Learning Forum

[Md_Salem]

Hi evey one

I used the next code to extract the potential energy of harmonic analysis (10 steps) for some parts of structure simulated with element 185 . 

*DIM,energy_array,ARRAY,10
/POST1
i=1
*DO, step, 1,19, 2 
   SET,,,,,,,STEP       ! store results for set step
   ESEL,S,ENAME,,185
   ETABLE,ENERGY,SENE
   SSUM
   
   *GET,my_energy,SSUM,,ITEM,ENERGY
   energy_array(i)= my_energy
   
   *CFOPEN,ENERGIES,txt,C:\Users\MD\Desktop
  *VWRITE,energy_array
  %(F18.10)
  *CFCLOS
   
   ETABLE,CLEAR
   
   
   ALLSEL
   i=i+1
*ENDDO

Unfortunately the file ENERGIES.txt is created but empty !!!

Also I need to set parameter "my_energy" to record the highst value of the harmonic steps rather than recording last step as this code do.

would any one help me with that code ?

Regards

[Md_Salem]

I solved the first problem by using *MWRITE command after the DO loop and it worked properly.

Still the second problem for me : how to set parameter “my_energy” to the highest value of the steps :

*DIM,energy_array,ARRAY,10
/POST1
i=1

*DO, step, 1,19, 2
set,,,,,,,step ! store results for set step
ESEL,S,ENAME,,185
etable,energy,sene
ssum

*get,my_energy,ssum,,ITEM,energy
energy_array(i)= my_energy
ETABLE,CLEAR
ALLSEL
i=i+1
*ENDDO

*MWRITE,energy_array,C:\Users\MD\Desktop\ENERGIES,TXT
(F18.10)

Regads

[Chandra Sekaran]

1) On issue 1 I think *VWRITE should also work if you use the starting index number like below. Also I am notsure what the % sign is on the format so I removed it.

   *CFOPEN,ENERGIES,txt,C:\Users\MD\Desktop
  *VWRITE,energy_array(1)
  (F18.10)
  *CFCLOS

2) I am not sure what you mean by "the highst value of the harmonic steps rather than recording last step as this code do." Let us say you requested harmonic excitation frequency between 10 and 15 Hz and asked for 5 equally spaced steps. You will get 5 solutions at 11,12,13,14,15 Hz. Can you explain your question in this scenario?

 

[Md_Salem]

Hi Chandra,

 

I apologise for any confusion.

 

I mean that the parameter "my_energy" continues changing at each step in the displayed *DO loop. However, it retains the value of the last step of the SENE energy. I need the parameter "my_energy" to hold the maximum value over *DO loop steps.

 

In other words, assuming the values of "my_energy" at the five steps you provided are 1.1, 1.2, 1.3, 1.1, and 0.9, respectively, the final value of "my_energy" in the supplied code should be 0.9. I require the maximum value, which is "1.3" I hope that makes sense.

Regards

[Claudio Pedrazzi]

Concerning the question about getting the maximum value, if I understand correctly, the problem is that everytime you go through the loop, you overwrite my_energy.  I would simply use an additional storage variable like max_my_energy and initialise it to 0 before the loop begins, then in every step you should simply compare my_energy with the maximum until there, and if higher, substitute it.  

*IF,my_energy,GT,max_my_energy,THEN

max_my_energy=my_energy

*ENDIF

[Chandra Sekaran]

Oh I see. I did not catch on to what you meant. Yes, the above should work.

[Chandra Sekaran]

If you have the array energy_array filled then you can also use (outside the loop) "*VSCFUN,maxval,MAX,energy_array(1) " . This will return the maximum value and store it in APDL parameter maxval.