关于自定义多种材料截面时出现的问题

kanghui

自己做了一个钢管混凝土截面的定义，结果程序提示错误！我看不明白！请各位高手指点finish
/clear
/prep7
Ro=0.25
Ri=0.24
csys,1
cyl4,,,ri
cyl4,,,ro
aptn,all
wprota,,90
asbwa,all
wprota,,,90
asbw,all
wpcsys
et,1,plane82
mymat1=4
mymat2=7
mp,ex,mymat1,1.0
mp,ex,mymat2,1.0
asel,s,loc,x,0,ri
aatt,mymat1,,1
asel,s,loc,x,ri,ro
aatt,mymat2,,1
allsel
esize,0.01
mshape,0,2d
mshkey,1
amesh,all
secwrite,mycsolid,sect

finish
/clear
/prep7
et,1,beam189
mym1=4
mym2=7
mp,ex,mym1,3.0e10
mp,prxy,mym1,0.167
mp,dens,mym1,2600
mp,ex,mym2,2.1e11
mp,prxy,mym2,0.3
mp,dens,mym2,8000
sectype,1,beam,mesh
secread,mycsolid,sect,,mesh
当执行到 aatt,mymat2,,1 时程序提示说“there are no selected unmeshedareas.this command is ignored."   为什么？
当我让 Ri=0.2 时 程序就可以执行了。为什么？