ansys可以实现用力场来约束薄面么？

我想研究薄面在曲率下的弹性能，就用了个力场想把他压到一个虚幻的球上，实际上好像报了约束不足。程序如下

/PREP7

ET,1,SHELL63

mp,ex,1,100

mp,prxy,1,0.3

r,1,0.001

CYL4,,,0.1

AESIZE,1,0.01

AMESH,1

finish

/solu

press=10000

asel,all

esla,s

nsla,s,1

ANTYPE,STATIC

NSUBST,100,1000,1,off

dofsel,s,fx,fy,fz

*get,enmax,elem,,num,max

fcum,add 

*do,i,1,enmax

*if,esel,eq,1,then

*get,ae,elem,i,area 

xe=centrx 

ye=centry 

ze=centrz 

p_e=sqrt((xe-1)*(xe-1)+ye*ye+ze*ze-1)*press

f_tot=p_e*ae

esel,s,elem,,i

nsle,s,corner

*get,nn,node,,count

f_n=f_tot/nn

*do,j,1,nn

f,nelem(i,j),-fz,f_n 

f,nelem(i,j),-fx,f_n 

f,nelem(i,j),-fy,f_n 

*enddo

*endif

esla,s

*enddo

fcum,repl

dofsel,all

allsel

solve

finish

/POST1

PLDISP,all

为什么没法出结果，是哪里写错了还是ansys 没法实现