的组的fractural结束的反压缩,反屈曲和反扭转的力量比GK修理钉子的组的高;而,在折断的结束的压力躲蔽处的率显著地减少了(P<0.01)。(2)在修理AMLN的组的全部的骨胶原,不可溶解的骨胶原,钙和磷酸盐的内容在GK修理钉子的组比那高(P<0.05)。(3)胼胝的组织学的观察和定量分析表明AMLN能支持桥胼胝和骨膜胼胝的生长。因此愈合的制造和早完成的remolding过程,它比传统的GK好一些钉固定。(P<0.05)。(4)7-14天张贴操作,AMLN-fixedgroup的胼胝繁荣并且camellarly安排了,骨胶原纤丝在骨头trabecula的吸收空隙常常形成了。28-56天柱子操作,骨胶原纤丝是在吸收空隙附近繁荣并且与骨头平行“s纵的轴。活跃多骨的吸收和形成被看见,那么是remolding并且重建。Haversian系统是未经触动的,因为钙盐的免职,多骨的结构的网是很强的。任何一个都没在GK修理钉子的组上述调查结果被观察。结论:AMLN的设计与塑料固定理论一致很好。因为无变态的系统由theintramedullary固定仪器和破裂的近似、远侧的结束组成了的几何学是很坚挺的ands,搁置,到在fractural结束散布的物理压力的骚乱是轻的。在fractural部分之间的断断续续的物理压力的Thegeneration和行为能到达在压力行为和压力保护之间的平衡。特征愈合和remolding同时发生加快愈合的fractural过程。
简介:Objective:Toevaluatetheclinicalresultsoftreatmentofmidshafttibialfracturewithexpandableintramedullarynailscomparedwithinterlockingintramedullarynails.Methods:FromJune2003toAugust2005,46patients(27malesand19females,aged20-74years,mean=38.4years)withmidshafttibialfractureweretreatedsurgicallyinourdepartment.Thecausesoffracturesweretrafficinjuryin21patients,fallinjuryin6,tumblinginjuryin11andcrushinginjuryin8.AccordingtoAO/ASIFclassification,TypeAfracturewasfoundin16patients,TypeBin11,TypeC_1in5,andTypeC_2in2.Openfractureswerefoundin12patients,accordingtoGustiloclassification,TypeⅠin9patientsandTypeⅡin3patients.Basedonthepatients'consent,24patientsweretreatedwithexpandableintramedullarynails(GroupA)and22withinterlockingintramedullarynails(GroupB).Theoperationtime,bloodlossduringoperation,X-rayfluoroscopictimes,hospitalizationtime,weightbearingtimeafteroperation,healingtimeoffractureandcomplicationsofallthepatientswererecorded.TheclinicaleffectsofallthecaseswereevaluatedaccordingtothecriteriaofJohner-Wruhs.Results:Allthepatientswerefollowedupfor12-34months(mean=16.2months).Thetimeofoperation,thebloodloss,X-rayfluoroscopictimes,hospitalizationtimeandhealingtimeoffractureofGroupAsignificantlydecreased(P<0.05)comparedwiththoseofGroupB,butthetimeforweightbearingafteroperation,theJohner-WruhsdegreeofclinicaleffectsandcomplicationshadnosignificantdifferencebetweenGroupAandGroupB(P>0.05).Conclusions:Expandableintrameduilarynailcanshortenoperationtime,decreasebloodlossandreduceinvasion,whichisasafeandeffectivetreatmentmethodfortibialmidshaftfracture.
简介:Aclosed-formsolutionforpredictingthetangentialstressofaninclusionlocatedinmixedmodeⅠandⅡcracktipfieldwasdevelopedbasedontheEshelbyequivalentinclusiontheory.Thenamixedmodefracturecriterion,includingthefracturedirectionandthecriticalload,wasestablishedbasedonthemaximumtangentialstressintheinclusionforbrittleinclusioninducedfracturematerials.Theproposedfracturecriterionisafunctionoftheinclusionfracturestress,itssizeandvolumefraction,aswellastheelasticconstantsoftheinclusionandthematrixmaterial.Thepresentcriterionwillreducetotheconventionaloneastheinclusionhavingthesameelasticbehaviorasthematrixmaterial.Theproposedsolutionsareingoodagreementwithdetailedfiniteelementanalysisandmeasurement.
简介:Inpatientswhohavesustainedtraumaticbraininjurywithassociatedextremityfracture,thereisoftenaclinicalperceptionthattherateofnewboneformationaroundthefracturesiteincreases.Anovergrowthofcallusisobservedandectopicossificationevenoccursinthemuscle,butthemechanismremainsunclear.Whetherthisrapidly-formednewboneisfracturecallusoravariantofheterotopicossification,acommoncomplicationoftraumaticbrain
简介:Mechanicalpropertiesofgalvannealed(GA)steelsheetusedforautomotiveexposedpanelandpredictedfailurephenomenonofitscoatinglayerwereevaluatedusingfiniteelementmethod.V-bendingtestwasperformedtounderstandbetterthefractureofcoatinglayerofGAsteelsheetduringplasticdeformation.Yieldstrengthofthecoatinglayerwascalculatedbyusingarelativedifferencebetweenhardnessofcoatinglayermeasuredfromthenano-indentationtestandthatofsubstrate.Tomeasureshearingstrengthattheinterfacebetweensubstrateandcoatinglayer,shearingtestwithtwospecimensattachedbyanadhesivewascarriedout.Usingthemechanicalpropertiesmeasured,aseriesoffiniteelementanalysescoupledwithafailuremodelwasperformed.Resultsrevealthatthefractureofcoatinglayeroccursinanirregularmannerattheregionwherecompressivedeformationisdominant.Meanwhile,aseriesofverticalcracksperpendiculartomaterialsurfaceareobservedatthetensilestressed-region.Itisfoundthat0.26-0.28oflocalequivalentplasticstrainexistsatthecoatingandsubstrateatthebeginningoffailure.Thefractureofcoatinglayerdependsonductilityofthecoatinglayerconsiderablyaswell.
简介:Tosutdythemechanicalpropertiesandtheclinicalresultsofminimum-contactplateinthetreatmentoffractures.Methods:Four-pointbendingandtorsiontestswereconductedtocomparethenewminimumcontactplate(MCP)withdynamiccompressionplate(DCP)andlimitedcontactdynamiccompressionplate(LC-DCP).Thefracturehealingtimeandgrowthofhonycalluswereobservedin29casesoflongbonefracturefixedwithMCPtoevaluatetheadvantagesofthiskindofplate.Results:The29patientswhounderwentMCPwerefollowedupfrom6to14months.Theaveragehealingtimeforfemoral,tibialandhumeralfractureswas12,13and10weeks,respectively.Allfractureswerehealed.Nodisplacementoffracture,screwpullout,deformationorhreakoftheplatewerefound.Conclusions:ThebendingstiffnessofMCPissignificantlygreaterthanthatofDCPandLC-DCP(P<0.05).MCPcanprotecttheperiostealhloodsupplyagainstavascularosseousnecrosisandacceleratehonehealing.Itisakindofreliableandeffectiveplateintreatmentoffractures.