A typical ABAQUS/Standard modal frequency response analysis uses a frequency step followed by multiple steady-state dynamic steps (for multiple load cases) for each base state. The plug-in reads the following variables from the output database generated by the analysis:
The field output from each frequency step must include the nodal displacement (U). In addition, if you are performing a coupled structural-acoustic analysis, the field output from each frequency step must include the nodal pore or acoustic pressure (POR).
After each frequency step, there must be at least one modal steady-state dynamic step (not steady-state dynamic, direct or steady-state dynamic, subspace).
In each modal steady-state dynamic step the history output must include the generalized displacements (GU) and the phase angle of the generalized displacements (GPU) for at least one mode. If you are using ABAQUS/CAE to create the analysis job, you must use the keyword editor to request history output of GPU.
You can find sample input files for a modal steady-state dynamic analysis in “Analysis of a rotating fan using substructures and cyclic symmetry,” Section 2.2.1 of the ABAQUS Example Problems Manual and “Coupled acoustic-structural analysis of a pick-up truck,” Section 8.1.6 of the ABAQUS Example Problems Manual.