General Mechanical

General Mechanical

reduce modal basis

    • sara_hamouni

      Hello everyone

      I am trying to reduce a modal base of 1200 modes using the participation factor but I don't know how to choose the significant value. Is there a method to determine this value on ANSYS APDL?


      antype, MODAL, RESTART

      mxpand,,,, yes,1e-5,, EFFM                    ! Mode selection is based on the participation factor,

      modseloption, yes,no,yes, no,no,no     ! Only direction X and Z is selected,



      Here I put 1e-5 as an example

      thanks in advance

    • 1shan
      Ansys Employee
      If the ModSelMethod =EFFM, the significance level of a mode is defined as the modal effective mass, divided by the total mass. Any mode whose significance level is less than this value is considered insignificant and is not expanded. The higher thesignificancethreshold, the fewer the number of modes expanded.The significance value defaults to 0.001 (which should work in most cases) , except for the case of DDAM mode selection method where it defaults to 0.01. Do check out this useful link
      " target="blank">
      which gives some insight on how to choose the number of modes using participation factor and effective mass.
      Regards Ishan.

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