{"id":287005,"date":"2023-06-04T09:04:41","date_gmt":"2023-06-04T09:04:41","guid":{"rendered":"\/forum\/forums\/topic\/how-to-carry-out-harmonic-analysis-using-apdl-commands-under-modal-analysis\/"},"modified":"2023-06-04T09:04:41","modified_gmt":"2023-06-04T09:04:41","slug":"how-to-carry-out-harmonic-analysis-using-apdl-commands-under-modal-analysis","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-carry-out-harmonic-analysis-using-apdl-commands-under-modal-analysis\/","title":{"rendered":"How to carry out harmonic analysis using APDL commands under modal analysis"},"content":{"rendered":"

HI everyone,<\/p>\n

I am doing a MOGA optimization where some information from modal analysis is required in harmonic analysis, and hence the objective parameter ( energy) is maximized (which is obtained from harmonic analysis). To enforce the optimizer tool to go through the modal analysis first, then the harmonic analysis, I had to Preserve Design Points After DX Run and Retain Data for Each Preserved Design Point, otherwise each new design point will  run only the harmonic analysis based on the old data from the modal analysis (not updated) to avoid what is shown in pic1.<\/p>\n

1<\/span>\"\". <\/span><\/p>\n

This resulted in a huge amount of data. How do I reduce this data knowing that I set the optimization properties (as said previously) to Preserve Design Points After DX Run and Retain Data for Each Preserved Design Point ?<\/p>\n

I tried to write the next code in the solution block  of Modal analysis as shown in pic 2.<\/p>\n

 <\/span>\"\"<\/p>\n

in order to avoid using harmonic analysis and hence enfoce the optimizer to update the Modal analysis and choose no to Preserve Design Points After DX Run , so the preserved data volume is reduced :<\/p>\n

*GET,Fd,MODE,2,FREQ  !extract the needed information from modal analysis<\/div>\n
*SET,x1,Fd-0.01 ! set target harmonic analysis frequency range<\/div>\n
*SET,x2,Fd+0.01<\/div>\n
\/PREP7<\/div>\n
ESEL,S,ENAME,,185<\/div>\n
D,ALL,UZ,10    ! set the loads for harmonic analysis<\/div>\n
ALLSEL<\/div>\n
HROPT,FULL   !start harmonic analysis<\/div>\n
HROUT,ON<\/div>\n
LUMPM,0<\/div>\n
EQSLV, ,0,<\/div>\n
PSTRES,0<\/div>\n
HARFRQ,x1,x2<\/div>\n
NSUBST,20<\/div>\n
KBC,1<\/div>\n
*DIM,energy_array,ARRAY,20<\/div>\n
\/POST1<\/div>\n
i=1<\/div>\n
my_energy = 0<\/div>\n
*DO, step, 1,39, 2 <\/div>\n
   set,,,,,,,step         ! store results for set step<\/div>\n
   ESEL,S,ENAME,,185<\/div>\n
   etable,energy,sene<\/div>\n
   ssum<\/div>\n
   <\/div>\n
   *get,ST_energy,ssum,,ITEM,energy<\/div>\n
   energy_array(i)= ST_energy<\/div>\n
   *IF, ST_energy, GT, my_energy, THEN<\/div>\n
     my_energy = ST_energy   ! set the objective<\/div>\n
   *ENDIF<\/div>\n
   ETABLE,CLEAR<\/div>\n
   ALLSEL<\/div>\n
   i=i+1<\/div>\n
*ENDDO<\/div>\n
 <\/div>\n
I recived an error that harmonic analysis cannot be operated in with modal analysis. <\/div>\n
 <\/div>\n
What do you think I sholud do to reduce the amount of induced data without any deviation form the optimizer from the correct sequence ? And is there any way to use the approach I have shown ?<\/div>\n
 <\/div>\n
Regards<\/div>\n
 <\/div>\n","protected":false},"template":"","class_list":["post-287005","topic","type-topic","status-closed","hentry","topic-tag-Modal_Analysis-1","topic-tag-apdl","topic-tag-harmonic","topic-tag-optimization"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t