Learning Forum

[tristanmills]

I would like to generate Frequency Response Plots using APDL commands similar to those made in Workbench by selecting the max response for a named selection over the desired frequency range? I've looked at looping with /POST 1 commands but have run into some trouble. SET..AMP doesn't seem valid with a Cylindrical Coordinate System (RSYS not equal to SOLU).nnIs there a better way to do this? Something built into /POST26?n

[dlooman]

It is possible to plot the amplitude of the complex harmonic result in POST26 with PLCPLX,0 (the default), but results are in the solution coordinate system and can't be transformed to cylindrical in POST26. The problem with SET,,,,AMP (or HRCPLX,,,361) in POST1 is that the amplitude is computed using SRSS and the sign of the xyz component values are lost. This makes it impossible to transform the result into the cylindrical coordinate system. There's also no capability in APDL to provide Frequency Response results for a surface as is possible in Mechanical. It might not be practical, but nodes could be rotated into the cylindrical coordinate system before solution and then the solution coordinate system for those nodes would be cylindrical.n

[tristanmills]

Thank you, I came to a similar conclusion. We ended up taking the approach of getting the SET,,,,REAL & SET,,,,IMAG in /POST1 in the user CS, , looping through each frequency, then computing the Amplitudes manually (SRSS), find the max, and write out the results. I was surprised there was not a more native way to do this, since harmonic amplitudes in a Cylindrical System seem to be a pretty standard thing to want. In this case, Mechanical WB really adds some nice features. Thanks again!n