Looking to automate export velocity FRF via input file running in a cluster Ansys harmonic analysis

SK
SK Member Posts: 21
10 Comments First Anniversary Name Dropper
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in Structures

Hello Experts,

I need to export velocity FRF of predefined named selections in a harmonic analysis. I'm creating a input file from GUI and solving it using an inhouse HPC cluster. RST file size is very large that I cant download it to generate a FRF. So need a method by which it will create a CSV/txt file for required frequency response plot then I can download only that file.

Answers

  • Mac2001
    Mac2001 Member Posts: 5
    First Comment
    **

    Hi,

    You can add some code to the end of the input file. Something like:
    FRF_point = 55247 !! look at what node you use !!
    P_point = 7541
    P_point2 = 7545
    file_namex = 'Dx_ow'
    file_namey = 'Dy_ow'
    file_namez = 'Dz_ow'

    /post26
    NSOL,2,FRF_point,u,x,,x_disp !save displacement to var2,var3,var4
    NSOL,3,FRF_point,u,y,,y_disp
    NSOL,4,FRF_point,u,z,,z_disp

    *DIM,freq_1,ARRAY,My_Fstep ! Dimension for frequency results
    *DIM,x_disp_r,ARRAY,My_Fstep ! Dimension for x displacement
    *DIM,x_disp_i,ARRAY,My_Fstep
    *DIM,y_disp_r,ARRAY,My_Fstep
    *DIM,y_disp_i,ARRAY,My_Fstep
    *DIM,z_disp_r,ARRAY,My_Fstep
    *DIM,z_disp_i,ARRAY,My_Fstep

    VGET,freq_1,1,,0 ! Store freq data of variable 1 into freq_p1
    VGET,x_disp_r,2,,0 ! Store freq data of variable 2 into x_disp_r
    VGET,x_disp_i,2,,1 ! Store freq data of variable 2 into x_disp_i
    VGET,y_disp_r,3,,0
    VGET,y_disp_i,3,,1
    VGET,z_disp_r,4,,0
    VGET,z_disp_i,4,,1

    /com, The pres_r = %pres_r%
    /com, The pres_i = %pres_i%
    /com, The pres2_r = %pres2_r%
    /com, The y_disp_r = %y_disp_r%
    /com, The z_disp_i = %z_disp_i%

    *CFOPEN, file_namex, csv
    *VWRITE,freq_1(1),x_disp_r(1),x_disp_i(1) ! Write array in given format
    (6x,F12.6,',',6x,E12.6,',',6x,E12.6)
    *CFCLOSE ! Close file

    *CFOPEN, file_namey, csv
    *VWRITE,freq_1(1),y_disp_r(1),y_disp_i(1)
    (6x,F12.6,',',6x,E12.6,',',6x,E12.6)
    *CFCLOSE

    *CFOPEN, file_namez, csv
    *VWRITE,freq_1(1),z_disp_r(1),z_disp_i(1)
    (6x,F12.6,',',6x,E12.6,',',6x,E12.6)
    *CFCLOSE

    Then you need to do something with the displacement to get the velocity because it does not save that.
    Kind regards,

    Michael

  • SK
    SK Member Posts: 21
    10 Comments First Anniversary Name Dropper
    **

    Hi @Mac2001
    Thanks for sharing this.
    I tried running it, it does creates the CSV files but only one row of data.
    May I know how to create data along the freq range such that once I open the CSV file I can plot the FRF.
    Thanks.

  • Mac2001
    Mac2001 Member Posts: 5
    First Comment
    **

    Ah you should define My_Fstep as the number of freq points.

  • SK
    SK Member Posts: 21
    10 Comments First Anniversary Name Dropper
    **

    Ok thanks, I'm able to generate this FRF.
    One question, if you further help me please, lets say this one I can postprocess offline to get the disp amplitudes and then calculate the velocity and acceleration.
    How can I do the this same 'disp amplitudes and then calculate the velocity and acceleration' in script it self?

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