Structural Dynamics

Structural Dynamics

In a random vibration analysis, what is “GRMS” and how can it be calculated?

    • FAQFAQ
      Participant

      In an ANSYS random vibration analysis, root-mean-square (RMS) values are referred to as “one-sigma” values. So, the RMS acceleration is the one-sigma acceleration. “G” refers to the acceleration expressed in terms of the gravitational acceleration. So “GRMS” is the one-sigma acceleration in terms of G. In /POST1, the calculated one-sigma accelerations are stored in load step 5. To obtain the one-sigma acceleration in terms of G (GRMS), simply divide the one-sigma acceleration values by the gravitational acceleration constant using the SET command. /post1 set,5,1,1/386.4 ! for BIN unit system