这个warning谁知道是什么原因造成的？

zhangyuli

*** USER WARNING MESSAGE 6644 (FRPROD)
    SOME OR ALL COMPUTED EXCITATION FREQUENCIES ARE OUTSIDE THE RANGE F1 AND F2 FOR FREQ4 BULK DATA ENTRY WITH ID =1
     THESE COMPUTED EXCITATION FREQUENCIES ARE IGNORED.
1    MSC.NASTRAN JOB CREATED ON 27-MAR-13 AT 21:18:20                         MARCH  28, 2013  MD NASTRAN   4/27/11   PAGE  7653
     RANDOM                                                                                                                        
0                                                                                                            SUBCASE 1              

*** USER WARNING MESSAGE 7697 (GKAM1A)
     ONE OR MORE MODAL DAMPING VALUES FOR STRUCTURE MODES ARE EITHER NEGATIVE OR HAVE RESULTED FROM EXTRAPOLATION OF THE
     TABDMP1 1 TABLE DATA AS SHOWN BELOW:

     CYCLIC FREQUENCY =  4.565918E+02  MODAL DAMPING VALUE =  3.000000E-02  (BY EXTRAPOLATION BEYOND THE RIGHT END OF THE TABLE)
     CYCLIC FREQUENCY =  7.479011E+02  MODAL DAMPING VALUE =  3.000000E-02  (BY EXTRAPOLATION BEYOND THE RIGHT END OF THE TABLE)
     CYCLIC FREQUENCY =  8.596663E+02  MODAL DAMPING VALUE =  3.000000E-02  (BY EXTRAPOLATION BEYOND THE RIGHT END OF THE TABLE)
     CYCLIC FREQUENCY =  1.277522E+03  MODAL DAMPING VALUE =  3.000000E-02  (BY EXTRAPOLATION BEYOND THE RIGHT END OF THE TABLE)
     CYCLIC FREQUENCY =  2.266442E+03  MODAL DAMPING VALUE =  3.000000E-02  (BY EXTRAPOLATION BEYOND THE RIGHT END OF THE TABLE)
     CYCLIC FREQUENCY =  2.464301E+03  MODAL DAMPING VALUE =  3.000000E-02  (BY EXTRAPOLATION BEYOND THE RIGHT END OF THE TABLE)

supermenxp

在做模态计算时，你设置了模态的频率范围，把这个范围扩大一下试试看。