mesh study

网格划分的控制主要考虑以下三个因素：（1）单元形状（elementshape）（2）中节点的设置(midsidenodeplacement)（3）单元尺寸（elementsize）现在分别加以说明：◎单元形状：对于2d的面的划分，可以采用三角形单元或者四边形单元。对于3D的体的划分，要么采用六面体单元，要么采用四面体单元。二者的混合使用一般不推荐使用。若采用(transitionalpyrmidelement)过渡的金字塔单元，可以采用二者的混合使用。◎中间节点设置的控制（controlingplacementofmidsidenodes）ANSYS默认情况下，将具有中节点的单元的中节点设置在边界线上或边界的面上。◎单元尺寸的设置（1）对于采用free方式的smartelementsizing(smrtsize)方法：该方法具有如下优点：首先计算面或体中线的单元边的尺寸；其次，若采用四边形单元，所有边的划分为偶数。smrtsize控制方法：basic，简单的设置划分等级(level),1(finemesh)~10(coarsemesh)。Advacedcontrol,可以控制划分的质量，使网格尽可能的满足要求。（2）对于采用mapped方式的默认的单元尺寸（defaultelementsize）通过命令：desize来修改采用mapped方式在每一条线上划分份数。对于大型模型，首先查看模型的划分是很有必要的：例如Et,1,45Mshape,0Mshkey,1Lesize,allLplot改变单元尺寸：Desize…..Lesize,all,,,,,1Lplot（3）局部网格控制I.esize(整体尺寸控制)，可以采用面或体中最短线之间的距离（一般划分2~3个单元），来控制整体单元尺寸II.kesize（指定点控制）III.lesize（指定线控制）。上述方法可以联合使用，若指定相互冲突，ANSYS根据以下优先级来确定划分的数量：Lesizekesizeesize（4）内部网格的控制（interiormeshcontrol）以上所述均为通过边界来控制单元的尺寸,也可以通过内部的面或体来控制单元的尺寸,通过mopt来实现。I.mopt,expand：作用从边界的细分到内部的粗分。II.mopt,trans,value:实现从边界上小的单元到内部的单元尺寸的过渡（与(1)联合应用）III.mopt,aorder,on：在多个体划分网格时，为了保证小的面上的单元数和相对较高的质量，采用此命令，保证首先在较小的面上划分网格。问题1一空心半球体，其内半径为1500mm，外半径为2000mm。现要沿其径向粘贴CFRP(Ex=235000Mpa,Ey=2000Mpa,u=0.3),沿环向粘贴GFRP(Ex=150000Mpa,Ey=1000Mpa,u=0.3)。球体采用solid45单元，CFRP和GFRP均采用shell41单元，CFRP与GFRP与球体完全粘结(即节点重合)，且CFRP与GFRP间隔粘贴，其水平投影如图所示。如何建立其有限元模型，请各位附上各自的命令流。要求：尽量用mappedmesh.沿环向分成36个单元，沿厚度方向分成2个单元，沿径向分成5个单元。并求其承载能力在粘贴CFRP和GFRP前后改变多少？条件没给全：1、cfrp和gfrp的各向异性的材性没给全，只好随便猜了。2、cfrp和gfrp的厚度没给，只好随便取了0.1mm。3、半球体的材性没给，随便取了一个值。4、既然是弹性分析，何来“承载能力”之说？模型建好了，命令流如下，还没仔细检查，请指正。fini/clear,start/prep7/uis,msgpop,3!不显示任何警告!定义局部坐标系LOCAL,12,2,0,2,0,,90,,1,1,!定义单元、材性et,1,41et,2,45r,1,0.0001!假设FRP厚0.1mmmp,ey,1,235e9!CFRP的材性(注意此处为ey)mp,ex,1,2e9mp,ez,1,2e9mp,prxy,1,0.03mp,pryz,1,0.3mp,prxz,1,0.03MP,GXY,1,100E9MP,GYZ,1,100E9MP,GXZ,1,100E9!1.0-prxy**2*ey/ex-pryz**2*ez/ey-prxz**2*ez/ex-2.0*prxy*pryz*prxz*ez/ex>0mp,ex,2,150e9!GFRP的材性mp,ey,2,1e9mp,ez,2,1e9mp,prxy,2,0.3mp,pryz,2,0.3mp,prxz,2,0.3MP,GXY,2,50E9MP,GYZ,2,50E9MP,GXZ,2,50E9mp,ex,3,200e9!假设半球的材性mp,prxy,3,0.3!建半球剖面并分网*do,i,1,10CYL4,0,0,1.5,(i-1)*9,1.75,i*9CYL4,0,0,1.75,(i-1)*9,2,i*9*enddoaglue,allLESIZE,all,,,1,,,,,0amesh,all!旋转成半球体EXTOPT,ESIZE,1,0EXTOPT,ACLEAR,1TYPE,2MAT,3VROTAT,all,,,,,,75,78,360,36CM,qiu,volu!定义一个叫“球”的组!建GFRPcsys,0ASEL,s,LOC,y,sin(18/180*3.14159)*2,sin(36/180*3.14159)*2ASEL,a,LOC,y,sin(54/180*3.14159)*2,sin(72/180*3.14159)*2csys,2ASEL,r,LOC,x,2,3CM,gfrp,area!定义一个叫“GFRP”的组csys,0TYPE,1MAT,2real,1amesh,all!建CFRPallsel,allCSYS,12,ASEL,s,LOC,y,0,10*do,i,3,36,2ASEL,a,LOC,y,(i-1)*10,i*10*enddocsys,2ASEL,r,LOC,x,2,3csys,0CM,temp,AREAAGEN,2,all,,,0,0,0,,1CMSE,U,tempCM,cfrp,area!定义一个叫“CFRP”的组TYPE,1MAT,1real,1LESIZE,all,,,1,,,,,0amesh,all!耦合allsel,allcpintf,all/solu!加约束ASEL,s,LOC,y,0,0da,all,uy!加荷载csys,2ASEL,s,LOC,x,0,1.5csys,0SFA,all,1,PRES,1000!假设荷载为1000牛/m^2/PSF,PRES,NORM,2,0,1allsel,all!solve问题二设计思路：其实ansys的复制生成功能很强,如果能找到规律可以使问题大大简化版主能不能鼓励一下,给个分!别让我的积分总是零!哈哈/PREP7B1=5!X方向B2=5!Y方向B3=3!圆柱在z方向的定位B4=20!长方体的总长度CL1=8!大圆柱的高度CL2=5!小圆柱的高度R1=2!小圆柱的半径R2=3!大圆柱的半径ET,1,SOLID45K,1,0,0,0K,2,B1,0,0K,3,B1,B2,0K,4,0,B2,0K,14,0,0,-B3K,15,0,0,-(B3+CL1)K,16,0,0,-(B3+CL1+CL2)K,17,0,0,-B4L,1,14L,14,15L,15,16L,16,17CSYS,1K,5,R1,0,0K,6,R1,90,0K,7,R1,45,0K,8,R2,0,0K,9,R2,90,0K,10,R2,45,0K,11,R1*0.5,0,0K,12,R1*0.5,90,0K,13,R1*0.5,45,0L,6,7L,7,5L,9,10L,10,8CSYS,0A,1,12,13,11A,11,5,7,13A,13,7,6,12A,5,8,10,7A,7,10,9,6A,8,2,3,10A,10,3,4,9AGEN,2,6,7,1,0,0,-B3AGEN,2,4,7,1,0,0,-(B3+CL1)AGEN,2,1,7,1,0,0,-(B3+CL1+CL2)!生成第一段体长度B3VDRAG,1,2,3,4,5,6,1VDRAG,7,,,,,,1!生成大圆柱所在的体CL1VDRAG,8,9,,,,,2!生成小圆柱所在的体CL3VDRAG,10,11,12,13,,,3!生成另外异端的体VDRAG,14,15,16,17,18,19,4VDRAG,20,,,,,,4CSYS,1VGEN,2,1,20,1,0,90,0ESIZE,,4VMESH,ALL问题五，圆球顶柱身/PREP7K,1,1,0,0,K,2,0,1,0,K,3,0,0.9,0,K,4,.9,0,0,K,5,0,0,0,K,6,1,-1.5,0,K,7,0.9,-1.5,0,LARC,1,2,5,1,!!line1LARC,4,3,5,.9,!!line2L,4,7!!line3L,7,6!!line4L,6,1!!line5L,2,3!!line6L,4,1!!line7AL,1,6,2,7AL,3,4,5,7APLOTFLST,2,2,5,ORDE,2FITEM,2,1FITEM,2,-2FLST,8,2,3FITEM,8,3FITEM,8,5VROTAT,P51X,,,,,,P51X,,360,,ET,1,MESH200!*ET,2,SOLID95!*KEYOPT,1,1,7KEYOPT,1,2,0ASEL,S,LOC,Y,0FLST,5,4,5,ORDE,4FITEM,5,5FITEM,5,13FITEM,5,21FITEM,5,29CM,_Y,AREAASEL,,,,P51XCM,_Y1,AREACHKMSH,'AREA'CMSEL,S,_Y!*AMESH,_Y1!*CMDELE,_YCMDELE,_Y1CMDELE,_Y2!*ALLSEL,ALLFLST,5,8,6,ORDE,2FITEM,5,1FITEM,5,-8CM,_Y,VOLUVSEL,,,,P51XCM,_Y1,VOLUCHKMSH,'VOLU'CMSEL,S,_Y!*VSWEEP,_Y1!*CMDELE,_YCMDELE,_Y1CMDELE,_Y2问题六finish/clear/filname,rt!*r=37.3/prep7et,1,63r,1,0.1mp,ex,1,10e6mp,nuxy,1,0.3mp,dens,1,0.1/386.1pcirc,0,rcsys,1k,5,28.3,11.25local,11,0,27.75622,5.521056,0,11.25csys,11k,6,,2.25k,7,,-2.25k,8,7.08545,3.45k,9,7.08545,-3.45k,10,8.5,1k,11,8.5,-1k,12,20,1k,13,20,-1al,1,2,3,4a,5,6,8,10,12,13,11,9,7aovlap,1,2adele,3,,,1csys,1agen,16,4,,,,22.5aovlap,all/pnum,area,1/replotcsys,1k,200,24.2857,88.5k,201,24.2857,49.5k,202,24.2857,10.5k,203,27.15,88.5k,204,27.15,49.5k,205,27.15,10.5csys,0k,206,24.4610,1.5k,207,27.3835,1.5l,200,201l,201,202l,202,206l,206,207l,207,205l,205,204l,204,203l,203,200lfillt,4,20,0.5lfillt,51,20,0.5al,69,87,2,3,60,4,51,96,105,20arsym,x,5arsym,y,5,7,2aovlap,27,5,7,8,9adele,5adele,7,9,1adele,1