[交流] 【讨论】壳单元和实体单元建模 计算结果差距太大 咋回事？ 已有1人参与

大家好：    小弟最近做了一个圆柱双大开孔的项目，因为用实体建模在锐角部分网格不好划分，网格容易出现扭曲，故用壳单元建模。    文献《用壳单元进行30°斜开孔不强计算的可行性研究》提到，壳单元建立的模型是按接管和壳体以及它们相交的点划线部分建立的,壳单元模型与实体模型在相交部位有较大的出入,壳单元模型把接管与筒体相交的三角形区域简化为两个相互分离的壳体,在相交部分以外的区域,两种模型是一致的。在用有限元分析法进行30°斜开孔补强计算时,只要根据壳单元模型的特点,选取适当的评估位置,那么用壳单元模型得到的计算结果完全满足工程要求。30°斜开孔计算是壳单元模型与实体单元模型相差最大的一种,既然壳单元模型在这一类开孔的计算上满足工程要求,那么壳单元模型在其他形式的开孔计算中,必然有更高精度的结果。     我的壳单元建模时，预先将相交部位分割出来。计算完以后将相交部分的应力不予显示，同时与实体单元进行比较。发现计算结果差距是相当的大。请各位高手帮我分析一下原因和提出建议！多谢多谢！ 壳单元命令流 finish /clear /filn,modle006 /title,modle006 pc=3.95！内压 D=2132  ！筒体中直径 T=32 di=D-T    do=D+T      !筒体外径 L=8000 k1=0.7 !对管1的开孔率 k2=0.7   !对管2的开孔率 m1=3.125  !对管1的壁厚比 m2=3.125     !对管2的壁厚比 t1=T*m1 t2=T*m2 d1=D*k1            !管1中半径 d1i=d1-t1         !管1内径 d1o=d1+t1         !管1外径 d2=D*k2            !管2中半径 d2i=d2-t2         !管2内径 d2o=d2+t2         !管2外径 *afun,deg ang1=asin((d1+t1/2)/d) ang2=30 ang3=asin((d2+t2/2)/d) h1=1485      h2=1485 !模型中建立的管子长度 paxi=-pc*di**2/(do**2-di**2)   ！轴向平衡力 paxi1=-pc*d1i**2/(d1o**2-d1i**2) paxi2=-pc*d2i**2/(d2o**2-d2i**2) /prep7                ！前处理 et,1,shell63 mp,ex,1,2e5 mp,nuxy,1,0.3 mp,dens,1,7.85e-9 mp,ex,2,1.91e5 mp,nuxy,2,0.3 mp,dens,2,7.85e-9 r,1,t r,2,t1 k,1,,, k,2,,,L K,3,D/2,, circle,1,d/2,2,3,360, lcomb,1,2,0 lcomb,3,4,0 l,1,2 adrag,1,3,,,,,2,,,,, wpcsys,-1,0 wpoff,,,l/2 wprota,,,90 csys,4 k,8,,, k,9,,,h1 l,8,9 K,10,d1/2,, circle,8,d1/2,9,10,360, adrag,9,10,11,12,,,8,,,,, wprota,,-ang1-ang2-ang3, csys,4 k,19,,, k,20,,,h2 l,19,20 K,21,d2/2,, circle,19,d2/2,20,21,360, adrag,22,23,24,25,,,21,,,,, circle,1,d/2+t/2,2,3,360, lcomb,34,35,0 lcomb,36,37,0 adrag,34,36,,,,,2,,,,, wpcsys,-1,0 wpoff,,,l/2 wprota,,,90 csys,4 circle,8,d1/2+t1/2,9,10,360, adrag,40,41,42,43,,,8,,,,, wprota,,-ang1-ang2-ang3, csys,4 circle,19,d2/2+t2/2,20,21,360, adrag,52,53,54,55,,,21,,,,, nummerg,all asel,s,,,1 asel,a,,,2 cm,neitong,area asel,s,,,11 asel,a,,,12 cm,waitong,area asel,s,,,7 asel,a,,,8 asel,a,,,9 asel,a,,,10 asel,a,,,3 asel,a,,,4 asel,a,,,5 asel,a,,,6 cm,neijieguan,area asel,s,,,13 asel,a,,,14 asel,a,,,15 asel,a,,,16 asel,a,,,17 asel,a,,,18 asel,a,,,19 asel,a,,,20 cm,waijieguan,area allsel asba,neitong,waijieguan,,,, allsel asba,neijieguan,waitong,,,, aptn,22,26,20,27,19 aptn,23,21,13,14,1,2 adele,19,,,1 adele,20,,,1 adele,26,,,1 adele,27,,,1 adele,32,,,1 adele,22,,,1 adele,11,,,1 adele,6,,,1 adele,3,,,1 adele,5,,,1 adele,4,,,1 wprota,,90, asbw,12 asbw,25 AGLUE,ALL wprota,,ang1+ang2+ang3, wprota,,-ang1-180*(2*T)/(3.1415926*di/2), asbw,4 wprota,,ang1+180*(2*T)/(3.1415926*di/2), wprota,,-ang1-ang2+180*(2*T)/(3.1415926*di/2), asbw,5 wprota,,-2*(ang3+180*(2*T)/(3.1415926*di/2)), asbw,3 wpcsys,-1,0 wpoff,,,l/2 wprota,,-90, wprota,,,ang1+180*(2*T)/(3.1415926*di/2) asbw,24 wpcsys,-1,0 wpoff,,,l/2 asbw,37 asbw,38 asbw,6 asbw,13 asbw,4 asbw,1 asbw,11 asbw,12 asbw,2 asbw,5 asbw,3 wpoff,,,d1/2+t+t1 asbw,all wpoff,,,-2*(d1/2+t1+t) asbw,all allsel asel,s,,,51 asel,a,,,56 asel,a,,,52 asel,a,,,58 asel,a,,,21 asel,a,,,19 asel,a,,,20 asel,a,,,14 cm,edge1,area    asel,s,,,50 asel,a,,,49 asel,a,,,57 asel,a,,,59 asel,a,,,12 asel,a,,,37 asel,a,,,26 asel,a,,,4 cm,edge2,area   asel,s,,,29 asel,a,,,28 asel,a,,,31 asel,a,,,30 asel,a,,,7 asel,a,,,8 asel,a,,,9 asel,a,,,10 cm,guan2,area asel,s,,,15 asel,a,,,16 asel,a,,,17 asel,a,,,18 asel,a,,,35 asel,a,,,33 asel,a,,,36 asel,a,,,34 cm,guan1,area asel,s,,,7 asel,a,,,8 asel,a,,,9 asel,a,,,10 asel,a,,,26 asel,a,,,4 asel,a,,,37 asel,a,,,12 cm,chuguan2,area asel,s,,,19 asel,a,,,14 asel,a,,,20 asel,a,,,21 asel,a,,,33 asel,a,,,34 asel,a,,,35 asel,a,,,36 cm,chuguan1,area allsel cmsel,u,edge1 cmsel,u,edge2 cmsel,u,guan1 cmsel,u,guan2 cm,guize,area allsel wpcsys,-1,0 wpoff,,,l/2 wprota,,,90 wpoff,,,h1 csys,4 lsel,s,loc,z,0 cm,gduan1,line          !接管1端面组件       allsel wpcsys,-1,0 wpoff,,,l/2 wprota,,,90 wprota,,-ang1-ang2-ang3, wpoff,,,h2 csys,4 lsel,s,loc,z,0 cm,gduan2,line        !接管2 端面组件 allsel cmsel,s,guize cmsel,a,edge1 cmsel,a,edge2 mat,1 real,1 esize,3*t mshape,0,2d amesh,all allsel cmsel,s,guan1 cmsel,a,guan2 mat,2 real,2 esize,3*t mshape,0,2d amesh,all allsel wpcsys,-1,0 /solu nsel,s,loc,z,0 d,all,ux d,all,uy d,all,uz d,all,rotx d,all,roty d,all,rotz nsel,s,loc,z,l *GET,n_total,NODE,0,COUNT sf,all,PRES,paxi/(n_total) allsel wpcsys,-1,0 wpoff,,,l/2 wprota,,,90 wpoff,,,h1 csys,4 nsel,s,loc,z,0 *GET,n_total1,NODE,0,COUNT sf,all,PRES,pax1i/(n_total1) allsel wpcsys,-1,0 wpoff,,,l/2 wprota,,,90 wprota,,-ang1-ang2-ang3, wpoff,,,h2 csys,4 nsel,s,loc,z,0 *GET,n_total2,NODE,0,COUNT sf,all,PRES,pax2i/(n_total2) allsel sfa,all,1,pres,pc alls solve save fini /post1 allsel cmsel,u,chuguan1 cmsel,u,chuguan2 wpcsys,-1,0 wpoff,,,l/2 asel,r,loc,z,0,8000 esla plnsol,s,int,0,1 实体单元命令流： finish /clear /filn,modle003 /title,modle003 pc=3.95！内压 D=2132  ！筒体中直径 T=32 di=D-T    do=D+T      !筒体外径 L=8000 k1=0.7 !对管1的开孔率 k2=0.7   !对管2的开孔率 m1=3.125  !对管1的壁厚比 m2=3.125     !对管2的壁厚比 t1=T*m1 t2=T*m2 d1=D*k1            !管1中半径 d1i=d1-t1         !管1内径 d1o=d1+t1         !管1外径 d2=D*k2            !管2中半径 d2i=d2-t2         !管2内径 d2o=d2+t2         !管2外径 *if,d1o,le,d2o,then d=d2o *else d=d1o *endif *afun,deg ang1=asin(d1o/di) ang2=45 ang3=asin(d2o/di) h1=1485      h2=1485 !模型中建立的管子长度 paxi=-pc*di**2/(do**2-di**2)   ！轴向平衡力 paxi1=-pc*d1i**2/(d1o**2-d1i**2) paxi2=-pc*d2i**2/(d2o**2-d2i**2) /prep7                ！前处理 et,1,45 mp,ex,1,2e5 mp,nuxy,1,0.3 mp,dens,1,7.85e-9 mp,ex,2,1.91e5 mp,nuxy,2,0.3 mp,dens,2,7.85e-9 wpcsys,-1,0 cyl4,,,di/2,,do/2,360,l   !筒体 wpcsys,-1,0 wpoff,,,l/2 wprota,,,90 cyl4,,,d1i/2,0,d1o/2,360,h1  !第一个接管 wprota,,-ang1-ang2-ang3, cyl4,,,d2i/2,0,d2o/2,360,h2  !第二个接管 plot,all wpcsys,-1,0 wprota,,90, wpoff,,l/2, vsbw,1 vsbw,2 wprota,,,ang1+ang2+ang3 vsbw,3 allsel vptn,1,4,5,6 vptn,2,7,15,16 vdele,11,,,1 vdele,13,,,1 vdele,19,,,1 vdele,21,,,1 vdele,1,,,1 vdele,18,,,1 vdele,3,,,1 vdele,8,,,1 wpcsys,-1,0 wpoff,,,l/2 vsbw,all wpoff,,,d/2+T vsbw,all wpoff,,,-2*(d/2+T) vsbw,all wpcsys,-1,0 wpoff,,,l/2 wpcsys,-1,0 wprota,,90, wpoff,,l/2, wprota,,,ang1+180*(T/2)/(3.1415926*di/2) vsbw,4 vsbw,14 vsbw,12 vsbw,22 wpcsys,-1,0 wprota,,90, wpoff,,l/2, wprota,,,ang1+ang2-180*(T/2)/(3.1415926*di/2) vsbw,24 vsbw,29 vsbw,30 vsbw,31 wpcsys,-1,0 wprota,,90, wpoff,,l/2, wprota,,,-ang1-180*(T/2)/(3.1415926*di/2) vsbw,9 vsbw,10 vsbw,17 vsbw,20 wpcsys,-1,0 wprota,,90, wpoff,,l/2, wprota,,,ang1+ang2+2*ang3+180*(T/2)/(3.1415926*di/2) vsbw,9 vsbw,36 vsbw,17 vsbw,38 lcomb,256,230,0 lcomb,255,229,0 lcomb,184,207,0 lcomb,183,206,0 lcomb,192,215,0 lcomb,191,214,0 lcomb,265,242,0 lcomb,266,243,0 wpcsys,-1,0 csys,1 asel,s,loc,x,di/2 asel,u,,,30 asel,u,,,56 asel,u,,,181 asel,u,,,173 asel,u,,,68 asel,u,,,70 asel,u,,,20 asel,u,,,65 asel,a,,,100 asel,a,,,79 asel,a,,,96 asel,a,,,100 asel,a,,,105 asel,a,,,110 asel,a,,,106 asel,a,,,17 asel,a,,,113 asel,a,,,2 asel,a,,,14 asel,a,,,68 asel,a,,,20 asel,a,,,48 asel,a,,,61 asel,a,,,34 asel,a,,,46 asel,a,,,119 asel,a,,,122 cm,inner-press,area     !建立内压面组分 allsel wpcsys,-1,0 vsel,s,loc,z,0,l/2-d/2-T vsel,a,loc,z,l/2+d/2+T,l vsel,a,,,29 vsel,a,,,30 vsel,a,,,20 vsel,a,,,36 aslv lsla vplot cm,guize,volu allsel vsel,s,,,37 vsel,a,,,39 vsel,a,,,12 vsel,a,,,14 aslv lsla vplot cm,edge1,volu allsel vsel,s,,,34 vsel,a,,,40 vsel,a,,,42 vsel,a,,,35 aslv lsla vplot cm,edge2,volu allsel vsel,s,,,16 vsel,a,,,25 vsel,a,,,19 vsel,a,,,3 vsel,a,,,18 vsel,a,,,15 vsel,a,,,21 vsel,a,,,26 aslv lsla vplot cm,guan1,volu allsel vsel,s,,,7 vsel,a,,,2 vsel,a,,,28 vsel,a,,,6 vsel,a,,,27 vsel,a,,,13 vsel,a,,,5 vsel,a,,,11 vsel,a,,,1 vsel,a,,,8 aslv lsla vplot cm,guan2,volu wpcsys,-1,0 wpoff,,,l/2 wprota,,,90 wpoff,,,h1 csys,4 asel,s,loc,z,0 cm,gduan1,area           !接管1端面组件       allsel wpcsys,-1,0 wpoff,,,l/2 wprota,,,90 wprota,,-ang1-ang2-ang3, wpoff,,,h2 csys,4 asel,s,loc,z,0 cm,gduan2,area        !接管2 端面组件 lsel,s,length,,0,t lesize,all,,,3,,,,,1 lsel,a,length,,0,t1 lesize,all,,,3,,,,,1 lsel,a,length,,0,t2 lesize,all,,,3,,,,,1 allsel lesize,184,,,8,,,,,1 lesize,183,,,8,,,,,1 lesize,204,,,8,,,,,1 lesize,205,,,8,,,,,1 lesize,3,,,8,,,,,1 lesize,6,,,8,,,,,1 lesize,212,,,8,,,,,1 lesize,213,,,8,,,,,1 lesize,191,,,8,,,,,1 lesize,192,,,8,,,,,1 lesize,227,,,4,,,,,1 lesize,12,,,4,,,,,1 lesize,241,,,4,,,,,1 lesize,240,,,4,,,,,1 lesize,4,,,2,,,,,1 lesize,5,,,1,,,,,1 lesize,218,,,2,,,,,1 lesize,217,,,1,,,,,1 lesize,232,,,2,,,,,1 lesize,233,,,1,,,,,1 lesize,252,,,2,,,,,1 lesize,253,,,1,,,,,1 lesize,113,,,1,,,,,1 lesize,114,,,1,,,,,1 lesize,173,,,1,,,,,1 lesize,174,,,1,,,,,1 lesize,176,,,6,,,,,1 lesize,175,,,6,,,,,1 lesize,111,,,6,,,,,1 lesize,112,,,6,,,,,1 allsel mat,1 cmsel,s,guize vsweep,all allsel mat,2 cmsel,s,guan1 vsweep,all allsel mat,2 cmsel,s,guan2 vsweep,7 vsweep,8 vsweep,2 vsweep,1 vsweep,28,83,117 vsweep,27,117,82 vsweep,6,6,69 vsweep,11,69,60 vsweep,13,60,64 vsweep,5,64,5 mat,1 cmsel,s,edge1 vsweep,12,128,42 vsweep,39,169,59 vsweep,37,162,161 vsweep,14,53,52 mat,1 cmsel,s,edge2 vsweep,42,183,182 vsweep,35,151,152 vsweep,34,149,150 vsweep,40,176,175 /solu allsel wpcsys,-1,0 asel,s,loc,z,0 da,all,ux da,all,uy da,all,uz asel,s,loc,z,l sfa,all,1,pres,paxi allsel cmsel,s,gduan1 sfa,all,1,pres,paxi1 allsel cmsel,s,gduan2 sfa,all,1,pres,paxi2 cmsel,s,inner-press sfa,all,1,pres,pc allsel solve save fini /post1 plnsol,s,int,0,1 wpcsys,-1,0 wpoff,,,l/2 vsel,s,loc,z,0,8000 eslv nsle plnsol,s,int,0,1

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