车架结构动力学仿真

1、课程名称结构动力学仿真实验名称车架结构的动力学仿真分析姓名学号导师实验组别同实验者评定成绩审阅教师实验报告要目实验目的实验要求实验软硬件实验方法步骤实验结果实验讨论、实验目的1.掌握几何建模基本方法2.掌握模态分析、频响分析和瞬态分析的一般性流程3.掌握如何用分析结果的图形化显示方法，并进行结果分析二、实验要求如图所示中空对称结构（以G、A中点和L、F中点连线为对称轴），L和F端固定在刚性墙上。采用壳单元建模，通过有限元分析，计算该结构的动力学特征和在特定激励下的动响应。Units;mmW仁加3W2=1,182L1=1,518L2=865Sizeofrectangularhollowbeam:

2、53x111to53x191dependingonlocations.Thicknessofshell;3.5L3=927L4=3611）计算该结构的前10阶固有模态。2）假设模态阻尼比为0.003，在A端外廓处作用垂直于纸面的单位正弦激励，计算A、G端外廓处的加速度响应频响函数和位移频响函数。（3）若A端外廓处作用的载荷为三角形冲击载荷，载荷幅值为100N，三角形冲击载荷的脉冲宽度为3ms，计算计算A、G端外廓处的加速度响响应和位移响应。（材料杨氏模量为210GPa,泊松比为0.3，密度为7890kg/m3。）三、实验软硬件计算机型号：华硕A45V；配置：显卡类型：入门级独立显卡;显存容量：

3、2GB；CPU主频：2.3GHz核心数：四核心/八线程软件名称：patran2010和Nastran2010四、实验方法步骤1.模态分析新建名为mode.db的模型文件，并选择MSC.Nastran进行结构分析File/NewFilename=chejia.db/OK/AnalysisCode=MSC.Nastran/AnalysisType=Structural/OK调整patran单位制Preference/Geometrygeometryscalefactor=1000.0(Milimeters)从外部文件导入名为chejia.igs的几何模型(CATIA作图)File/ImportOb

4、ject=Model/Source=IGES/文件名=chejia.igs/Apply/Ok划分单元网格，网格类型为4节点四边形单元(Quad4),全局单元边长取10Elements/Action=Create/Object=Mesh/Type=Surface/ElemShape=Quad/Mesher=Paver/Topolgy=Quad4/SurfaceList=Surface1:24/GlobalEdgeLength=10/Apply网格去重Action=Equivalence/Object=All/Method=ToleranceCube/EquivalencingTolerence=

5、0.005/Apply创建材料属性。弹性模量210Gp，泊松比0.3，密度7890kg/m3Materials/Action=Create/Object=Isotropic/Method=ManualInput/MaterialName=steel/InputProp.ElasticModulus=210e6/PoissonRatio=0.3/Density=7890e-9/OK/Apply(注意：本文件单位制采用mm,因此此处弹性模量和密度需要作出相应的单位转换)创建单元属性。壳单元厚度为3.5mmProperties/Action=Create/Object=2D/Type=Shell/P

6、ropertySetName=shell/InputProp.MaterialName=steel/Thickness=3.5/OK/SelectAppli.ApplicationRegion=Surface1:24/Add/OK/Apply备份.db文件，方便后续频响分析以及瞬态分析File/Saveacopy./文件名=frequency.db；File/Saveacopy./文件名=time.db；定义约束条件。车架L,F端固定Loads/BCs/Action=Create/Object=Displacement/Type=Nodal/NewSetName=fix/inputDataTr

7、anslations=/Rotations=/OK/SelectAppli.Select=Geometry/ApplicationRegion=Surface1、5/Add/OK/Apply定义分析类型并进行分析Analysis/Action=Analyze/Object=EntireModel/Method=FullRun/SolutionTypeSolutionType=NORMALMODES/OK/Subcases/SubcaseName=Default/SubcasePara.NumberofDe.=10/OK/Apply/Apply读取计算结果并观察各阶振型Action=Access

8、Results/Object=AttachXDB/Method=ResultEntities/selectresultsfiles=chejia.xdb/ApplyResults/Action=Create/Object=QuickPlot/SelectRe.=Default,A1:Mode:./SelectFri.=Eigenvectors,./Quantity=Magnitude/SelectDe.=Eigenvectors,./Apply2.频响分析打开备份文件frequency.db进行频响分析File/open/文件名=frequency.db创建载荷工况Load/BCs/Creat

9、eLoadCases/Action=Create/LoadCaseName=case1/MarkCurrent(选中)/Type=TimeDependent/LoadCaseScaleFactor=1.0/Apply创建非空间场Field/Action=create/Object=nonspatial/Method=TabularInput/FieldName=freq/ActiveIndependentVariables=Frequency/Inputdata/f-1=1/value=1/f-2=200/value=1/OK/Apply创建位移约束及单位正弦载荷。车架L,F端固定，A点加单位

10、正弦激励Loads/BCs/Action=Create/Object=Displacement/Type=Nodal/NewSetName=fix/inputDataTranslations=/Rotations=/OK/SelectAppli.Select=Geometry/ApplicationRegion=Surface1、5/Add/OK/ApplyLoads/BCs/Action=Create/Object=Force/Type=Nodal/NewSetName=force1/InputDataLoad/BCSetScaleFactor=1.0/Force=/Time/Freq.De

11、pendence=f:freq/Ok/SelectApplicationRegionSelect=FEM/ApplicationRegion/SelectNodes=Node43760(NodeA)/Add/Ok/Apply定义分析类型并设置分析参数Analysis/Action=Analyze/Object=EntireModel/Method=FullRun/Jobname=frequency/SolutionTypeSolutionType=FREQUNCYRESPONSE/Formulation=Direct/SolutionPara.Struct.DampingCoeff.=0.00

12、3/OK/OK定义分析工况Subcases/SubcaseName=case1/SubcasePara.DEFINEFREQUENCIES.StartFreq.=0;EndFreq=300;No.Incr=300/OK/OK/OutputRequestsOutputRequests=DISPLACEMENT;ACCELERATION/OK/Apply/Cancel提交分析工况SubcaseSelect.SubcaseSelected=case1/OK/Apply读取计算结果并观察频率响应函数图像Action=AccessResults/Object=AttachXDB/Method=Resul

13、tEntities/selectresultsfiles=frequency.xdb/ApplyResults/Action=Create/Object=Graph/SelectResultCases=case1.-filter/Apply/SelectYResult=Accelerations/Displacements/Quantity=Magnitude/TargetEntities/SelectNodes=NodeA、G/Apply3.瞬态分析1)打开备份文件frequency.db进行瞬态分析File/open/文件名=time.db创建载荷工况Load/BCs/CreateLoad

14、Cases/Action=Create/LoadCaseName=case2/MarkCurrent(选中)/Type=TimeDependent/LoadCaseScaleFactor=1.0/Apply创建非空间场Field/Action=create/Object=nonspatial/Method=TabularInput/FieldName=time/ActiveIndependentVariables=Time/Inputdata/t-1=0/value=0/t-2=0.0015/value=1/t-3=0.003/value=0/t-4=0.01/value=0/OK/Apply

15、创建位移约束及三角脉冲载荷。车架L,F端固定，A点加三角脉冲激励Loads/BCs/Action=Create/Object=Displacement/Type=Nodal/NewSetName=fix/inputDataTranslations=/Rotations=/OK/SelectAppli.Select=Geometry/ApplicationRegion=Surface1、5/Add/OK/ApplyLoads/BCs/Action=Create/Object=Force/Type=Nodal/NewSetName=force2/InputDataLoad/BCSetScaleFa

16、ctor=1.0/Force=/Time/Freq.Dependence=f:time/Ok/SelectApplicationRegionSelect=FEM/ApplicationRegion/SelectNodes=Node43760(NodeA)/Add/Ok/Apply定义分析类型并设置分析参数。Analysis/Action=Analyze/Object=EntireModel/Method=FullRun/Jobname=time/SolutionTypeSolutionType=TRANSIENTRESPONSE/Formulation=Direct/OK定义分析工况。Subc

17、ases/SubcaseName=case2/SubcasePara.DEFINETIMESTEPS.No.ofTimeSteps.=400;Delta-T=0.0005/OK/ModalDamping=Crit.Damp.(CRIT)/DEFINEMODALDAMPING/Frequency=0,Value=0.003/Frequency=500.Value=0.003/OK/OK/OutputRequestsOutputRequests=DISPLACEMENT;ACCELERATION/OK/-Apply-/Cancel提交分析工况。SubcaseSelect.SubcaseSelect

18、ed=case2/OK/Apply读取计算结果并观察响应函数图像。Action=AccessResults/Object=AttachXDB/Method=ResultEntities/selectresultsfiles=time.xdb/ApplyResults/Action=Create/Object=Graph/SelectResultCases=case2.-filter/Apply/SelectYResult=Accelerations/Displacements/Quantity=Magnitude/TargetEntities/SelectNodes=NodeA、G/Apply

19、五、实验结果1.前十阶模态Mode1Mode2Mode3Mode4Mode6Mode7Mode8Mode9Mode102.频响分析LEGENDNode10602:Accelerations,Translational,MAGroUOQe_suel-SUOQeooov9.00+000-7.50+000-6.00+000-1.50+000-3.00+000-1.50+000-A点加速度耦合频响曲线LEGEND_euoQe_suel-SUOQe21.50+000-1.50+00050+0003.00+000-3.00+00050+000A点加速度X方向频响曲线LEGEND .00-005.00-00

20、4.0IMICH3.00-002.00-001.00-00_euoQe_suel-S4Uujoe_dsoLEGENDA点位移耦合频响曲线6.00-004.50-0CH3.00-00-3.00-001.50-00-1.50-00_euoQe_sueJ_-srEoe_dsQA点位移X方向频响曲线LEGEND9.00+0007.50+0006.00+0001.50+0003.00+0001.50+0000.5.00+0011.00+0021.50+0022.00+0022.50+0023.00+002FrequencyNode9077:Accelerations,Translational,MAGcuUOQe_suel-suo一ro00ovG点加速度耦合频响曲线LEGENDeuoQesuel-SUOQe28.00-00-6.00-001-00-0CM-2.00-0CM-0.-2.00-0CM-400-00!o.5.00+0011.00+0021.50+0022.00+0022.50+0023.00+002FrequencyG点位移X方向频响曲线3.瞬态分析（取0.003阻尼比）G点加速度X方向频响曲