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壁板结构在热声环境下的动态响应计算与分析学院动力与能源工程学院专业飞行器动力工程班级7404101学号200704041035姓名赵宇指导教师沙云东负责教师沙云东沈阳航空航天大学2011年6月沈阳航空航天大学毕业设计（论文）I摘要针对薄壁结构在热声载荷作用下的动态响应问题，本文利用理论分析及数值模拟相结合的方法研究了薄壁结构在热声载荷作用下的非线性动态响应。首先建立了热声载荷作用下薄板振动的非线性大挠度方程，基于该方程建立Miles单自由度杜芬型模态方程，讨论非线性恢复力项对结构自由振动的影响，计算屈曲温度、热屈曲幅值，并分析了热屈曲前后刚度变化及应力应变响应统计特性。建立薄壁结构有限元模型，考虑几何非线性，结合有限元软件，对高温结构施加模拟的声载荷进行动响应计算，根据屈曲前后薄壁中点应力及横向位移概率分布，分析热及噪声载荷造成的结构几何非线性对结构刚度的影响。最后计算了三种典型壁板结构，平板，开孔板，加肋板在热噪声载荷作用下的动态响应，预测到了三种类型的跳变运动，计算了均方应力、均方应变、应力及应变功率谱密度。分析了温度和噪声对薄板刚度及热应力和应变分布的影响，不同结构对相应的影响。本文所研究的航空薄壁结构在热声载荷作用下非线性动态响应的计算和分析方法，以及所计算的结构应力/应变，对认识高速飞行器表面结构非线性动态响应及进行抗疲劳设计有着重要的参考价值。关键词：壁板结构；热声疲劳；动态响应；热屈曲；跳变响应壁板结构在热声环境下的动态响应计算与分析IICALCULATIONANDANALYSISOFDYNAMICRESPONSEOFTHIN-WALLEDSTRUCTUREUNDERTHERMAL-ACOUSTICLOADINGSAbstractAimingatthedynamicresponsesofthin-walledstructuresundercomplexloadings,withtheoreticalanalysisandnumericalsimulationemployed,nonlinearresponseofthin-walledstructureunderthermo-acousticloadingisinvestigated.Thenonlinearlargedeflectiongoverningequationofmotionforthinplateunderthermo-acousticloadingisestablishedfirstly.Thesimplestcase,asingleDOFequationisthenobtained.Theinfluenceofthenonlineartermofrestoringforceonfreevibrationisdiscussed.Thecriticaltemperatureandstaticdeflectionofthermalbucklingarecalculated.Aflatplate,astiffenedplateandaplatewithacircularholeinitscenterwithclampededgeconditionareselected.FiniteelementmodelsarebuiltincommercialcodeANSYS.Withgeometricnonlinearityandpre-stresseffectconsidered,thedynamicresponseofplatesunderdifferenttemperaturesandsoundpressurelevelsarecomputed,assumingthattheacousticloadistruncatedGaussianwhitenoiseandthethermalloadisuniformlydistributed.Basedonthetimehistoriesofdisplacementandstress,thepowerspectraldensity,probabilitydensityfunctionandstatisticsareobtained.Themethodandresultspresentedhavecertainvaluetotheresearchofthenonlinearresponseofthin-walledstructureunderthermo-acousticloadingandanti-fatiguedesign.Keywords:thin-walledstructure;thermal-acousticfatigue;dynamicresponse;thermal-buckling;snap-throughresponse沈阳航空航天大学毕业设计（论文）III符号表a,b,h板的长度，宽度和高度m临界载荷E泊松比S屈曲系数线膨胀系数a与b的比值四边简支板临界屈曲温度四边固支板临界屈曲温度R横向载荷壁板结构在热声环境下的动态响应计算与分析IV目录1绪论...................................................................................................................................11.1薄壁结构在声载荷下动态响应的研究方法.............................................................11.1.1确定噪声载荷的方法..........................................................................................11.1.2薄壁结构在噪声激励下的动态响应..................................................................21.2热声疲劳问题研究现状.............................................................................................31.2.1把问题简化成相应的随机振动问题..................................................................31.2.2建立有限元模型有限元方程..............................................................................31.3壁板结构在热声载荷下的动态响应.........................................................................41.3.1热声载荷对动态响应的影响..............................................................................41.4本文完成的主要工作.................................................................................................52热声载荷作用下薄壁结构动态响应的分析...................................................................62.1热声载荷作用下壁板大挠度位移方程建立.............................................................62.1.1Von-Karman大挠度方程......................................................................................62.1.2边界条件及横向位移的确定..............................................................................72.1.3屈曲温度的判定..................................................................................................82.2单自由度模型模态方程的建立.................................................................................92.2.1运动模态方程的建立..........................................................................................92.2.2非线性模态方程的性质....................................................................................102.3热屈曲幅值...............................................................................................................112.4薄壁板屈曲前后刚度变化.......................................................................................122.5功率谱密度法...........................................................................................................123热声载荷作用下薄壁结构响应数值分析.....................................................................143.1建立模型...................................................................................................................143.2计算结构框图...........................................................................................................173.3计算结果提取项目...................................................................................................173.4分析方案...................................................................................................................173.5实施过程和结果.......................................................................................................183.6得到位移及应力的时间历程....................................................