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1、ABAQUS Standard基础教程 ElementSelectionCriteria Appendix1 ABAQUS Standard基础教程 内容提要 ElementsinABAQUSStructuralElements ShellsandBeams vs ContinuumElementsModelingBendingUsingContinuumElements用实体单元模拟弯曲StressConcentrations应力集中Contact接触IncompressibleMaterials不可压缩材料MeshGeneration网格生成SolidElementSelectionSum
2、mary ABAQUS Standard基础教程 ElementsinABAQUS ABAQUS Standard基础教程 ElementsinABAQUS ABAQUS单元库中提供广泛的单元类型 适应不同的结构和几何特征ThewiderangeofelementsintheABAQUSelementlibraryprovidesflexibilityinmodelingdifferentgeometriesandstructures Eachelementcanbecharacterizedbyconsideringthefollowing 单元特性 Family单元类型Numberofno
3、des节点数Degreesoffreedom自由度数Formulation公式Integration积分 ABAQUS Standard基础教程 单元类型 Family Afamilyoffiniteelementsisthebroadestcategoryusedtoclassifyelements 同类型单元有很多相同的基本特 Elementsinthesamefamilysharemanybasicfeatures 同种类单元又有很多变化 Therearemanyvariationswithinafamily ElementsinABAQUS special purposeelement
4、slikesprings dashpots andmasses continuum solidelements shellelements beamelements rigidelements membraneelements trusselements infiniteelements ABAQUS Standard基础教程 ElementsinABAQUS Numberofnodes节点数 interpolation Anelement snumberofnodesdetermineshowthenodaldegreesoffreedomwillbeinterpolatedoverthed
5、omainoftheelement ABAQUSincludeselementswithbothfirst andsecond orderinterpolation 插值函数阶数可以为一次或者两次 ABAQUS Standard基础教程 ElementsinABAQUS 自由度数目DegreesoffreedomTheprimaryvariablesthatexistatthenodesofanelementarethedegreesoffreedominthefiniteelementanalysis Examplesofdegreesoffreedomare Displacements位移
6、Rotations转角Temperature温度Electricalpotential电势 ABAQUS Standard基础教程 公式FormulationThemathematicalformulationusedtodescribethebehaviorofanelementisanotherbroadcategorythatisusedtoclassifyelements Examplesofdifferentelementformulations Planestrain平面应变Planestress平面应力Hybridelements杂交单元Incompatible modeelem
7、ents非协调元Small strainshells小应变壳元Finite strainshells有限应变壳元Thickshells后壳Thinshells薄壳 ElementsinABAQUS ABAQUS Standard基础教程 积分Integration单元的刚度和质量在单元内的采样点进行数值计算 这些采样点叫做 积分点 Thestiffnessandmassofanelementarecalculatednumericallyatsamplingpointscalled integrationpoints withintheelement 数值积分的算法影响单元的行为Thenume
8、ricalalgorithmusedtointegratethesevariablesinfluenceshowanelementbehaves ABAQUS包括完全积分和减缩积分 ABAQUSincludeselementswithboth full and reduced integration ElementsinABAQUS ABAQUS Standard基础教程 Fullintegration 完全积分Theminimumintegrationorderrequiredforexactintegrationofthestrainenergyforanundistortedelemen
9、twithlinearmaterialproperties Reducedintegration 简缩积分Theintegrationrulethatisoneorderlessthanthefullintegrationrule ElementsinABAQUS ABAQUS Standard基础教程 ElementsinABAQUS Elementnamingconventions examples单元命名约定 B21 Beam 2 D 1st orderinterpolation CAX8R Continuum AXisymmetric 8 node Reducedintegration
10、 DC3D4 Diffusion heattransfer Continuum 3 D 4 node S8RT Shell 8 node Reducedintegration Temperature CPE8PH Continuum Planestrain 8 node Porepressure Hybrid DC1D2E Diffusion heattransfer Continuum 1 D 2 node Electrical ABAQUS Standard基础教程 ElementsinABAQUS ABAQUS Standard和ABAQUS Explicit单元库的对比Bothprog
11、ramshaveessentiallythesameelementfamilies continuum shell beam etc ABAQUS Standardincludeselementsformanyanalysistypesinadditiontostressanalysis 热传导 固化soilsconsolidation 声场acoustics etc AcousticelementsarealsoavailableinABAQUS Explicit ABAQUS Standardincludesmanymorevariationswithineachelementfamily
12、 ABAQUS Explicit包括的单元绝大多数都为一次单元 例外 二次 单元和四面体单元and二次beamelementsManyofthesamegeneralelementselectionguidelinesapplytobothprograms ABAQUS Standard基础教程 StructuralElements ShellsandBeams vs ContinuumElements ABAQUS Standard基础教程 StructuralElements ShellsandBeams vs ContinuumElements 实体单元建立有限元模型通常规模较大 尤其对
13、于三维实体单元如果选用适当的结构单元 shellsandbeams 会得到一个更经济的解决方案模拟相同的问题 用结构体单元通常需要的单元数量比实体单元少很多要由结构体单元得到合理的结果需要满足一定要求 theshellthicknessorthebeamcross sectiondimensionsshouldbelessthan1 10ofatypicalglobalstructuraldimension suchas ThedistancebetweensupportsorpointloadsThedistancebetweengrosschangesincrosssectionThewa
14、velengthofthehighestvibrationmode ABAQUS Standard基础教程 ShellelementsShellelementsapproximateathree dimensionalcontinuumwithasurfacemodel 高效率的模拟面内弯曲Modelbendingandin planedeformationsefficiently Ifadetailedanalysisofaregionisneeded alocalthree dimensionalcontinuummodelcanbeincludedusingmulti pointcons
15、traintsorsubmodeling 如果需要三维实体单元模拟细节可以使用子模型 Shellmodelofahemisphericaldomesubjectedtoaprojectileimpact StructuralElements ShellsandBeams vs ContinuumElements ABAQUS Standard基础教程 StructuralElements ShellsandBeams vs ContinuumElements Beamelements用线简化三维实体 Beamelementsapproximateathree dimensionalcontin
16、uumwithalinemodel 高效率模拟弯曲 扭转 轴向力 提供很多不同的截面形状截面形状可以通过工程常数定义 linemodel framedstructuremodeledusingbeamelements 3 Dcontinuum ABAQUS Standard基础教程 ModelingBendingUsingContinuumElements ABAQUS Standard基础教程 ModelingBendingUsingContinuumElements PhysicalcharacteristicsofpurebendingTheassumedbehaviorofthematerialthatfiniteelementsattempttomodelis 纯弯状态 Planecross sectionsremainplanethroughoutthedeformation 保持平面Theaxialstrain xxvarieslinearlythroughthethickness Thestraininthethicknessdirection yyiszeroif 0
