网壳结构模型，BEAM4单元，设置的本构关系无法起作用，具体的见下面
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主要问题：用BEAM4建立网壳模型，设置了本构关系（材料非线性），但是运算之后发现单元内力超出345MP，按理说构件已经破坏了，怎么可能还承受更大的力，后来我将本构关系中的极限应力改成很小，发现结构根本就没变，也就是说这个本构关系根本没起作用，好像材料的强度无限大，怎么会这样呢？
程序如下：
finish
/clear
*afun,deg
/filename,suspendome
/title,the model of suspendome
! 设置模型基本参数
*set,kn,6
*set,nx,12
*set,f,17.025
*set,span,92
!定义弦支穹顶结构上部单层网壳的几何参数数组
*dim,numnode,,nx,1
*do,i,1,nx,1
*set,numnode(i),kn*i
*enddo
*dim,num,,nx+1,1
*set,num(1),1
*do,i,2,nx+1,1
*set,num(i),num(i-1)+numnode(i-1)
*enddo
*dim,numcg,,7,1
*set,numcg(1),4.5
*set,numcg(2),4.5
*set,numcg(3),4.5
*set,numcg(4),4.5
*set,numcg(5),5.5
*set,numcg(6),6
*set,numcg(7),6.5
/prep7
!定义单元类型，材料属性，杆件实常数
ET,1,BEAM4
MP,ex,1,2.06e11
MP,dens,1,7850
MP,alpx,1,1.2e-5
MP,prxy,1,0.3
TB,BISO,1,1,2,
TBTEMP,20
TBDATA,,345E6,0,,,,
R,1,37.13E-4,1803.07E-8,1803.07E-8,0.203,0.203
R,2,46.62E-4,2622.04E-8,2622.04E-8,0.219,0.219
R,3,52.34E-4,3709.06E-8,3709.06E-8,0.245,0.245
R,4,66.6E-4,5851.71E-8,5851.71E-8,0.273,0.273
R,5,73.14E-4,7747.42E-8,7747.42E-8,0.299,0.299
R,6,2809E-6,9E-05
R,7,2809E-6,8.97E-04
R,8,2809E-6,7.18E-04
R,9,2809E-6,1.60E-03
R,10,4657E-6,1.54E-03
R,11,4657E-6,2.23E-03
R,12,4657E-6,2.98E-03
R,13,46.62E-4
R,14,5024E-6
!建立上层单层网壳单元
!上弦节点坐标
CSYS,2
r=(span*span/4+f*f)/(2*f)
*set,dpha,Atn(span/2/sqrt(r*r-span*span/4))/nx
N,1,r,0,90
*do,i,1,nx
*do,j,1,kn*i
x=r
y=(j-1)*360/(kn*i)
z=90-i*dpha
N,1+kn*(i-1)*i/2+j,x,y,z
*enddo
*enddo
local,11,1,0,0,0
csys,11
!上部单层网壳杆件
TYPE,1
MAT,1
REAL,1
!环向杆
*do,i,1,nx
*do,j,1,kn*i-1
E,1+kn*(i-1)*i/2+j,1+kn*(i-1)*i/2+j+1
*enddo
E,1+kn*(i-1)*i/2+1,1+kn*(i-1)*i/2+kn*i
*enddo
!径向单元
*do,i,1,kn
E,1,1+i
*enddo
*do,j,1,nx-1
*do,k,1,kn
*do,i,1,j+1
*IF,i,EQ,j+1,THEN
*IF,k,EQ,kn,THEN
E,1+kn*(j-1)*j/2+1,1+kn*(j+1)*j/2+(k-1)*(j+1)+i !第一个节点和最后一个节点的连杆
*ELSE
E,1+kn*(j-1)*j/2+(k-1)*j+i,1+kn*(j+1)*j/2+(k-1)*(j+1)+i !一般区内的最后一根连杆
*ENDIF
*ELSE
E,1+kn*(j-1)*j/2+(k-1)*j+i,1+kn*(j+1)*j/2+(k-1)*(j+1)+i !一般正向连杆
*ENDIF
*ENDDO
*DO,i,1,j
E,1+kn*(j-1)*j/2+(k-1)*j+i,1+kn*(j+1)*j/2+(k-1)*(j+1)+i+1 !一般负向连杆
*ENDDO
*ENDDO
*ENDDO
!根据图纸修改单层网壳截面特性
*DIM,area,,32
*set,area(1),2,2,2,2,2,3,2,3 !
*set,area(9),4,5,2,5,2,5,2,5 ! 环向杆钢管规格
*set,area(17),2,1,1,1,1,1,1,1 !
*set,area(25),1,1,1,1,1,1,2,2 ! 径向杆钢管规格
!修改环向杆截面特性
num_elem_b=1 !第一圈环向杆起始编号
num_elem_e=6 ! 末尾编号
*do,i,1,nx,1
ESEL,S,,,num_elem_b,num_elem_e,1
EMODIF,all,real,area(i)
ESEL,all
num_elem_b=num_elem_b+i*kn
num_elem_e=num_elem_e+(i+1)*kn
*enddo
sum_num=nx*kn+nx*(nx-1)/2*kn
!修改径向杆截面特性
num_elem_b=sum_num+1
num_elem_e=sum_num+6
*do,i,1,nx,1
ESEL,s,,,num_elem_b,num_elem_e,1
EMODIF,all,real,area(i+16)
ESEL,all
num_elem_b=num_elem_b+6+12*(i-1)
num_elem_e=num_elem_e+6+12*i
*enddo
!压缩编号
NUMCMP,node
NUMCMP,elem
!建立约束
CSYS,11
NROTAT,398,466,4
*DO,i,1,18
D,394+4*i,uz,0
D,394+4*i,uy,0
D,394+4*i,ux,0
*enddo
!建立表面效应单元
local,11,0,0,0,0
ET,10,SURF154,,1,,1
R,10,,,,,,,0.1,0.1,0.1
MP,DENS,10,0
TYPE,10
MAT,10
REAL,10
esys,11
ENUMmax1=ELMIQR(0,14)+1
*do,j,1,kn-1
E,1,j+1,j+2
*enddo
E,1,kn+1,2
*do,i,1,nx-1
*do,j,1,kn
*do,k,1,i+1
*if,k,EQ,i+1,then
*if,j,EQ,kn,then
E,1+kn*(i-1)*i/2+1,1+kn*(i+1)*i/2+(j-1)*(i+1)+k,1+kn*(i+1)*i/2+1
*ELSE
E,1+kn*(i-1)*i/2+(j-1)*i+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k+1
*endif
*else
E,1+kn*(i-1)*i/2+(j-1)*i+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k+1
*endif
*enddo
*do,k,1,i
*if,k,EQ,i,then
*if,j,EQ,kn,then
E,1+kn*(i-1)*i/2+(j-1)*i+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k+1,1+kn*(i-1)*i/2+1
*else
E,1+kn*(i-1)*i/2+(j-1)*i+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k+1,1+kn*(i-1)*i/2+(j-1)*i+k+1
*endif
*else
E,1+kn*(i-1)*i/2+(j-1)*i+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k+1,1+kn*(i-1)*i/2+(j-1)*i+k+1
*endif
*enddo
*enddo
*enddo
ENUMmax2=ELMIQR(0,14)
/SOLU
ANTYPE,0
NLGEOM,ON
SSTIF,ON
AUTOTS,ON
NROPT,full
FCUM,add
!ACEL,0,0,-9.8
TREF,20
TUNIF,20
!加载
P=-500 !第一荷载步
*do,i,ENUMmax1,ENUMmax2,1 !去掉显示面单元 ALLSEL ESEL,U,MAT,,10
SFE,i,3,pres,,P
*enddo
TIME,5
KBC,0
NSUBST,10
ALLSEL,ALL
LSWRITE,1，
P=-1000 !第二荷载步
*do,i,ENUMmax1,ENUMmax2,1 !去掉显示面单元 ALLSEL ESEL,U,MAT,,10
SFE,i,3,pres,,P
*enddo
TIME,10
KBC,0
NSUBST,10
ALLSEL,ALL
LSWRITE,2，
P=-2000 !第三荷载步
*do,i,ENUMmax1,ENUMmax2,1 !去掉显示面单元 ALLSEL ESEL,U,MAT,,10
SFE,i,3,pres,,P
*enddo
TIME,15
KBC,0
NSUBST,10
ALLSEL,ALL
LSWRITE,3，
P=-4000 !第四荷载步
*do,i,ENUMmax1,ENUMmax2,1 !去掉显示面单元 ALLSEL ESEL,U,MAT,,10
SFE,i,3,pres,,P
*enddo
TIME,20
KBC,0
NSUBST,10
ALLSEL,ALL
LSWRITE,4，
OUTPR,ALL,ALL
LSSOLVE,1,4,1
FINISH
/post1
ETABLE,SX,LS,1
PLLS,SX,SX
ESEL,s,TYPE,,1
程序如下：
finish
/clear
*afun,deg
/filename,suspendome
/title,the model of suspendome
! 设置模型基本参数
*set,kn,6
*set,nx,12
*set,f,17.025
*set,span,92
!定义弦支穹顶结构上部单层网壳的几何参数数组
*dim,numnode,,nx,1
*do,i,1,nx,1
*set,numnode(i),kn*i
*enddo
*dim,num,,nx+1,1
*set,num(1),1
*do,i,2,nx+1,1
*set,num(i),num(i-1)+numnode(i-1)
*enddo
*dim,numcg,,7,1
*set,numcg(1),4.5
*set,numcg(2),4.5
*set,numcg(3),4.5
*set,numcg(4),4.5
*set,numcg(5),5.5
*set,numcg(6),6
*set,numcg(7),6.5
/prep7
!定义单元类型，材料属性，杆件实常数
ET,1,BEAM4
MP,ex,1,2.06e11
MP,dens,1,7850
MP,alpx,1,1.2e-5
MP,prxy,1,0.3
TB,BISO,1,1,2,
TBTEMP,20
TBDATA,,345E6,0,,,,
R,1,37.13E-4,1803.07E-8,1803.07E-8,0.203,0.203
R,2,46.62E-4,2622.04E-8,2622.04E-8,0.219,0.219
R,3,52.34E-4,3709.06E-8,3709.06E-8,0.245,0.245
R,4,66.6E-4,5851.71E-8,5851.71E-8,0.273,0.273
R,5,73.14E-4,7747.42E-8,7747.42E-8,0.299,0.299
R,6,2809E-6,9E-05
R,7,2809E-6,8.97E-04
R,8,2809E-6,7.18E-04
R,9,2809E-6,1.60E-03
R,10,4657E-6,1.54E-03
R,11,4657E-6,2.23E-03
R,12,4657E-6,2.98E-03
R,13,46.62E-4
R,14,5024E-6
!建立上层单层网壳单元
!上弦节点坐标
CSYS,2
r=(span*span/4+f*f)/(2*f)
*set,dpha,Atn(span/2/sqrt(r*r-span*span/4))/nx
N,1,r,0,90
*do,i,1,nx
*do,j,1,kn*i
x=r
y=(j-1)*360/(kn*i)
z=90-i*dpha
N,1+kn*(i-1)*i/2+j,x,y,z
*enddo
*enddo
local,11,1,0,0,0
csys,11
!上部单层网壳杆件
TYPE,1
MAT,1
REAL,1
!环向杆
*do,i,1,nx
*do,j,1,kn*i-1
E,1+kn*(i-1)*i/2+j,1+kn*(i-1)*i/2+j+1
*enddo
E,1+kn*(i-1)*i/2+1,1+kn*(i-1)*i/2+kn*i
*enddo
!径向单元
*do,i,1,kn
E,1,1+i
*enddo
*do,j,1,nx-1
*do,k,1,kn
*do,i,1,j+1
*IF,i,EQ,j+1,THEN
*IF,k,EQ,kn,THEN
E,1+kn*(j-1)*j/2+1,1+kn*(j+1)*j/2+(k-1)*(j+1)+i !第一个节点和最后一个节点的连杆
*ELSE
E,1+kn*(j-1)*j/2+(k-1)*j+i,1+kn*(j+1)*j/2+(k-1)*(j+1)+i !一般区内的最后一根连杆
*ENDIF
*ELSE
E,1+kn*(j-1)*j/2+(k-1)*j+i,1+kn*(j+1)*j/2+(k-1)*(j+1)+i !一般正向连杆
*ENDIF
*ENDDO
*DO,i,1,j
E,1+kn*(j-1)*j/2+(k-1)*j+i,1+kn*(j+1)*j/2+(k-1)*(j+1)+i+1 !一般负向连杆
*ENDDO
*ENDDO
*ENDDO
!根据图纸修改单层网壳截面特性
*DIM,area,,32
*set,area(1),2,2,2,2,2,3,2,3 !
*set,area(9),4,5,2,5,2,5,2,5 ! 环向杆钢管规格
*set,area(17),2,1,1,1,1,1,1,1 !
*set,area(25),1,1,1,1,1,1,2,2 ! 径向杆钢管规格
!修改环向杆截面特性
num_elem_b=1 !第一圈环向杆起始编号
num_elem_e=6 ! 末尾编号
*do,i,1,nx,1
ESEL,S,,,num_elem_b,num_elem_e,1
EMODIF,all,real,area(i)
ESEL,all
num_elem_b=num_elem_b+i*kn
num_elem_e=num_elem_e+(i+1)*kn
*enddo
sum_num=nx*kn+nx*(nx-1)/2*kn
!修改径向杆截面特性
num_elem_b=sum_num+1
num_elem_e=sum_num+6
*do,i,1,nx,1
ESEL,s,,,num_elem_b,num_elem_e,1
EMODIF,all,real,area(i+16)
ESEL,all
num_elem_b=num_elem_b+6+12*(i-1)
num_elem_e=num_elem_e+6+12*i
*enddo
!压缩编号
NUMCMP,node
NUMCMP,elem
!建立约束
CSYS,11
NROTAT,398,466,4
*DO,i,1,18
D,394+4*i,uz,0
D,394+4*i,uy,0
D,394+4*i,ux,0
*enddo
!建立表面效应单元
local,11,0,0,0,0
ET,10,SURF154,,1,,1
R,10,,,,,,,0.1,0.1,0.1
MP,DENS,10,0
TYPE,10
MAT,10
REAL,10
esys,11
ENUMmax1=ELMIQR(0,14)+1
*do,j,1,kn-1
E,1,j+1,j+2
*enddo
E,1,kn+1,2
*do,i,1,nx-1
*do,j,1,kn
*do,k,1,i+1
*if,k,EQ,i+1,then
*if,j,EQ,kn,then
E,1+kn*(i-1)*i/2+1,1+kn*(i+1)*i/2+(j-1)*(i+1)+k,1+kn*(i+1)*i/2+1
*ELSE
E,1+kn*(i-1)*i/2+(j-1)*i+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k+1
*endif
*else
E,1+kn*(i-1)*i/2+(j-1)*i+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k+1
*endif
*enddo
*do,k,1,i
*if,k,EQ,i,then
*if,j,EQ,kn,then
E,1+kn*(i-1)*i/2+(j-1)*i+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k+1,1+kn*(i-1)*i/2+1
*else
E,1+kn*(i-1)*i/2+(j-1)*i+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k+1,1+kn*(i-1)*i/2+(j-1)*i+k+1
*endif
*else
E,1+kn*(i-1)*i/2+(j-1)*i+k,1+kn*(i+1)*i/2+(j-1)*(i+1)+k+1,1+kn*(i-1)*i/2+(j-1)*i+k+1
*endif
*enddo
*enddo
*enddo
ENUMmax2=ELMIQR(0,14)
/SOLU
ANTYPE,0
NLGEOM,ON
SSTIF,ON
AUTOTS,ON
NROPT,full
FCUM,add
!ACEL,0,0,-9.8
TREF,20
TUNIF,20
!加载
P=-500 !第一荷载步
*do,i,ENUMmax1,ENUMmax2,1 !去掉显示面单元 ALLSEL ESEL,U,MAT,,10
SFE,i,3,pres,,P
*enddo
TIME,5
KBC,0
NSUBST,10
ALLSEL,ALL
LSWRITE,1，
P=-1000 !第二荷载步
*do,i,ENUMmax1,ENUMmax2,1 !去掉显示面单元 ALLSEL ESEL,U,MAT,,10
SFE,i,3,pres,,P
*enddo
TIME,10
KBC,0
NSUBST,10
ALLSEL,ALL
LSWRITE,2，
P=-2000 !第三荷载步
*do,i,ENUMmax1,ENUMmax2,1 !去掉显示面单元 ALLSEL ESEL,U,MAT,,10
SFE,i,3,pres,,P
*enddo
TIME,15
KBC,0
NSUBST,10
ALLSEL,ALL
LSWRITE,3，
P=-4000 !第四荷载步
*do,i,ENUMmax1,ENUMmax2,1 !去掉显示面单元 ALLSEL ESEL,U,MAT,,10
SFE,i,3,pres,,P
*enddo
TIME,20
KBC,0
NSUBST,10
ALLSEL,ALL
LSWRITE,4，
OUTPR,ALL,ALL
LSSOLVE,1,4,1
FINISH
/post1
ETABLE,SX,LS,1
PLLS,SX,SX
ESEL,s,TYPE,,1
