铁磁材料非线性磁弹性耦合理论及其在超磁致伸缩智能材料中的应用

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1、兰州大学博士学位论文铁磁材料非线性磁弹性耦合理论及其在超磁致伸缩智能材料中的应用姓名：周浩淼申请学位级别：博士专业：力学、固体力学指导教师：周又和20070401蔺喇矢争博士学位论文摘要善的耦合理论框架。该理论框架对于铁磁材料在外磁场下的变形无论是定性分析还是定量计算都具有可行性，并且对新型功能材料一一超磁致伸缩材料的力磁耦合理论分析和数值计算也是十分重要的。通过本文的研究，初步显示了力学方法在铁磁材料非线性磁弹性耦合研究方面的广阔前景，为更加深入地研究铁磁材料力一电一磁一热多场耦合问题奠定了一定

2、的基础。关键词：局部耦合；全局耦合；非线出噬弹性耦合；广义变分原理；超磁致伸缩材料；非线性磁化；超磁致伸缩棒致动器；超磁致伸缩层致动器，磁致伸缩本构模型；非线性力一磁耦舍；饱和现象；应力敏感性；△E效应；倍频现象；共振和超谐共振；振动主动控制Ⅱ蔺孵幺亨博士学位论文A10酣actAbstractAlongwiththedevelopmentofmodemhi．ghandnewtechnologyrealm,ferromagneticmaterialsplaymoreandmoreimportantr

3、olesinmodemindustry．Forexample，therearemanyferromagneticmaterialsinelectricmachines(suchasgeneratorsandtransformer)whichareconvenientinelectricalenergyproductionandtransportation．However,therestillexistaseriesofcomplicatedunsolvedproblemsintheseequipm

4、ents．Oneofthemisgeneratorsandtransformer'svibrationandnoiseproblem．Theinvestigativeresultsbyengineersshowthatamainreasonaboutthevibrationandnoiseofelectricmachineisbecauseofthevibrationandnoiseofthesiliconsteelsheetsinitscores，sotheessentialproblemoft

5、hevibrationofelectricmachinesisthemechanicaldeformationofferromagneticmaterialsinducedbyelecn'omagneticfield．Duringoperation，sinasoidalalternatingmagneticfieldsestablishedinsidethecoreswouldcausemagneticforcesandthencal／sethevibrationsofsiliconsteelsh

6、eetsandmakenoise．Ifonlyconsideringtheeffectofmagneticforces．itishardtoexplainthefrequencymultiplicationphenomenonindynamicresponse．Thus，themagnetostrictivephenomenonofferromagneticmaterialsundermagneticfieldbecomesahotresearchtopic．Inconclusion,akeypr

7、oblemoftheresearchesofvibrationandnoiseinelectricmachinesispresentingadeformationmodelofferromagneticmaterialsbymagneticforcesandmagentostrietionundercomplexmagneticfields．Thepresentstudyaboutnonlinearmagneto-elasticcouplingofferromagneticmaterialsisb

8、asedonaboveconsiderationsinthispaper．Firstly,thispaperdealwiththelocalcouplingtheoryofferromagneticmaterials，namelythenonlinearmagneto-mechanicscouplingconstitutiverelations．Forbetterdescribingthecomplexbehaviorofferromagneticmaterials，anonlin