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Participative mass for modal analysis unit and kene — Ansys Learning Forum

Participative mass for modal analysis unit and kene

eric56eric56 Member Posts: 3

Hello every body

I have few question for modale analysis.

please, What is the unit for effective mass for rotx direction ?

         ***** PARTICIPATION FACTOR CALCULATION ***** X DIRECTION

                                                                                 CUMULATIVE    RATIO EFF.MASS

 MODE  FREQUENCY      PERIOD     PARTIC.FACTOR    RATIO   EFFECTIVE MASS  MASS FRACTION  TO TOTAL MASS

    1    20.5824      0.48585E-01   0.0000       0.000000    0.00000        0.00000        0.00000   

    2    128.966      0.77540E-02   0.0000       0.000000    0.00000        0.00000        0.00000   

  SU    Hz            second      Without Unit    WU        Tonne=1000 Kg      WU               WU


         ***** PARTICIPATION FACTOR CALCULATION *****ROTX DIRECTION

                                                                                 CUMULATIVE    RATIO EFF.MASS

 MODE  FREQUENCY      PERIOD     PARTIC.FACTOR    RATIO   EFFECTIVE MASS  MASS FRACTION  TO TOTAL MASS

    1    20.5824      0.48585E-01  0.17448E-01   1.000000   0.304446E-03   0.969786       0.969548   

    2    128.966      0.77540E-02 -0.28291E-02   0.162140   0.800366E-05   0.995281       0.254887E-01

   SU    Hz            second      Without Unit    WU        ????           WU               WU


      ***** MODAL MASSES, KINETIC ENERGIES, AND TRANSLATIONAL EFFECTIVE MASSES SUMMARY *****


                                                                        EFFECTIVE MASS

 MODE FREQUENCY  MODAL MASS    KENE     |     X-DIR     RATIO%  Y-DIR     RATIO%  Z-DIR     RATIO%

    1  20.58     0.5860E-02  49.00      |    0.000       0.00 0.2206E-15   0.00 0.1437E-01  61.03

    2  129.0     0.5861E-02  1924.      |    0.000       0.00 0.5714E-15   0.00 0.4420E-02  18.77

  SU    Hz         ????       ????         Tonne=1000 Kg   WU  Tonne=1000 Kg WU  Tonne=1000 Kg  WU

Please what is kene and his unit ?

thanK you

Answers

  • 1shan1shan Ansys Employee Posts: 262

    Hello @eric56,

    The kinetic energy is 1/2*modal mass*freq^2 and regrading effective mass for rotational degree, I am not entirely sure but my guess is it is effective mass multiplied by distance from centroidal axis.


    Regards,

    Ishan.

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