The primary analysis steps in the linear perturbation procedure are as follows:
Issue the RESCONTROL command in the nonlinear (base) electromagnetic analysis to specify at which operating point data should be saved for the multiframe restart in the first phase of the linear perturbation analysis.
If no RESCONTROL command is issued, the linear perturbation starts at the last converged substep of the nonlinear analysis.
In the first phase of the linear perturbation analysis, specify the operating point (load step, substep) and the linear perturbation analysis type, then regenerate the tangent matrices using the following commands, respectively:
In the second phase of the linear perturbation analysis, apply the linear perturbation loads and obtain the perturbed solution (SOLVE).
The results of the linear perturbation analysis are written to the Jobname.rstp file. Issue the FILE,,RSTP and SET commands to review the linear perturbation analysis results.
Permanent magnets (MP,MGXX, also MGYY, MGZZ) are supported in a linear perturbation harmonic analysis. Although they contribute only to the base (operating point solution), they should not be removed from the model in the linear perturbation analysis.
For more information, see General Procedure for Linear Perturbation Analysis in the Structural Analysis Guide.