2.1. Commands Used in an HBM Analysis

The main commands used to specify a Harmonic Balance Method (HBM) analysis are listed below. For a more detailed description of available options, their default settings, recommendations, and a discussion of how various options affect the analysis, see also HBM Solution Controls. For an example of usage, see Harmonic Balance Method Examples.

Preprocessor (/PREP7) or Solution (/SOLU) commands
HROPTIssue HROPT,HBM,NH to specify:

  • the harmonic balance solution method (Method = HBM)

  • number of harmonics to be included in the analysis, an integer NH within the range 1 ≤ NH ≤ 30 (defaults to 1).

HBMOPTTo specify solution options (must be issued in the solution (/SOLU) processor). Note that cyclic symmetry (HBMOPT,CYCLIC with CYCkey=1) must be activated with this command to solve for harmonic index greater than 0.
HARFRQTo define the frequency range by setting FREQB and FREQE to the beginning and end frequency (Hz). Note the following:

  • FREQB may be greater than FREQE for a decreasing frequency sweep. However, FREQB ≤ FREQE is enforced if no continuation method is used (HBMOPT,CONTSET,OFF).

  • Specifying an array of frequency values (FREQARR) is not supported.

NSUBSTTo specify the number of substeps, NSBSTP, if no continuation method is used (only applicable for HBMOPT,CONTSET,OFF).