General Mechanical

General Mechanical

Modal analysis error

    • dardhruv
      Subscriber

      Hi,


      I am doing Modal acoustic analysis, and I got this warning:


       


      *** WARNING ***                         CP =       0.969   TIME= 14:53:20


      Element shape checking is currently inactive.  Issue SHPP,ON or  SHPP,WARN to reactivate, if desired.                                    


       


      *** WARNING ***                         CP =       1.281   TIME= 14:53:21


      The ending frequency 100000000 (Hz) in MODOPT command may be too high   


      for acoustic modal analysis.  It is recommended to use 1000000 (Hz) as  


      the ending frequency.                                                   


       


      *** WARNING ***                         CP =       2.172   TIME= 14:53:22


      Coefficient ratio exceeds 1.0e8 - Check results.                        


       


      *** WARNING ***                         CP =       2.391   TIME= 14:53:22


      The damped eigensolver did not find a damping matrix.  For efficiency,  


      please use an eigensolver that does not consider damping to solve this  


      model.                                                                  


       


      *** WARNING ***                         CP =       3.844   TIME= 14:53:23


      The eigenproblem is ill-conditioned (relative residual from test linear 


      solve: 1.137193E-03).  The accuracy of the solution may not be          


      satisfactory.  Modifying the initial value of the frequency shift       


      (FREQB in the MODOPT command) or changing the boundary conditions of    


      the model might solve the problem.                                      


       


      *** WARNING ***                         CP =      31.172   TIME= 14:53:51


      Fewer modes than the requested number of modes ( 12 ) were computed.    


      The range specified (FREQB= 0, FREQE= 100000000) contains only 0        


      modes.                                                                  


       


       

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