板优化的问题？

cyh3278

板优化时老是出错，目标函数几乎都是不变的。
以下是建模和提取参数的宏文件：
plane.mac如下：
LENGTH=200
YOUNG=2.07e5
THICKNESS=30
!FORCE=1000
!DENSITY=9.0E-6
/PREP7
ET,1,SHELL63
!ET,1,82,,,3
MP,EX,1,YOUNG
MP,NUXY,1,0.3
!MP,DENS,1,DENSITY
R,1,THICKNESS,THICKNESS,THICKNESS,THICKNESS
K,1,0
K,2,LENGTH,0
K,3,LENGTH,LENGTH
K,4,0,LENGTH
A,1,2,3,4
LSEL,S,LINE,,1,1
LSEL,A,LINE,,3,3
LESIZE,ALL,,,10
LSEL,S,LINE,,2,2
LSEL,A,LINE,,4,4
LESIZE,ALL,,,10
AMESH,ALL
FINI
/SOLU
NSEL,S,LOC,X,0,0
D,ALL,ALL
NSEL,S,LOC,X,LENGTH,LENGTH
D,ALL,ALL
NSEL,S,LOC,Y,0,0
D,ALL,ALL
NSEL,S,LOC,Y,LENGTH,LENGTH
D,ALL,ALL
ESEL,S,MAT,,1,1      !选定材料号为1的所有单元
SFE,ALL,1,PRES, ,10    !给选定的所有单元施加载荷
SOLVE
FINI
/POST1  
NSORT,S,EQV
*get,smax,sort,,max
!AVPRIN,0, ,
ETABLE,EVOL,VOLU,   
SSUM
*GET,VTOT,SSUM,ITEM,EVOL
FINI
以下是优化的命令流
/OPT
OPANL,'plane','mac',' '
OPVAR,THICKNESS,DV,20,40
OPVAR,SMAX,SV,,235
OPVAR,VTOT,OBJ, , ,1,  
OPTYPE,SUBP
OPFRST,40  
OPEXE   
OPLIST,ALL, ,0