AUTODYN-Chapter-3-AUTODYN-基础理论

3-1ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665第三章AUTODYN基础理论ANSYSAUTODYNAUTODYNBasics3-2ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual结构和非结构化Parts(网格)•一个AUTODYNPart能使用结构化或者非结构化网格–结构化网格可以在AUTODYN中生成•使用(I,J,K)指标空间–非结构化网格必须从外部导入(例如从Workbench)•拉格朗日Parts(实体,壳,梁)–既可以用结构化网格也可以非结构化网格–非结构化网格求解起来更加有效(效率更高)•在求解之前，一个结构化网格可以转换成非结构化网格–拉格朗日Parts(结构或者非结构)能够使用“fill”功能填充到Euler和SPHParts中•Euler和ALEParts–均为结构化–Euler网格通常都是直线正交的AUTODYNBasics3-3ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManualiji=1i=11j=1j=6结构化Parts-指标空间•AUTODYN中每一个结构化Part都会定义一个指标空间，2D(i,j)或者in3D(i,j,k),这里i,j和k是从1到Ni,Nj,Nk的整数–指标空间都是正交的AUTODYNBasics3-4ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManualxyi=1i=11j=1j=6结构化Parts-物理空间•每一个结构化part还有一个物理空间xyz-空间,这里x,y和z是实数–物理空间中网格通常有一定的形状AUTODYNBasics3-5ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual指标空间物理空间UnusedElements•并不是多有在指标空间定义的单元都会在物理空间中使用–没有赋予材料的单元是Unused–这个功能允许对负责体进行建模结构化Parts–指标空间删除单元-Unused功能AUTODYNBasics3-6ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual•通过PartWizard可以自动生成高质量的结构化Parts为我们预先定义的几何体–2D体•Box,Quad,Circle,Ogive,Rhombus,Triangle,Wedge–3D体•Box,Hex,Cylinder,Sphere,Ogive,Fragments/Bricks–壳•Plate,Cylinder•手动建立高质量的结构化网格–点–线–面–体•外部导入结构化网格–ICEM-CFD–TrueGridPartWizard创建结构化PartsAUTODYNBasics3-7ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManualPart向导GeometryZoningFill•Part向导建模三部曲–定义预定义几何体–定义指标空间–填充partsAUTODYNBasics3-8ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManualPart向导–2D正方形AUTODYNBasics3-9ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManualPart向导–2D圆形AUTODYNBasics3-10ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManualOgiveQuadsPart向导–2D模型WedgeRhombusAUTODYNBasics3-11ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManualPart向导–3D正方体AUTODYNBasics3-12ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManualPart向导–3D圆柱AUTODYNBasics3-13ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManualSphereBricks/FragmentsHexOgivePart向导–3D模型AUTODYNBasics3-14ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual平板圆柱Part向导–3D壳AUTODYNBasics3-15ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual•使用下面步骤一步一步生成网格–点–线–面–体•插值•拉伸手动建模AUTODYNBasics3-16ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual•ANSYS,ICEM-CFD–强大的3D六面体网格生成–全面的CAD接口•CATIA,Pro/Engineer,SDRCI-DEAS,SolidWorks,Unigraphics,….–ICEM-CFD结构化(映射)网格输入接口•ICEMmultiblock网格(.geo文件)•TrueGrid输入和ICEM相同输入3D结构化AUTODYNBasics3-17ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual•分别在材料和初始条件面板中定义材料和初始条件•定义以后,材料和初始条件就能够在PartWizard建模过程中通过Fill选项给part填充材料和初始条件.DefineApplyApply(PartWizard)材料和初始条件AUTODYNBasics3-18ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual用材料和初始条件填充partsAdditionalBlockFills•Wizard中每一个part用一种材料填充•Wizard完成以后可以进行附加的填充–每一个附加填充可以替换前一个填充的材料和初始条件•如果中心在填充区域的内部Lagrange单元可以被填充(没有多物质填充功能)AdditionalGeometryFillWizardFillAUTODYNBasics3-19ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual•边界条件被定义从Boundaries对话框•一旦被定义,通过parts中对话面板中的Boundary选项就可以将边界条件施加给结构化网格边界条件DefineApplyAUTODYNBasics3-20ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual•边界条件既可以定义在已使用网格的外表面也可以定义在未使用网格的外表面•默认的边界条件是:–Lagrange:自由边界(压力=0.0)–Euler:刚性墙(无流动,速度=0.0)Unused单元被填充单元定义了边界条件的位置边界条件AUTODYNBasics3-21ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManualConstanttTrapezoidtTriangulartExponentPk=Pe-kttUsersubroutineEXSTRt•应用到LagrangePartsPiecewiset应力边界条件AUTODYNBasics3-22ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual•应用到Lagrange,ALE,Shell,Beam和SPHParts–X,Y,Z速度约束•常数–速度定义为一个常数•界限–定义上下限–在ExplicitDynamics中定义位移约束•分段函数–分段线性函数–总体速度约束•定义X,Y,Z(3D)速度和转动速度为常数–用户子程序EXVEL•用户定义随时间变化的X,Y,Z速度速度边界条件AUTODYNBasics3-23ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual•应用到BeamParts–节点力边界条件•常数,分段函数,用户子程序EXFOR•x,y,z和总体方向–单元力/单位长度边界条件•常数,分段函数,用户子程序EXFOR•x,y,z和总体方向边界条件:力AUTODYNBasics3-24ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February27,2009Inventory#002665TrainingManual•应用到Lagrange,ALE和EulerParts–传输波通过单元面–只有正交分量被传输–可以定义边界的阻抗•如果阻抗被设置为0，那么临近单元的阻抗将被应用–传输边界是近似边界条件，尽量远离计算的关键区域定义–对于空气中爆炸的欧拉算法,推荐使用压力为0的流出（Outflow）边界条件cI边界条件:传输边界AUTODYNBasics3-25ANSY