周期結構材料力學和電磁動態(tài)特性研究.pdf

1、碩士學位論文周期結構材料力學和電磁動態(tài)特性研究StudyonMechanicalandElectromagneticDynamicCharaeteristicsofMateri／alswithPeriodicStructures(國家自然科學基金資助項目項目批準號：50475150)作者姓名：學科、專業(yè)：學號：指導教師：完成日期：王塑注擔撼電王王捏20404105王睦明塑握2006—12大連理工大學DalianUniversityofT

2、echnolo毋r型塑墮塑塑型塑堂翌皇堡墊查塹堡塑墨StudyonMechanicalandElectromageficDynamicCharacteristicsofMaterialswithPeriodicStructuresAbstractMaterialwithperiodicstructuresisakindofstructuralbodyformedbymorethantwo虹ndsofmaterialswithdiffer

3、entparameterswhichalternateperiodicallyinspace，Asanoveltypeengineeringmaterial，itisbecomingamatterofconcemformoreandmorepeopleSomeparametersofmaterialwithperiodicstructuresalternateperiodicallyinthescaleofelectromagnetic

4、waveorelasticwaveDuetotheactionoftheperiodicstmctures，thematerialhasbandgapsStudyonbandgapsplaysaveryimportantroleinmaterialwithperiodicstructuresIthasabundantphysicalmeaningandbroadprospectofapplicationThefinite—differe

5、ncetime—domainmethod(FDTD)iSoneofthemostpowerfulnumericalmethodsforthemodelingoftheelectromagneticwave，elasticwaveandacousticwavepropagationandscatteringItisbasedonthediscretizationofpartial—differentialwaveequationsThep

6、artial—differentialequationsaretransformedtofinitedifferenceequationsbythediscretizationinthetimeandthespaceConsequently，therelationoffieldcomponentsandtimeinthediscretpointsisobtainedintheprocessofwavepropagationInthepa

7、perthetheoryofFDTDmethodinelectromagneticandelasticfieldiSstudiedandtwo—dimensionalandthree—dimensionaldifferencecellsandequationsareestablishedNumericalstabilityofthemethodalsodiscussedWhencomputingthefieldwiththeFDTDme

8、thod，thedeterminationofabsorbingboundaryconditionisallimportantaspectFirstly，thispaperdeducestheimpedancematchedconditionofperfectlymatchedlayerinelectromagneticfieldSecondly，PMLmodelforevolutionprobleminelasticfieldiSdi

9、SCUSSedfromtheviewpointofelastodynamicAveryhighdampingparameterandasmalllayerwidthareobtainedItcailcontrolthetransmissioncoefficientinaverysmallrangewhileachievingaquasiperfectabsorptionoftheincidentwaveFinallysquarestru

10、cturemodeloftwo—dimensionalperiodicmaterialiSdevelopedBasedonthedifferenceequations，programsaredevelopedtocalculatethetransmissioncoefficientinFXandFMdirectionofelectromagneticandelasticperiodicstructures，andthegapspectr

11、aareobtainedAdditionallybandgapsofperiodicstructures謝thnegativePoisson’sratioandlineardefectstructuresareanalyzedOneofcharacteristicsforFDTDmethodiSconvenientforvisualizationWavepropagationwassimulatedinperiodicand1inear