优化设计不成功

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finish
/clear
*afun,deg
filname,yhsj
/title,yhsj
*set,h,60
*set,b,60
*set,l,1000
/prep7
ET,1,beam3
r,1,b*h,b*h*h*h/12,h
mp,ex,1,2.1e5
mp,prxy,1,0.3
mp,dens,1,7.85e-6
WPCSYS,-1,0
csys,4
/VIEW,1,1,1,1
/AUTO,1
/REP,FAST
k,1,0,0,0
k,2,l,0,0
lstr,1,2
allsel
LESIZE,all,,,50
allsel
lmesh,all
/solu
allsel
Dk,1,ux
Dk,1,uy
Dk,2,ux
Dk,2,uy
allsel
SFbeam,all,1,PRES,5
allsel
solve
/post1
etable,e_vol,volu
ssum
*get,v_tot,ssum,,item,e_vol
nsort,u,y
*get,uy_min,sort,,min
uy_max=abs(uy_min)
finish
/filname,yhsj
/opt
opclr
finish
/clear
/input,yhsj,lgw
/opt
opanl,yhsj,low
opvar,b,dv,50,100,1
opvar,h,50,100,1
opvar,uy_max,sv,0,0.2,0.01
opvar,v_tot,obj,,,10000
opsave,yusj,opt
optype,first
opfrst,30
opexec
oplist,all
finish