求助！ansys中做屈曲分析时用自带截面和自定义截面为什么结果相差很多？新手请多多指教！

附命令流：
命令流1
file_name='1'
Height=0.15
broad=0.15
flange_thick=0.01
web_thick=0.006
Web_Partitions=20
Column_Length=4
Col_ele_num=100
fy=215e6
fu=275e6
elastic_modulus=2.06e11
density=7850
poisson_ratio=0.3
eu=0.076
col_axial_force=1
load_control_factor=0.8
ini_geo_imp_factor=0.001
/PREP7
k, 1,-broad/2 , Height/2
k, 2, broad/2 , Height/2
k, 3, broad/2 , Height/2-flange_thick
k, 4, web_thick/2 , Height/2-flange_thick
k, 5, web_thick/2 , -Height/2+flange_thick
k, 6, broad/2 , -Height/2+flange_thick
k, 7, broad/2 , -Height/2
k,8, -broad/2 , -Height/2
k,9, -broad/2 , -Height/2+flange_thick
k,10,-web_thick/2 , -Height/2+flange_thick
k,11,-web_thick/2 , Height/2-flange_thick
k,12,-broad/2 , Height/2-flange_thick
L,1,2
L,2,3
L,3,4
L,4,5
L,5,6
L,6,7
L,7,8
L,8,9
L,9,10
L,10,11
L,11,12
L,12,1
LSEL,ALL
AL,ALL
nummrg,all
ET,1,PLANE82
ALLSEL,ALL
AATT,1,,1, !为准备划分的面定义特性
MSHAPE,0,2D ！指定单元形状
MSHKEY,0 ! 指定网格划分方式
!SMRTSIZE,6
AMESH,ALL
nummrg,all
ALLSEL
secwrite,Beam_Section,sect,,1
finish
/CLEAR,NOSTART
/PREP7
Height=0.15
broad=0.15
flange_thick=0.01
web_thick=0.006
Web_Partitions=20
Column_Length=4
Col_ele_num=100
fy=215e6
fu=275e6
elastic_modulus=2.06e11
density=7850
poisson_ratio=0.3
eu=0.076
col_axial_force=10
load_control_factor=0.8
ini_geo_imp_factor=0.001
ET,1,BEAM188
KEYOPT,1,8,3
SECTYPE,1,BEAM,MESH,
SECOFFSET,CENT,,,
SECREAD,'Beam_Section','sect',' ',MESH
MPTEMP,1,0
MPDATA,EX,1,,elastic_modulus
MPDATA,DENS,1,,density
MPDATA,PRXY,1,,poisson_ratio
TB,MKIN,1,,,0
TBMODIF,1,2,fy/elastic_modulus
TBMODIF,1,3,eu
TBMODIF,2,2,fy
TBMODIF,2,3,fu
N,1
N,Col_ele_num+1,,Column_Length
Fill
N,Col_ele_num+2,Column_Length/2,Column_Length/2,
*do,i,1,Col_ele_num
e,i,i+1,Col_ele_num+2
*enddo
ALLSEL,ALL
/ESHAPE,1.0
eplot
/SOLU
D,1,UX,,,,,UY,UZ,ROTY
D,Col_ele_num+1,UX,,,,,UZ,ROTY
F,Col_ele_num+1,FY,-(col_axial_force)
ANTYPE,STATIC
PSTRES,ON
SOLVE
save
FINISH
/SOLU
ANTYPE,BUCKLE
BUCOPT,SUBSP,1
MXPAND,,,,yes
OUTPR,nsol,all
SOLVE
save
FINISH
/POST1
SET,FIRST
NSORT,U,Z
*GET,Z_disp_01,SORT,,MAX
*GET,Z_disp_02,SORT,,MIN
Z_disp_02=ABS(Z_disp_02)
*IF,Z_disp_01,LT,Z_disp_02,THEN
Z_disp_01=Z_disp_02
*ENDIF
*GET,load_factor,MODE,1,FREQ
col_axial_force=col_axial_force*load_factor*load_control_factor
命令流2
FILE_NAME='1'
HEIGHT=0.15
WEB_THICK=0.006
BROAD=0.15
FLANGE_THICK=0.01
LENGTH=4
ELE_NUM=100
FY=215E6
FU=275E6
EU=0.076
ELASTIC_MODULUS=2.06E11
DENSITY=7850
POISSON_RATIO=0.3
AXIAL_FORCE=1
LOAD_CONTROL_FACTOR=0.8
INI_IMP_FACTOR=0.001
/PREP7
ET,1,BEAM188
MPTEMP,1,0
MPDATA,EX,1,,ELASTIC_MODULUS
MPDATA,DENS,1,,DENSITY
MPDATA,PRXY,1,,POISSON_RATIO
TB,MKIN,1,,,0
TBMODIF,1,2,FY/ELASTIC_MODULUS
TBMODIF,1,3,EU
TBMODIF,2,2,FY
TBMODIF,2,3,FU
SECTYPE,1,BEAM,I,,0
SECDATA,BROAD,BROAD,HEIGHT,FLANGE_THICK,FLANGE_THICK,WEB_THICK,0,0,0,0
N,1
N,ELE_NUM+1,,LENGTH
FILL
N,ELE_NUM+2,LENGTH/2,LENGTH/2
*DO,I,1,ELE_NUM
E,I,I+1,ELE_NUM+2
*ENDDO
ALLSEL,ALL
/ESHAPE,1.0
EPLOT
/SOLU
D,1,UX,,,,,UY,UZ,ROTY
D,ELE_NUM+1,UX,,,,,UZ,ROTY
F,ELE_NUM,FY,-(AXIAL_FORCE)
ANTYPE,STATIC
PSTRES,ON
SOLVE
SAVE
FINISH
/SOLU
ANTYPE,BUCKLE
BUCOPT,SUBSP,1
MXPAND,,,,YES
OUTPR,NSOL,ALL
SOLVE
SAVE
FINISH
/POST1
SET,FIRST
NSORT,U,Z
*GET,Z_DISP_01,SORT,,MAX
*GET,Z_DISP_02,SORT,,MIN
Z_DISP_02=ABS(Z_DISP_02)
*IF,Z_DISP_01,LT,Z_DISP_02,THEN
Z_DISP_01=Z_DISP_02
*ENDIF
*GET,LOAD_FACTOR,MODE,1,FREQ
AXIAL_FORCE=AXIAL_FORCE*LOAD_FACTOR*LOAD_CONTROL_FACTOR
帮忙看一下，谢谢！