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ID:52439201
大小:1.05 MB
页数:38页
时间:2020-04-06
《骨科及康复生物力学.ppt》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、骨科及復健生物力學1骨小樑結構2Wolff’slaw˙Formfollowsfunction˙Bonehastheabilitytoadapt,bychangingitssize,shape,andstructuretothemechanicaldemandsplacedonit˙Boneislaiddownwhereneededandresorbedwherenotneeded˙Theremodellingmaybeeitherexternal(achangeintheexternalshapeofthebone)or(a
2、changeintheporosity,mineralcontent,anddensityofbone)3StructuralAdaptation4生物力學巨觀→微觀形態(Morphology)功能(Function)巨觀力學→微觀力學5有限元素法σ=CεF=KxK:stiffnessmatrixViscoelasticmodelσ=μdε/dtμ:viscositycoefficient6緻密骨(CorticalBone)組成:osteon,collagen,calcifiedtissue成骨細胞(osteoblaset)
3、蝕骨細胞(osteoclast)骨母細胞(osteocyte)細胞力學(CellMechanics)7海綿骨(CancellousBone)材料(material)及結構觀點(structure)材料性質:E結構性質:KTrussBarBeam8材料性質各向同性(Isotropic)OnlyoneE(K…)σ=Eετ=GγShearmodulusG=E/2(1+ν)AnisotropicStiffnessmatrixSizeeffectofMechanicalproperties9力學力(Force)變形(Deformati
4、on)PrincipalstrainStrainenergy應力(Stress)Principalstress10骨折癒合(FractureHealing)11骨折癒合(FractureHealing)12BiologyofFractureHealingThefracture(~7daysafterinjury)Thegranulationtissuestage(~twoweeks)Thecallus(4~16weeks)Theremodelingprocess(1~4years)Themodelingstage(oneor
5、moreyears)Theregionalacceleratoryphenomenon(RAP)13BoneRemodelingTheA–R–FsequenceA:ActivationR:ResorptionF:Formation14BoneModelingA-ForA-R15MechanicalAdaptationRemodeling:A-R-FModeling:A-ForA-R16骨折癒合(FractureHealing)17ConceptofInterfragmentaryStrain(ε)Perren&Cordey˙
6、Thetypeoftissueatthefracturegapcorrespondswiththedegreeofstrain˙Fracturehealingisaccompaniedbyasuccessivedecreasesofinterfragmentmotion˙Moresuitableforgaporcontacthealingmechanism18骨折癒合(FractureHealing)ε:Interfragmentarystrain19骨折癒合(FractureHealing)20骨折癒合Thehydrost
7、aticpressureisrepresentedas:Theoctahedralshearstressisgivenas:21骨折癒合22OsteogenicIndexwhereIisthescalarvalueoftheindex,iisagivenloadcase,cisthetotalnumberofdifferentloadcases,niisthenumberofloadingcyclesforagivenloadcase,Siisthecyclicoctahedralshearstress(alwaysposi
8、tive),Diisthecyclichydrostaticstress(negativeifcompression,positiveiftension),andkisanempiricalfactorweighingtherelativecontributionsofhydrostati
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