屈曲分析后无模态，各位大侠帮忙看看是什么原因？？？

21105309

用solid46单元，材料定义如下：
/prep7

ET , 1 , solid46
keyopt,1,5,2
KEYOPT,1,8,1
KEYOPT,1,2,0
MPTEMP,,,,,,,,  
MPTEMP,1,0  
MPDATA,EX,1,,0.5E+10     
MPDATA,EY,1,,3.3E+10
MPDATA,EZ,1,,0.5E+10
MPDATA,PRXY,1,,0.3
MPDATA,PRYZ,1,,0.2
MPDATA,PRXZ,1,,0.2
MPDATA,GXY,1,,0.6E+10                       
MPDATA,GYZ,1,,0.6E+10                        
MPDATA,GXZ,1,,0.6E+10                        
R,1
RMODIF,1,1,13,0,0,0,0,0
RMODIF,1,13,1,0,0.001,1,0,0.001,
RMODIF,1,19,1,0,0.001, 1,0,0.001
RMODIF,1,25,1,0,0.001,1,0,0.001
RMODIF,1,31,1,0,0.001,
r,3
RMODIF,3,1,13,0,0,0,0,0
RMODIF,3,13,1,0,0.001,1,0,0.001,
RMODIF,3,19,1,0,0.001, 1,0,0.001
RMODIF,3,25,1,0,0.001,1,0,0.001
RMODIF,3,31,1,0,0.001,
..........
..........
.........


/solu
allsel
nsel,s,loc,z,0.05
nsel,r,loc,y,0.005-bottom
d,all,ux
d,all,uy
d,all,uz
nsel,s,loc,z,1.95
nsel,r,loc,y,0.005-bottom
d,all,uy

allsel
*do,i,1,14
nsel,s,loc,y,0.189+top1
nsel,r,loc,z,0.7,1.3
nsel,r,loc,x,q(i,1)/1000
f,all,fy,-q(15-i,2)*1000
*enddo
allsel
solve
finish

!!!!!!!!特征值屈曲分析
/solu
antype,1
bucopt,lanb,1,0
mxpand,1
solve
finish

静力分析没错，进行屈曲分析之后提示：
*** WARNING ***                         CP =     570.078   TIME= 13:43:41
Repeated Lanczos shift and factorize steps did not yield additional     
eigenvalues in the requested frequency range.  Either the eigenvalues   
are widely separated or, there are only 0 eigenvalues in the frequency  
range specified (FREQB and FREQE in MODOPT command).                    
*** WARNING ***                         CP =     570.125   TIME= 13:43:41
There are no modes in the specified range.

后又将模态扩展改为：
mxpand，1,0,10000,0,0.01

还是没用，请教各位大侠，这是什么原因？？？