请教各位高手一个问题

lzhouqi

下图是小弟在做大体积混凝土温度应力计算中，出现的错误，请问是哪个步骤出现问题呢？[img]file:///C:/DOCUME~1/ADMINI~1.327/LOCALS~1/Temp/M66P68FRHMBU7FBTCTN[YGJ.jpg[/img]

lzhouqi

“Large negative pivot value(-0.269305706) in Eqn.system.May be because of a bad temperature-dependent material property used in the model.

cayman

材料定义有问题？

lzhouqi

材料定义应该是没问题的，查了些资料，说单元形状有问题，我把命令流发过来，麻烦您给瞅瞅。这只是计算温度应力的，前面还有个计算温度场的。
fini
/clea
*set,day,70
*dim,exx,array,day
*do,k,1,day
t1=(24*k-1)/24
t2=24*k/24
ton=(t1+t2)/2
exx(k)=(1-exp(-0.28*(ton)**0.52))*3e10
*enddo
/prep7
et,1,solid45
*do,i,1,day
MP,DENS,1,2400
MP,EX,1,exx(i)
MP,prxy,1,0.167
MP,ALPX,1,0.9E-5
MP,REFT,1,0
*enddo

block,0,15,0,1,0,15
block,4,7,1,15,0,15
block,-2,17,0,-2,0,15
lsel,s,length,,19,19
lesize,all,,,38
lsel,s,length,,2,2
lesize,all,,,4
lsel,s,length,,15,15
lesize,all,,,30
lsel,s,length,,14,14
lesize,all,,,28
lsel,s,length,,3,3
lesize,all,,,6
lsel,a,length,,1,1
lesize,all,,,2
vmesh,1
vmesh,2
vmesh,3
numcmp,node
numcmp,elem
allsel
vsel,s,,,1,2
nslv,s,1
*get,n_num,node,,count
allsel
dtran

allsel
*get,n_num,node,,count
*dim,ttt,array,n_num

/solu
allsel
nsel,s,loc,y,0
d,all,ALL
allsel
*do,i,1,day
*vread,ttt(1),temp,txt,,,,,,(i-1)*n_num
(f15.10)
*do,j,1,N_num
bf,i,temp,ttt(j)
*enddo
allsel
vsel,s,,,1,2
eslv,s
mpchang,I,all
allsel
solve
*enddo

/post1
ttt(1)
*do,i,1,day
set,I
*CFOPEN,x,TXT,,append
*do,j,1,n_num
*GET,SX,NODE,j,s,x
*vwrite,sx+ttt(j)
(f25.15)
*enddo
*cfclos
*vread,ttt(1),x,txt,,,,,,(i-1)*n_num
(f25.15)
*enddo
*cfclos
fini