哪位大神帮我看看下面的程序

哪位大神帮我看看下面的程序，我想通过改变时间time来改变移动载荷的速度结果为什么不对啊！很是苦恼！ *SET,LONG,80 !梁长度为80米，即LONG=80*SET,NE,80 !单元数为80
*SET,DL,LONG/NE
*SET,VV,120 !移动速度
*SET,DT,DL/VV*3.6
/solu
antype,trans
trnopt,full
timint,on
nlgeom,on
sstif,on
nropt,full
outres,all,all
autots,on
estif,1e-12
esel,s,elem,,99,658
ekill,all
allsel,all
time,DT
nsubst,4,8
kbc,1
esel,s,elem,,99,104
esel,a,elem,,579
ealive,all
nsel,s,node,,95,410
d,all,all
allsel,all
d,91,ux
d,92,ux
d,93,ux
d,94,all
f,91,fy,296
ACEL,0,9800,0
solve
*get,disp(1,1),node,3,u,y
*get,disp(1,2),node,91,u,y
*do,i,0,77
time,DT+DT*i
nsubst,4,8
kbc,1
allsel,all
fdele,all,all
esel,s,elem,,99+6*i,104+6*i
esel,a,elem,,579+i
ekill,all
esel,s,elem,,105+6*i,110+6*i
esel,a,elem,,580+i
ealive,all
nsel,s,node,,91,410
ddele,all,all
nsel,u,node,,95+4*i,98+4*i
d,all,all
allsel,all
d,95+4*i,ux
d,96+4*i,ux
d,97+4*i,ux
d,98+4*i,all
f,95+4*i,fy,296
ACEL,0,9800,0
solve
*get,disp(2+i,1),node,4+i,u,y
*get,disp(2+i,2),node,95+4*i,u,y
*enddo
save
*status,disp