关于这方面工作,初步建议如下:
(1)初步的模拟最好先不要考虑混凝土下降段,不要考虑混凝土的压碎,同时单元尺寸不要过小,以免影响收敛。
(2)反复试算结果表明,混凝土的MISO和KINH模型、DP和MISES准则、剪力传递系数对模拟结果影响均不大,但在一定程度上影响了收敛性的好坏。
(3)当解决了收敛问题之后,最大的难点是下降段,对于一个桥墩(柱)的反复荷载试验,引起承载力下降的原因大体可归结为:塑性铰区混凝土压碎脱落、纵筋屈曲,对于以剪切破坏为主的试件,还包括剪切滑移的影响。对于以黏结破坏为主的试件,还包括纵筋-混凝土黏结滑移破坏。因此,能否正确模拟这些将是模型正确与否的关键。众所周知,以link8单元模拟钢筋自然无法模拟纵筋屈曲,这样就把一个因素忽略了。
/prep7
et,1,65
et,2,8
et,3,solid45
r,1
r,2,236e-6
r,3,75.4e-6
r,4,151.2e-6
mp,ex,1,2.522e10
mp,prxy,1,0.2
mp,dens,1,2500
tb,concr,1,1
tbdata,,0.5,0.95,5e6,-1
tb,miso,1,1,12
tbtemp,0
tbpt,,0.00068,17.15e6
tbpt,,0.00136,28.03e6
tbpt,,0.00204,33.62e6
tbpt,,0.00272,35.96e6
tbpt,,0.0034,36.53e6
tbpt,,0.00408,36.17e6
tbpt,,0.00476,35.35e6
tbpt,,0.00544,34.32e6
tbpt,,0.00612,33.214e6
tbpt,,0.0068,32.1e6
tbpt,,0.00748,31.02e6
tbpt,,0.00816,29.99e6
mp,ex,2,2.0e11
mp,prxy,2,0.28
tb,bkin,2
tbtemp,0
tbdata,,362e6,2e9
mp,EX,3,2.1E11
mp,PRXY,3,.27
tb,bkin,3
tbtemp,0
tbdata,,272.5e6,2.1e9
local,11,1,0,0,0,0,-90,0
csys,11
*do,j,1,8
n,j,0.185,j*360/8,-0.6
*enddo
ngen,3,100,1,8,1,0,0,0.3
ngen,4,100,201,208,1,0,0,0.15
ngen,7,100,501,508,1,0,0,0.3
type,2
real,3
mat,3
*do,i,2,6
*do,j,1,7
e,(i-1)*100+j,(i-1)*100+j+1
*enddo
e,(i-1)*100+1,(i-1)*100+8
*enddo
type,2
real,4
mat,3
*do,i,1,5
*do,j,1,7
e,(i+5)*100+j,(i+5)*100+j+1
*enddo
e,(i+5)*100+1,(i+5)*100+8
*enddo
type,2
real,2
mat,2
*do,i,1,11
*do,j,1,8
e,(i-1)*100+j,i*100+j
*enddo
*enddo
allsel,all
nummrg,all
numcmp,all
wpcsys,1,11
cylind,0,0.185,-0.6,0,0,360
cylind,0,0.185,0,0.45,0,360
cylind,0.185,0.3,-0.6,0,0,360
cylind,0,0.185,0.45,2.25,0,360
cylind,0,0.185,2.25,2.55,0,360
cylind,0.185,0.20,2.25,2.55,0,360
cylind,0,0.185,2.55,2.565,0,360
wprota,,90
vsel,s,,,1,7,1
vsbw,all
numcmp,all
wprota,,,90
vsel,s,,,1,14,1
vsbw,all
numcmp,all
vsel,s,,,1,28,1
vglue,all
numcmp,all
wprota,,,-90
wprota,,-90
allsel,all
vsel,s,,,1,16,1
vsel,a,,,21,24,1
vatt,1,1,1
vsel,s,,,17,20,1
vsel,a,,,25,28,1
vatt,2,1,3
allsel,all
lsel,s,,,1,8,1
lsel,a,,,11,22,1
lsel,a,,,25,40,1
lsel,a,,,43,46,1
lesize,all,,,2
lsel,s,,,47,50,1
lsel,a,,,53,56,1
lsel,a,,,58,73,1
lesize,all,,,2
lsel,s,,,98,107,1
lsel,a,,,110,112,2
lesize,all,,,1
lsel,s,,,23,24,1
lsel,a,,,9,10,1
lesize,all,,,2
lsel,s,,,78,82,1
lesize,all,,,3
lsel,s,,,83,87,1
lesize,all,,,6
lsel,s,,,41,42,1
lsel,a,,,88,92,1
lesize,all,,,2
lsel,s,,,93,97,1
lesize,all,,,1
mshkey,1
mshape,0,3d
vsel,s,,,1,28
vmesh,all
allsel,all
nummrg,all
numcmp,all
wprota,,90
csys,0
allsel,all
/solu
csys,11
nsel,s,loc,x,0.3
d,all,all
allsel,all
OUTRES,ALL,2
csys,0
pred,on
cnvtol,f,,0.05,2
autots,1
lnsrch,1
ncnv,2
neqit,50
save
time,1
nsubst,10
asel,s,,,29,32,1
sfa,all,,pres,5468699
allsel,all
acel,,9.8
kbc,1
lswrite,1
time,10
cp,1,ux,298,300,303
d,298,ux,0.015
allsel,all
KBC,0
allsel,all
NSUBST,20,1000000,10
lswrite,2
time,20
d,298,ux,-0.015
allsel,all
KBC,0
allsel,all
NSUBST,100,1000000,10
lswrite,3
time,30
d,298,ux,0.015
allsel,all
KBC,0
allsel,all
NSUBST,100,1000000,10
lswrite,4
time,40
d,298,ux,-0.015
allsel,all
KBC,0
allsel,all
NSUBST,100,1000000,10
lswrite,5
time,50
d,298,ux,0.015
allsel,all
KBC,0
allsel,all
NSUBST,100,1000000,10
lswrite,6
time,60
d,298,ux,-0.015
allsel,all
KBC,0
allsel,all
NSUBST,100,1000000,10
lswrite,7
time,70
d,298,ux,0.015
allsel,all
KBC,0
allsel,all
NSUBST,100,1000000,10
lswrite,8
lssolve,1,8,1
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